4,988 results on '"FINITE ELEMENT MODELLING"'
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2. Three-Dimensional Finite Element Modelling of Sealed and Unsealed Roads Considering Effects of Moving Wheel Loads
- Author
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Punetha, Piyush, Nimbalkar, Sanjay, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Cui, Zhen-Dong, Series Editor, Lu, Xinzheng, Series Editor, Rujikiatkamjorn, Cholachat, editor, Xue, Jianfeng, editor, and Indraratna, Buddhima, editor
- Published
- 2025
- Full Text
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3. Performance of Bounding Surface Plasticity in the Prediction of Progressive Soil Deformation in Integral Bridge Approaches
- Author
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Hassan, M. S. K., Liyanapathirana, D. S., Fuentes, W., Leo, C. J., Hu, P., di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Cui, Zhen-Dong, Series Editor, Lu, Xinzheng, Series Editor, Rujikiatkamjorn, Cholachat, editor, Xue, Jianfeng, editor, and Indraratna, Buddhima, editor
- Published
- 2025
- Full Text
- View/download PDF
4. Non-standard adhesives for wood-based composites: powder adhesives and bicomponent fibers.
- Author
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Hýsek, Štěpán, Sahula, Lukáš, Němec, Miroslav, Żółtowska, Sonia, Kytka, Tomáš, and Wimmer, Rupert
- Subjects
- *
FINITE element method , *DIFFERENTIAL scanning calorimetry , *SHEAR strength , *WOOD , *SCANNING electron microscopy , *ADHESIVE joints - Abstract
AbstractPowder adhesives and bicomponent fibres are widely used for composite manufacturing; mainly, they are used for glueing fibres during non-woven production. However, in the woodworking industry, they are rarely used. This study aims to investigate the possibility of powder adhesive and bicomponent fibres utilisation for gluing wood. For this purpose, epoxy-polyester powder adhesive and polyester (PES) bicomponent fibres were selected, and one-component moisture-curing polyurethane adhesive was used as a reference. The selected wood species were spruce, beech, oak and wenge. The differences between powder adhesive- and bicomponent fibre-glued wood joints were observed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). Mechanical properties of glued wood joints were characterised by tensile shear strength and modelled using finite element modelling (FEM). The adhesives were further characterised using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The wood joints produced by all combinations of selected wood species and adhesives were comprehensively characterised. The highest values of tensile shear strength were reached by powder epoxy-polyester adhesive (14.85 MPa), whereas joints bonded by bicomponent fibres (5.19 MPa) reached lower values than reference samples. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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5. Efficient design of composite honeycomb sandwich panels under blast loading.
- Author
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Sawant, Rashmi and Patel, Shivdayal
- Abstract
Hybrid composite honeycomb sandwich structures (HCHSS) were employed due to high specific strength and stiffness and higher impact resistance property required for the aerospace and defence fields. The numerical modelling of the efficient HCHSS was developed for the core, front and back face plate using the C3D8R elements to determine the realistic failure behaviour for the honeycomb sandwich structure. The ConWep blast simulation loading was applied for the HCHSS. Advanced composite materials were used for the blast analysis of the HCHSS (carbon/epoxy, graphite/epoxy, woven basalt fibres/polypropylene and woven Kevlar fibres/polypropylene). The damage initiation and damage propagation based progressive damage modelling was developed and implemented in the VUMAT code for composite materials to determine the actual failure behaviour of the HCHSS. The face sheets used in this model were of a stainless-steel alloy AL-6XN. The sandwich structure was subjected to blast loads of 1, 2 and 3 kg of TNT and their performance was compared w.r.t both front and back-face deflection. The effectiveness of sandwich panels was further examined by altering the thickness of the core. Fibre-metal laminates (FML) were used in place of the steel face sheets in the panel in order to minimise its mass, and a thorough analysis of the panel's mass in relation to its peak deflection was carried out. Upon analysing the results, it was noted that the panel with the basalt fibre reinforced polymer (BFRP) core gave the best results compared to other composite materials. For a blast load of 3 kg TNT, the peak back face deflection (PBFD) of HCHSS with a BFRP core decreased by 10.64%, 7.61% and 4.75%, respectively, compared to panels with CFRP, GFRP, and KFRP cores. The peak deflection of the panel decreased as the BFRP core thickness increased. The energy absorption capacity of the panel also increased with increasing thickness. Additionally, it was found that panels with BFRP cores and KFRP-steel laminate face sheets provided the optimum balance of strong blast resistant performance and light weight. Compared to the metallic (steel) sandwich panel, the mass of the sandwich panel with KFRP-steel laminate face sheets and BFRP core was reduced by 33%, but at the same time, its PBFD increased by almost 50%. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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6. Thermal simulation of Al alloy developed by wire arc additive manufacturing using finite element analysis.
- Author
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Mishra, Ipsit and Srivastava, Rajeev
- Abstract
Wire Arc Additive Manufacturing (WAAM) is a direct energy deposition (DED) technology which utilizes electric arc as a heat source and feedstock as metal wire. It has the highest deposition rate with less material consumption. Having low melting efficiency, heat input is high which can lead to thermal distortion and residual stress. Thermal management can mitigate heat accumulation. In the present work, thermal simulation of 3-D geometry using finite element analysis has been done to predict the thermal behavior of WAAM fabricated Aluminum part by ANSYS 2021 R2 software. The wire and substrate used were Al 5183 and AA 6061 T6 respectively owing to having greater thermal properties. Temperature profile and heat flux distribution for substrate have been analyzed using Goldak heat source model. It has been found that at the end of simulation, the topmost layer of weld bead achieved temperature of about 437 °C and substrate reached about 250 ℃. The minimum and maximum heat flux were found as 0.418 W/mm
2 and 2.932 W/mm2 respectively. It has been observed that the temperature of substrate started increasing slowly near the bead deposition area but at the end of simulation, the temperature near weld bead became high. At the same time, surface temperature got reduced. Lower layer of the weld bead got a certain time to get cooled. Heat dissipation was high as Aluminum has high thermal conductivity which maintained the uniform temperature distribution throughout the bead. This simulation will help to predict the thermal behavior and analysis of components developed by WAAM process. Highlights: A 3D model of substrate and weld bead. Thermal simulation of Al part made by WAAM. Analysis of temperature-time and heat flux distribution. [ABSTRACT FROM AUTHOR]- Published
- 2024
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7. An electrical engineering perspective on naturality in computational physics.
- Author
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Kotiuga, P. Robert and Lahtinen, Valtteri
- Abstract
We look at computational physics from an electrical engineering perspective and suggest that several concepts of mathematics, not so well-established in computational physics literature, present themselves as opportunities in the field. We discuss elliptic complexes and highlight the category theoretical background and its role as a unifying language between algebraic topology, differential geometry, and modelling software design. In particular, the ubiquitous concept of naturality is central. Natural differential operators have functorial analogues on the cochains of triangulated manifolds. In order to establish this correspondence, we derive formulas involving simplices and barycentric coordinates, defining discrete vector fields and a discrete Lie derivative as a result of a discrete analogue of Cartan’s magic formula. This theorem is the main mathematical result of the paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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8. Micromechanical modelling for bending behaviour of novel bioinspired alumina-based dental composites.
- Author
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Jargalsaikhan, Urangua, Wan, Hongbo, Leung, Nathanael, Song, Xu, Hu, Jianan, Su, Bo, and Sui, Tan
- Subjects
- *
DENTAL crowns , *DENTAL materials , *ALUMINUM oxide , *DENTAL ceramics , *STRESS concentration - Abstract
The clinical failure mode of dental crown ceramics involves radial cracking at the interface, driven by the surface tension generated from the flexure of the ceramic layer on the subsurface. This results in a reduced lifespan for most all-ceramic dental crowns. Therefore, investigating optimal material combinations to reduce stress concentration in dental crown materials has become crucial for future successful clinical applications. The anisotropic complex structures of natural materials, such as nacre, could potentially create suitable strong and damage-resistant materials. Their imitation of natural structural optimisation and mechanical functionality at both the macro- and micro-levels minimises weaknesses in dental crowns. This research aims to optimise cost-effective, freeze-casted bioinspired composites for the manufacture of novel, strong, and tough ceramic-based dental crowns. To this end, multilayer alumina (Al 2 O 3) composites with four different polymer phases were tested to evaluate their bending behaviour and determine their flexural strength. A computational model was developed and validated against the experimental results. This model includes Al 2 O 3 layers that undergo gentle compression and distribute stress, while the polymer layers act as stress relievers, undergoing plastic deformation to reduce stress concentration. Based on the experimental data and numerical modelling, it was concluded that these composites exhibit variability in mechanical properties, primarily due to differences in microstructures and their flexural strength. Furthermore, the findings suggest that bioinspired Al 2 O 3 -based composites demonstrate promising deformation and strengthening behaviour, indicating potential for application in the dental field. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
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9. Modelling and analysis of train-track-subgrade-soil dynamic interaction subjected to the interfacial damage of slab induced by uneven settlement.
- Author
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Wang, Weidong, Li, Zheng, Xu, Lei, and Wei, Xiao
- Subjects
- *
FINITE element method , *FREQUENCIES of oscillating systems , *ACCELERATION (Mechanics) , *DYNAMICAL systems , *DYNAMIC models - Abstract
• A TTSS interaction model is established considering the damage of the track slab. • The damaged slab enlarges the vibration of the under-rail structure. • The settlement induces the resonance of the TTSS interaction system. • The mutual interference between settlement and track irregularity is discussed. In this paper, a dynamic model is established to investigate the dynamic behavior of train-track-subgrade-soil (TTSS) interaction. The effects of interfacial damage of the track slab induced by soil settlement on the dynamic interaction system are considered. The model framework is established by the finite element method. The soil settlement-induced track deformation is calculated by a practical iteration algorithm, where the nonlinear interfacial damage is simulated by the cohesive zone model. The simulation model is verified by comparison with other models. In regards to the excitations of the dynamic TTSS interaction system, two types of track irregularities are considered, namely the conventional track irregularities generated by known spectrums, and the additional irregularities caused by soil settlement. In the numerical study, the dynamic performances of the TTSS interaction subjected to interfacial damage, and soil settlement are compared. Next, the short wavelength irregularity is discussed as well. From the results, the vibration enhancement can be observed in the time and frequency domain. The interfacial damage of the track enhances the vibration both in low- and high-frequency domains, while the impacts of settlement are only observed in the frequency band of 0∼3 Hz. The frequency band of vibrations triggered by short wavelength irregularities is correlated with its wavelength range. Moreover, the settlement with different wavelengths and amplitudes is studied. It is shown that the increase of settlement amplitude and decrease of settlement wavelength lead to higher damage degree in amplitude and wider spatial distribution. In regards to the dynamic responses, the vehicle accelerations, wheel-rail contact forces, track displacement, and soil displacement are more sensitive to the settlement amplitudes varying from 10 to 80 mm, while the sensitive settlement wavelength is concentrated in 20 to 40 m. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. Failure pattern in ceramic metallic target under ballistic impact.
- Author
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Iqbal, M. A. and Khan, M. K.
- Subjects
ALUMINUM alloys ,FINITE element method ,ENERGY dissipation ,PROJECTILES ,CERAMICS - Abstract
The ballistic resistance and failure pattern of a bi-layer alumina 99.5% - aluminium alloy 1100-H12 target against steel 4340 ogival nosed projectile has been explored in the present experimental cum numerical study. In the experimental investigation, damage induced in the ceramic layer has been quantified in terms of number of cracks developed and failure zone dimensions. The resultant damage in the backing layer has been studied with variation in the bulge and perforation hole in the backing layer with the varying incidence velocity. The discussion of the experimental results has been further followed by three dimensional finite element computations using ABAQUS/Explicit finite code to investigate the behaviour of different types of bi-layer targets under multi-hit projectile impact. The JH-2 constitutive model has been used to reproduce the behaviour of alumina 99.5% and JC constitutive model has been used for steel 4340 and aluminium alloy 1100-H12. The total energy dissipation has been noted to be of lesser magnitude in case of sub-sequential impact in comparison to simultaneous impact of two projectiles. The distance between the impact points of two projectiles also effected the ballistic resistance of bi-layer target. The ballistic resistance of single tile ceramic front layer and four tile ceramic of equivalent area found to be dependent upon the boundary conditions provided to the target. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. An Experimental and Numerical Study on the Lateral Stiffness Limits of Straddle-Type Monorail Tour-Transit Systems.
- Author
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Zhang, Hong, Wang, Pengjiao, Li, Qin, Jin, Junhui, Wei, Shiqi, Guo, Fengqi, Feng, Cheng, and Deng, Qun
- Subjects
MULTIBODY systems ,LATERAL loads ,FINITE element method ,WIND pressure ,SENSITIVITY analysis - Abstract
The development of the straddle-type monorail tour-transit system (MTTS) has received keen attention. Regarding the unspecified regulations on the lateral stiffness limit of steel substructures, which is essential for the design of MTTSs, this work presents a comprehensive assessment of the issue. Firstly, a wind–vehicle–bridge coupling model was established, integrating multibody dynamics and finite element methods. This model was then validated against field test results, considering measured track irregularities and simulated wind loadings as the excitations. Afterwards, a trend analysis and a variance-based sensitivity analysis was performed to investigate the effect of various factors on the dynamic response of the MTTS. Results indicate that the pier height significantly impacts the lateral displacement of the pier top, accounting for 87% of the first-order sensitivity index and 75% of the total sensitivity index. In comparison, the lateral stiffness of track beams contributes over 70% to the maximum responses at the mid-span. Based on this, two responses, the lateral displacement of the pier top and the lateral deflection–span ratio of the track beam, were utilized as evaluation indicators. With the analysis of indicators in terms of lateral acceleration, Sperling index, and lateral wheel force, the limited values for the two indicators were determined as 8.04 mm and L/4200, respectively. These findings can serve as valuable references for future research and designs in this field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Simulation of blind pre-diction and post-diction shaking table tests on a masonry building aggregate using a continuum modelling approach.
- Author
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Aşıkoğlu, Abide, D'Anna, Jennifer, Ramirez, Rafael, Solarino, Fabio, Romanazzi, Antonio, Ciocci, Maria Pia, and Bianchini, Nicoletta
- Subjects
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STONEMASONRY , *SHAKING table tests , *FINITE element method , *MASONRY testing , *SEISMIC testing - Abstract
Masonry buildings of historical centres are usually organized within aggregates, whose structural performance against seismic actions is challenging to predict and constitutes still an open issue. The SERA—AIMS (Seismic Testing of Adjacent Interacting Masonry Structures) project was developed to provide additional experimental data by testing a half-scale, two-unit stone masonry aggregate subjected to two horizontal components of dynamic excitation. In this context, this paper investigates the reliability of the modelling approach and the assumptions adopted to generate a three-dimensional continuum finite element model. The work involves two stages, namely a blind pre-diction and a post-diction phase, and proposes a series of simulation analyses including a strategy to shorten the actual records and save computation costs. The study was performed to investigate the extent of uncertainty in modelling for such masonry aggregates in relation to the experimental outcomes. Pre-diction results were proven to be not accurate in terms of predicted displacements and damage patterns. The upgrades introduced for the post-diction analyses, including the calibration of the elastic modulus and the introduction of a non-linear interface between the two units, allowed to improve the outcomes, with reasonable results in terms of predicted base shear force, displacements along Y-direction and damage pattern for the non-linear stage. The overall approach showed to be appropriate for the structural analysis of existing masonry aggregates, but the accurate modelling of this type of structure remains challenging due to the high level of uncertainties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. Novel, high throughput interface fracture testing method for thermal spray coatings: The modified cantilever bend technique.
- Author
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Mishra, Ashwini K., Abbas, Saim, Srinivasan, Dheepa, Sampath, Sanjay, and Jaya, B.Nagamani
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- *
METAL spraying , *DIGITAL images , *DIGITAL image correlation , *SURFACE coatings , *CANTILEVERS , *TEST methods , *WOODEN beams , *PANTOGRAPH - Abstract
To measure the interfacial fracture toughness of ceramic/metal interfaces such as thermal spray coatings, a novel modified cantilever beam bending method is proposed. Finite element simulations are used to determine the energy release rate and phase angle for an interfacial crack in a bi-layered cantilever for varying modulus, thickness and beam aspect ratios. A high-throughput experimental procedure for the new test geometry is presented to extract a large number of measurements of interface fracture energy from the same sample, using digital image correlation. Interfacial fracture energies G C , determined using this method are compared for thermal spray coatings of Alumina and YSZ on steel substrates. G C of these coating-substrate combinations follow the same trend as measured from four-point bending or modified clamped beam bend techniques. Advantages and limitations of the technique in comparison to other methods in practice are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
14. Analysis of Mechanical Properties and Parameter Dependency of Novel, Doubly Re-Entrant Auxetic Honeycomb Structures.
- Author
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Széles, Levente, Horváth, Richárd, and Cveticanin, Lívia
- Subjects
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HONEYCOMB structures , *COMPRESSIVE force , *FINITE element method , *METAMATERIALS , *PHOTOPOLYMERIZATION - Abstract
This study proposes a new, doubly re-entrant auxetic unit-cell design that is based on the widely used auxetic honeycomb structure. Our objective was to develop a structure that preserves and enhances the advantages of the auxetic honeycomb while eliminating all negative aspects. The doubly re-entrant geometry design aims to enhance the mechanical properties, while eliminating the buckling deformation characteristic of the re-entrant deformation mechanism. The effects of the geometric modification are described and evaluated using two parameters, offset and deg. A series of experiments were conducted on a wide range of parameters based on these two parameters. Specimens were printed via the vat photopolymerization process and were subjected to a compression test. Our aim was to investigate the mechanical properties (energy absorption and compressive force) and the deformation behaviour of these specimens in relation to the relevant parameters. The novel geometry achieved the intended properties, outperforming the original auxetic honeycomb structure. Increasing the offset and deg parameters results in increasing the energy absorption capability (up to 767%) and the maximum compressive force (up to 17 times). The right parameter choice eliminates buckling and results in continuous auxetic behaviour. Finally, the parameter dependency of the deformation behaviour was predicted by analytical approximation as well. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Aging behavior of fully 3D printed microfluidic devices.
- Author
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Shvets, Petr, Shapovalov, Viktor, Azarov, Daniil, Kolesnikov, Alexey, Prokopovich, Pavel, Popov, Alexander, Chapek, Sergei, Guda, Alexander, Leshchinsky, Mark, Soldatov, Alexander, and Goikhman, Alexander
- Subjects
- *
STRESS relaxation tests , *CHECK valves , *MECHANICAL models , *FINITE element method , *CREEP (Materials) , *MICROFLUIDIC devices , *THREE-dimensional printing - Abstract
Elements of microfluidic systems created by 3D printing offer numerous advantages, such as rapid manufacturing, low cost, and the ability to create complex 3D channel topologies. Their parameters and performance can be quickly adjusted by editing the model loaded into the printer. However, the mechanical properties of polymers used for printing are often poorly documented and can significantly change over time due to aging, relaxation, or creep effects, leading to unexpected behaviour of 3D-printed devices. To address this issue, we performed a complete mechanical characterization of the samples made by 3D printing, including stress relaxation and creep tests, at different time intervals after printing. The determined properties of the material allowed us to model the mechanical and hydrodynamical performance of the 3D-printed microfluidic device, which we demonstrate using an example of a fully printed check valve specially developed for use in microfluidic systems. This approach allows easy quantitative evaluation of the optimal production cycle and lifetime of 3D-printed microfluidic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
16. 深轮辐齿坯多工位闭式模锻材料流动规律研究.
- Author
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夏琴香, 彭冲, 刘梅华, 肖刚锋, and 徐尔灵
- Subjects
DIES (Metalworking) ,FINITE element method ,RADIAL flow ,FILLER materials ,SERVICE stations - Abstract
Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
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- View/download PDF
17. Modelling In Situ Concrete Temperature Development: The Impact of Ambient Temperature and GGBS Replacement.
- Author
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Tan, Yaowen and Tang, Kangkang
- Subjects
EXOTHERMIC reactions ,HEAT of hydration ,HYDRATION kinetics ,FINITE element method ,ARRHENIUS equation - Abstract
The rise in early-age temperature concrete structures, driven by the exothermic reactions during cement hydration, significantly increases the risk of thermal cracking. To address this issue, the construction industry employs several strategies, including the partial substitution of cement with ground granulated blast furnace slag (GGBS) due to its lower heat of hydration. Accurately predicting the hydration temperature of concrete is critical for preventing thermal cracking. This task becomes more complex, with fluctuating ambient temperatures influencing hydration kinetics and heat dissipation. Previous studies often assume adiabatic or isothermal conditions, thus overlooking the impact of ambient temperature variations. This paper presents an innovative finite element modelling (FEM) approach to simulate the hydration temperature progression in in situ concrete slabs, incorporating the effects of ambient temperature fluctuations. Isothermal calorimetry curves were adjusted using the Arrhenius-based approach to express the cement hydration rate as a function of ambient temperature. The FEM outcomes, validated with semi-adiabatic calorimetry tests, demonstrate the model's capability to forecast temperature development in in situ concrete under varying ambient conditions. Additionally, the study examines the influence of partial cement replacement with GGBS on thermal behaviour, revealing that while GGBS effectively reduces thermal reactions at higher contents, its efficacy diminishes with rising ambient temperatures. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Plastic Limited Numerical Modelling on Contact Friction Effects of Steel–Concrete Connection for Composite Bridges.
- Author
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Gosztola, Dániel, Cucuzza, Raffaele, Szép, János, Domaneschi, Marco, Ghodousian, Oveys, and Movahedi Rad, Majid
- Subjects
FINITE element method ,PLASTIC analysis (Engineering) ,COMPRESSION loads ,COMPOSITE structures ,FRICTION - Abstract
This research employs plastic limit analysis to examine load combinations, contact interactions, and friction effects on steel–concrete connections. A nonlinear finite element model was developed using ABAQUS 2021, incorporating the concrete damage plasticity model and contact friction interactions. The model's validity was confirmed through laboratory experiments. Results indicate that contact elements and friction between the top flange, concrete slab, and studs significantly influence structural behavior. Unlike conventional push-out tests, real deck–slab connections exhibit different load-displacement responses due to the self-weight and additional loads, such as vehicular traffic. Under horizontal loading, extensive failures with large deformations along the studs occur, while vertically compressive loads lead to failures around the connections. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Performance Properties and Finite Element Modelling of Forest-Based Bionanomaterials/Activated Carbon Composite Film for Sustainable Future.
- Author
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Zor, Mustafa, Şen, Ferhat, Özçelik, Orhan, Yazıcı, Hikmet, and Candan, Zeki
- Subjects
CARBON composites ,THERMOGRAVIMETRY ,DYNAMIC mechanical analysis ,ACTIVATED carbon ,THERMAL conductivity - Abstract
Thanks to its highly crystalline structure and excellent thermal, optical, electrical and mechanical properties, carbon and its derivatives are considered the preferred reinforcement material in composites used in many industrial applications, especially in the forest and forest products sector, including oil, gas and aviation. Since hydroxyethyl cellulose (HEC) is a biopolymer, it has poor mechanical and thermal properties. These properties need to be strengthened with various additives. This study aims to improve the thermal and mechanical properties of hydroxyethyl cellulose by preparing hydroxyethyl cellulose/activated carbon (HEC/AC) composite materials. With this study, composites were obtained for the first time and their mechanical properties were examined using a 3D numerical modeling technique. The thermal stability of the prepared composite materials was investigated via thermal gravimetric analysis (TGA). The samples were heated from 30 °C to 750 °C with a heating rate of 10 °C/min under a nitrogen atmosphere and their masses were measured subsequently. The mechanical properties of the composites were investigated via the tensile test. The viscoelastic properties of the composite films were determined with dynamic mechanical thermal analyses (DMTA) and their morphologies were examined with scanning electron microscopy (SEM) images. According to the results, the best F3 sample (films containing 3 wt.% activated carbon) had an elastic modulus of 168.3 MPa, a thermal conductivity value of 0.068 W/mK, the maximum mass loss was at 328.20 °C and the initial storage modulus at 30 °C was 206.13 MPa. It was determined that the hydroxyethyl cellulose composite films containing 3 wt.% activated carbon revealed the optimum results in terms of both thermal conductivity and viscoelastic response and showed that the obtained composite films could be used in industrial applications where thermal conductivity was required. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. FE Simulation of Installation and Loading of Single and Group Pressure-Grouted Micropiles.
- Author
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Elsawwaf, Ahmed and El Naggar, Hany
- Subjects
STRAINS & stresses (Mechanics) ,RADIAL stresses ,GROUTING ,FINITE element method ,BITS (Drilling & boring) - Abstract
The most influential effect of installing pressure-grouted micropiles is the increase of the radial stresses in the surrounding soil, which subsequently increases the micropile load capacity. The Increased Ks Approach has been extensively utilized in the literature for simulating this effect within finite element-based software, such as PLAXIS, and has been deemed reasonably suitable. However, this paper aims to outline the principal limitations of this approach and introduce an alternative method—the Cavity Expansion Approach—that can accurately simulate the expansion of micropiles during installation. A case study involving the installation and loading of both single and group micropiles was simulated using FE modelling to assess the efficacy of the proposed method. The findings indicate that the Increased Ks Approach results in an unrealistic stress field around the micropile following installation, with the micropile retaining a straight shape with the drill bit's initial diameter. Conversely, the Cavity Expansion Approach was found to produce reasonable stress fields, characterized by uneven increases in radial and hoop stresses within a confined zone extending up to a distance of 9 D
mp from the micropile. When implemented using prescribed pressures, the Expansion Approach yields tapered micropiles featuring rough, corrugated surfaces. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
21. Controlling strain localization in thin films with nanoindenter tip sharpness
- Author
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Stanislav Zak
- Subjects
Finite element modelling ,Nanoindentation ,Strain localization ,Thin film ,Thin multilayer ,Medicine ,Science - Abstract
Abstract Thin film nanoindentation has increased interest due to its usage in various applications. It is virtually impossible to measure thin film elastic modulus without the substrate influence. Several different methods exist to obtain the true thin film’s elastic modulus with no attention given to investigate what parameters can improve insight into thin film mechanical property measurement. A key parameter is the tip radius. This work is aimed at quantifying the influence of the tip radius on the strain field under the indenter. Three Berkovich indentation tips with different tip radii were used for thin multilayer nanoindentation with numerical modelling. The results confirm the existence of the large elastically deformed zone, with a strong localization under the tip. Comparison between the experiments and numerical model shows direct connection between the tip radius and strain localization affecting the experiment, emphasizing importance of knowing the tip radius.
- Published
- 2024
- Full Text
- View/download PDF
22. Failure pattern in ceramic metallic target under ballistic impact
- Author
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M.A. Iqbal and M.K. Khan
- Subjects
Ballistic resistance ,Bi-layer target ,Ceramic metal armour ,Multi-hit impact ,Finite element modelling ,Military Science - Abstract
The ballistic resistance and failure pattern of a bi-layer alumina 99.5% - aluminium alloy 1100-H12 target against steel 4340 ogival nosed projectile has been explored in the present experimental cum numerical study. In the experimental investigation, damage induced in the ceramic layer has been quantified in terms of number of cracks developed and failure zone dimensions. The resultant damage in the backing layer has been studied with variation in the bulge and perforation hole in the backing layer with the varying incidence velocity. The discussion of the experimental results has been further followed by three dimensional finite element computations using ABAQUS/Explicit finite code to investigate the behaviour of different types of bi-layer targets under multi-hit projectile impact. The JH-2 constitutive model has been used to reproduce the behaviour of alumina 99.5% and JC constitutive model has been used for steel 4340 and aluminium alloy 1100-H12. The total energy dissipation has been noted to be of lesser magnitude in case of sub-sequential impact in comparison to simultaneous impact of two projectiles. The distance between the impact points of two projectiles also effected the ballistic resistance of bi-layer target. The ballistic resistance of single tile ceramic front layer and four tile ceramic of equivalent area found to be dependent upon the boundary conditions provided to the target.
- Published
- 2024
- Full Text
- View/download PDF
23. Mechanical influence of facet tropism in patients with chronic discogenic pain disorder
- Author
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Jun Y. Lee, Hae I. Lee, Sang-Heon Lee, and Nack H. Kim
- Subjects
discogenic pain ,facet tropism ,disc degeneration ,finite element model ,facet tropisms ,intervertebral discs ,facets ,intradiscal pressures ,discography ,intervertebral disc degeneration ,finite element modelling ,disc herniation ,mechanical stress ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
Aims: The presence of facet tropism has been correlated with an elevated susceptibility to lumbar disc pathology. Our objective was to evaluate the impact of facet tropism on chronic lumbosacral discogenic pain through the analysis of clinical data and finite element modelling (FEM). Methods: Retrospective analysis was conducted on clinical data, with a specific focus on the spinal units displaying facet tropism, utilizing FEM analysis for motion simulation. We studied 318 intervertebral levels in 156 patients who had undergone provocation discography. Significant predictors of clinical findings were identified by univariate and multivariate analyses. Loading conditions were applied in FEM simulations to mimic biomechanical effects on intervertebral discs, focusing on maximal displacement and intradiscal pressures, gauged through alterations in disc morphology and physical stress. Results: A total of 144 discs were categorized as ‘positive’ and 174 discs as ‘negative’ by the results of provocation discography. The presence of defined facet tropism (OR 3.451, 95% CI 1.944 to 6.126) and higher Adams classification (OR 2.172, 95% CI 1.523 to 3.097) were important predictive parameters for discography-‘positive’ discs. FEM simulations showcased uneven stress distribution and significant disc displacement in tropism-affected discs, where loading exacerbated stress on facets with greater angles. During varied positions, notably increased stress and displacement were observed in discs with tropism compared to those with normal facet structure. Conclusion: Our findings indicate that facet tropism can contribute to disc herniation and changes in intradiscal pressure, potentially exacerbating disc degeneration due to altered force distribution and increased mechanical stress. Cite this article: Bone Joint Res 2024;13(9):452–461.
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- 2024
- Full Text
- View/download PDF
24. Resistance to progressive collapse of monolithic frames of buildings at localized damage of nodes from push-through
- Author
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A. V. Alekseytsev and M. D. Antonov
- Subjects
mechanical safety ,push-through ,local damage ,emergency situation ,progressive failure ,deformations ,finite element modelling ,Architecture ,NA1-9428 ,Construction industry ,HD9715-9717.5 - Abstract
Introduction. When designing buildings and structures it is necessary to ensure mechanical safety throughout the life cycle of the object. During the operation of buildings, situations arise in which monolithic load-bearing structures acquire defects in the area of the slab-column connection (SCC) in girderless slabs. These are, first of all, cracks caused by bending of slabs and slab pushing through by columns. The problem of taking into account the operation of structures with regard to such data of local damages in emergency situations is not sufficiently studied. In a number of cases the loss of bearing capacity of nodes is of brittle nature, which is not allowed by normative documents, as it can lead to progressive, including avalanche-like, destruction of neighboring elements.Materials and methods. The bearing capacity of elements and the degree of resistance to progressive failure of a 9-storey monolithic girderless frame under different scenarios of initial local damages are determined. Three levels of such damage are introduced, and the slab and column connection nodes are modeled by volumetric finite elements. Verification of the computational model is performed experimentally by in-situ pushover tests of the SCC under central load application. Simulia Abaqus software package is used for the purpose of calculations. The CDP model is used for modelling of concrete deformations, and bilinear diagrams with hardening are used for modelling of reinforcement deformations.Results. Experimental data on the deformations of the slab-column connection under longitudinal force loading and realization of the push-through mode are obtained. Taking into account the selected damage levels and experimental data, calculations of the monolithic frame with different damage scenarios in the investigated nodes are carried out. The nature of force redistribution for frames with different levels of such damage and the degree of their danger in the realization of progressive failure are established.Conclusions. It is determined that damages in the nodes of column and girderless slabs interfaces can lead to redistribution of forces and changes in the character of slab operation. These changes can initiate progressive failure in emergency situations in case of structural solutions of nodes with two-sided and three-sided design contours in terms of CP 63.13330 for push-through calculations. Additional design justification is required for such nodes.
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- 2024
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25. Assessment of critical parameters affecting the behaviour of bearing reinforced concrete walls under fire exposure
- Author
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Assad, Maha, Hawileh, Rami, Karaki, Ghada, Abdalla, Jamal, and Naser, M.Z.
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- 2024
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26. Parametric study of combined piled raft foundation for uniformly distributed surcharge over raft top surface.
- Author
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Singh, Gyan Garima, Tiwari, RP, and Kumar, Vijay
- Abstract
Piled raft foundations are a popular solution for supporting heavy structures on weak soils, but their design and analysis can be complex due to interaction among the raft, piles and subsoil underneath. The present study utilises finite element method to analyse the parametric dependence of ratio of average settlement (λavg), ratio of differential settlement (λdiff), ratio of shear force (SFR), ratio of bending moment (BMR) and ratio of load-sharing (χpr), for square raft with underneath connecting circular cross section piles for uniformly distributed surcharge all over the top surface of raft. The parameters varied are spacing to diameter ratio (S/D) of 2-20, diameter of piles (D) of 0.4 m-1.6 m, length to diameter ratio (L/D) of 8, 12 and 16, pile group to width of raft ratio (Wg/Wr) of 0.15-0.9 and raft-soil stiffness (Krs) of 0.069, 0.558 and 1.88 corresponding to raft thickness (tr) of 0.5 m, 1.0 m and 1.5 m respectively. The results of the present study depicts that the minimum values of λavg and λavg are observed at S/D ratio of 5 (approx.), lower Krs and larger Wg/Wr. To enhance χpr, smaller pile spacing (S) and larger pile length (L) are needed. Minimum SFR and BMR are achieved at lower and larger L/D ratios, respectively. The findings can be used to guide the design and analysis of pile raft foundations for a variety of applications, including high-rise buildings, bridges, and industrial structures. [ABSTRACT FROM AUTHOR]
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- 2024
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27. Influence of vehicular movement on the seismic response and fragility of highway bridge structures.
- Author
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Patel, Jainish Maheshbhai and Ghosh, Jayadipta
- Subjects
- *
SEISMIC response , *HEAVY elements , *FINITE element method , *BRIDGE floors , *EARTHQUAKES , *BRIDGES , *CONTINUOUS bridges - Abstract
Recognising the criticality of highway bridges for the socio-economic development of a nation, multiple researchers have endeavoured towards quantifying the seismic fragility of these key infrastructure elements. Given the present boom in urbanisation, however, there may also be an appreciable likelihood of vehicle presence on the highway bridge deck during an earthquake event. This study focuses on the impact assessment of vehicle-bridge-interaction (VBI) on the seismic fragility of highway bridges by explicitly accounting for vehicular movement atop the bridge deck during seismic shaking. Addressing existing drawbacks in literature that typically adopts a simplified modelling strategy and static vehicle placement, this paper considers different types of moving vehicles (modelled as mass-spring-dashpot system analogies) for VBI assessment through a novel algorithm. The proposed framework also accounts for uncertainties involved in the moving vehicle analysis, pertaining to vehicle characteristics and driver's perception of the earthquake. The framework is demonstrated on representative multi-span continuous steel girder bridges located in Central and Southeastern United States. A comparative assessment of hysteretic response of bridge components and seismic fragility curves indicate a considerable influence of vehicular movement on bridge damage, signifying the importance of considering moving VBI effects for thorough seismic assessment of highway bridge structures. [ABSTRACT FROM AUTHOR]
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- 2024
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- View/download PDF
28. Distributions of Stress and Strain in Concrete Filled Steel Tube Beams.
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Le, K. B., Le, V. T., and Cao, V. V.
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STEEL tubes ,GIRDERS ,CONCRETE ,STRUCTURAL engineers ,FINITE element method - Abstract
Copyright of International Journal of Engineering Transactions C: Aspects is the property of International Journal of Engineering (IJE) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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29. Modelling In Situ Concrete Temperature Development: The Impact of Ambient Temperature and GGBS Replacement
- Author
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Yaowen Tan and Kangkang Tang
- Subjects
ground granulated blast furnace slag ,finite element modelling ,isothermal calorimetry ,arrhenius equation ,semi-adiabatic calorimetry ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The rise in early-age temperature concrete structures, driven by the exothermic reactions during cement hydration, significantly increases the risk of thermal cracking. To address this issue, the construction industry employs several strategies, including the partial substitution of cement with ground granulated blast furnace slag (GGBS) due to its lower heat of hydration. Accurately predicting the hydration temperature of concrete is critical for preventing thermal cracking. This task becomes more complex, with fluctuating ambient temperatures influencing hydration kinetics and heat dissipation. Previous studies often assume adiabatic or isothermal conditions, thus overlooking the impact of ambient temperature variations. This paper presents an innovative finite element modelling (FEM) approach to simulate the hydration temperature progression in in situ concrete slabs, incorporating the effects of ambient temperature fluctuations. Isothermal calorimetry curves were adjusted using the Arrhenius-based approach to express the cement hydration rate as a function of ambient temperature. The FEM outcomes, validated with semi-adiabatic calorimetry tests, demonstrate the model’s capability to forecast temperature development in in situ concrete under varying ambient conditions. Additionally, the study examines the influence of partial cement replacement with GGBS on thermal behaviour, revealing that while GGBS effectively reduces thermal reactions at higher contents, its efficacy diminishes with rising ambient temperatures.
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- 2024
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30. Accurate finite element modelling of knots and related fibre deviations in structural timber
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Khaled Saad and András Lengyel
- Subjects
Timber ,Knot ,Fibre paradigm ,Finite element modelling ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The primary purpose of the pursued research presented in this article was to propose a new technique to create the actual three-dimensional geometry of knots and related fibre deviations and eliminate the inconsistency between modelling the knots as openings or solids. The geometrical and mechanical characteristics of knots and related local disturbed fibre patterns were numerically modelled. The numerical models were experimentally validated by four-point bending tests performed on six timber beams made of Nordic spruce (Picea abies). Tested specimens were sliced up into several strips parallel to the grains in the vicinity of the knot to numerically generate the actual geometrical model of the knots and related fibre deviations for creating the three-dimensional fibre paradigm. The validated numerical models can also be used based on visual inspections. The user needs only to define the position and size of the knot within the timber element required for the 3D finite element model. Moreover, the model allows defining different fibre patterns in the knot vicinity. Results proved that openings can represent knots when found in the tension zone with careful adjustment of the related three-dimensional fibre deviations. Moreover, the results emphasize the need for accurate modelling for the fibre deviations rather than the knot itself.
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- 2024
- Full Text
- View/download PDF
31. Numerical investigation on the deformation of railway embankment under normal faulting
- Author
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Haohua Chen, Jiankun Liu, Zhijian Li, Xiaoqiang Liu, Jiyun Nan, and Jingyu Liu
- Subjects
Railway embankment ,Normal fault ,Finite element modelling ,Fault rupture outcropping ,Deformation pattern ,Affected zone ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract Active faults in the earthquake region are consistently regarded as a potential geological hazard to the construction and operation of railway engineering. However, the effects of normal faulting on railway embankments have not been investigated thoroughly. For bridging this knowledge gap, three-dimensional finite element analysis considering the influence of faulting offset, the soil layer’s thickness, the fault dip angle and the embankment cross-fault angle are conducted to clarify the normal faulting effects on the railway embankment. Emphasis is given to the stress and strain characteristic in the fault rupture outcropping regions on the embankment, the deformation of the embankment centerline for design purposes, and the determination of the affected zones for railway embankment preservation. The analysis shows that the normal fault rupture outcropping regions on railway embankment are tensile yield in most cases. The existence of the soil layer and its thickening would widen the affected zones and the regions where the fault ruptures outcrops. The fault dip angle and the cross-fault angle of the embankment have a complex effect on the behaviors of the crossing embankment. The depth of the subsidence zone of the embankment would increase with the decrease of the fault dip angle and the large fault dip angle would change the primary fault rupture to be a compressive one directly above the fault line. If the embankment crosses the fault line obliquely, the curvature radius of the centerline would hardly meet the design code.
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- 2024
- Full Text
- View/download PDF
32. Experimental investigation and finite element analysis of reinforced concrete beams strengthened by fibre reinforced polymer composite materials : A review
- Author
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Solahuddin Bin Azuwa and Fadzil Bin Mat Yahaya
- Subjects
Experimental ,Finite element modelling ,Fibre reinforced polymer ,Composite material ,Reinforcement ,Reinforced concrete beams ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
As a composite material, fibre reinforced polymer (FRP) has many uses. Incorporating FRP composite material enhances the reinforced concrete beams’ (RCB) performance, properties and behaviour as external reinforcement. A summary of how different FRP influences the RCB properties should be studied. This review paper discusses the use of FRP to reinforce RCB and briefly describes the topic. Previous experimental studies and finite element analysis (FEA) results showed that RCB constructed with FRP significantly improved the axial load, load-deflection, ultimate load, crack propagation, stress-strain distribution, and failure mode of RCB. Since this FRP composite material has superior strength, force, mounting and anchoring properties, it can be used as an alternate exterior reinforcement in RCB. The structural behaviour and performance of RCB can be enhanced by utilising FRP composite material in civil and structural engineering, especially in building construction projects.
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- 2024
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- View/download PDF
33. Assessing compressive mechanical behavior of woven fabric green textile composite using finite element method.
- Author
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Kumar, M., Tevatia, A., and Dixit, A.
- Subjects
- *
WEAVING patterns , *FINITE element method , *STRAIN energy , *UNIT cell , *GEOMETRIC modeling , *YARN - Abstract
The research aims to forecast the mechanical performance of a hybrid woven fabric natural composite subjected to compression, utilizing the three‐dimensional finite element method. A detailed finite element model of a plain woven fabric unit cell is created and analyzed for different materials like flax, basalt, and jute, and combinations of these materials (inter‐yarn hybrid basalt‐flax, jute‐flax and basalt‐jute fabrics). It is observed that fabric's response to compression is mainly influenced by the transverse longitudinal shear behaviour and the stiffness of the yarn cross‐section. Compression of single‐layer woven fabric involves yarn bending and compaction, resulting in varying fiber volume fractions in different areas due to compaction. The basalt‐jute hybrid plain woven fabric outperformed other plant‐based fiber fabrics with a polypropylene matrix in terms of mechanical performance under compression. Increase in yarn spacing and fabric thickness resulted in higher strain energy and displacement, attributed to changes in fiber volume fraction and crimp angle. Whereas, increasing yarn width led to a stiffer fabric due to increased contact area at the crossover region and higher bending rigidity, resulting in decreased strain energy and displacement. Importantly, this developed model can effectively simulate textile fabrics with diverse weaving patterns, material properties, and loading conditions. [ABSTRACT FROM AUTHOR]
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- 2024
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- View/download PDF
34. Experimental and numerical analysis of strength and deformation of large‐scale steel‐composite adhesive joints subjected to fatigue followed by static loading.
- Author
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Jaiswal, Pankaj R., Kumar, Rahul Iyer, Bormann, Franz, Juwet, Thibault, Luyckx, Geert, Mouton, Luc, Verhaeghe, Cedric, and De Waele, Wim
- Subjects
- *
ADHESIVE joints , *DEAD loads (Mechanics) , *DIGITAL image correlation , *NUMERICAL analysis , *FINITE element method , *DEFORMATIONS (Mechanics) - Abstract
This work reports a study of the fatigue behaviour and quasi‐static strength of full‐scale adhesively bonded steel‐composite joints. Three joints with an approximately 10‐mm‐thick layer of methyl methacrylate adhesive were manufactured in dockyard conditions. One specimen was tensile tested till failure, while two specimens were subjected to ~3.5 million fatigue cycles, followed by a residual tensile test supported with digital image correlation. The shear, longitudinal and peel strain values within the adhesive bondlines are significantly higher at the gripped sides due to the asymmetrical design of the steel brackets. All specimens showed a significantly higher shear strength than the design values defined by the shipbuilder. Fibre Bragg sensors monitored strains at steel and composite constituents and allowed to detect damage onset and evolution in tensile tested specimens. A finite element model of the joint was developed with material and interface properties based on dedicated small‐scale experiments. The simulation results of strains during a static load test corresponded closely to the DIC measurements. All specimens failed near the composite‐adhesive interface due to delamination of the composite panel. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. The Effect of Lens Shape, Zonular Insertion and Finite Element Model on Simulated Shape Change of the Eye Lens.
- Author
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Ye, Lin, Wang, Kehao, Grasa, Jorge, and Pierscionek, Barbara K.
- Abstract
The process of lens shape change in the eye to alter focussing (accommodation) is still not fully understood. Modelling approaches have been used to complement experimental findings in order to determine how constituents in the accommodative process influence the shape change of the lens. An unexplored factor in modelling is the role of the modelling software on the results of simulated shape change. Finite element models were constructed in both Abaqus and Ansys software using biological parameters from measurements of shape and refractive index of two 35-year-old lenses. The effect of zonular insertion on simulated shape change was tested on both 35-year-old lens models and with both types of software. Comparative analysis of shape change, optical power, and stress distributions showed that lens shape and zonular insertion positions affect the results of simulated shape change and that Abaqus and Ansys show differences in their respective models. The effect of the software package used needs to be taken into account when constructing finite element models and deriving conclusions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Extension of a Contact Subroutine for Composite Ring Rolling to Include Temperature Dependency.
- Author
-
Kluge, Laurenz, Stergianou, Stefan, Gouverneur, Moritz, and Bailly, David
- Subjects
YIELD stress ,FINITE element method ,COMPOSITE materials - Abstract
By combining the ring rolling and roll bonding processes, the product spectrum can be additionally expanded. Since a successful composite ring rolling process requires a higher growth tendency for the inner ring, previous publications commonly included a softer inner ring to reduce the flow resistance of the inner ring or specific geometries for rings and tools. In this work, the material combination of a 100Cr6 (DIN 1.3505, AISI 52100) outer ring and a 42CrMo4 (DIN 1.7225, AISI 4140) inner ring is used to show that the composite ring rolling process is also possible for material combinations with a balanced flow stress ratio and equal wall thicknesses. In earlier publications, the influence of temperature was neglected. As the influence on the yield stress and thus on the success of the process has a significant influence, this should be considered in order to be able to make a reliable statement. For this purpose, the bond formation of the two materials was investigated by bonding experiments, and an existing bond formation model was extended with respect to the temperature dependency. On the basis of this model, the process control parameters were investigated using FE simulations, and a ring rolling experiment was carried out. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Wear protection assessment of ultralow viscosity lubricants in high-power-density engines: A novel wear prediction algorithm.
- Author
-
Blanco-Rodríguez, Javier, Porteiro, Jacobo, López-Campos, José A., Cortada-García, Martí, and Fernández-Castejón, Silvia
- Subjects
LUBRICATING oils ,FINITE element method ,DYNAMIC loads ,ENGINES ,VISCOSITY ,ELASTOHYDRODYNAMIC lubrication ,JOURNAL bearings ,ELASTIC deformation - Abstract
Durability and reliability have been studied for decades through intensive trial-error experimentation. However, there are numerous fields of application where the costs associated with this approach are not acceptable. In lubricated machines with severe dynamic loads, such as high-power-density engines, simulation tools offer clear advantages over intensive testing. Prototypes and multiple scenarios can be cost-effectively simulated to assess different lubricants and engine configurations. The work presented here details the study of wear based on a validated elastohydrodynamic (EHD) simulation model of the connecting rod journal bearing. This model accounts for elastic deformation through a connecting rod finite element model (FEM). In addition, multiple lubricant rheological and tribological dependences, determined by specific experimental tests, are applied in the model through their interaction with the simulation software. Correspondingly, a novel wear algorithm is proposed to predict wear depth over time evolution along a proposed wear cycle based on the typical working ranges of high-performance engines. A final assessment is presented to compare 4 different ultralow-viscosity lubricants in their protective performance under severe conditions. The results show the evolution of the wear load and wear depth over the wear cycle. This evaluation is key to describing a lubricant selection procedure for high-power-density engines. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Numerical Modelling of Corrugated Paperboard Boxes.
- Author
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Aduke, Rhoda Ngira, Venter, Martin P., and Coetzee, Corné J.
- Subjects
CORRUGATED paperboard ,FINITE element method ,BEND testing ,COMPRESSION loads ,PACKAGING design - Abstract
Numerical modelling of corrugated paperboard is quite challenging due to its waved geometry and material non-linearity which is affected by the material properties of the individual paper sheets. Because of the complex geometry and material behaviour of the board, there is still scope to enhance the accuracy of current modelling techniques as well as gain a better understanding of the structural performance of corrugated paperboard packaging for improved packaging design. In this study, four-point bending tests were carried out to determine the bending stiffness of un-creased samples in the machine direction (MD) and cross direction (CD). Bending tests were also carried out on creased samples with the fluting oriented in the CD with the crease at the centre. Inverse analysis was applied using the results from the bending tests to determine the material properties that accurately predict the bending stiffness of the horizontal creases, vertical creases, and panels of a box under compression loading. The finite element model of the box was divided into three sections, the horizontal creases, vertical creases, and the box panels. Each of these sections is described using different material properties. The box edges/corners are described using the optimal material properties from bending and compression tests conducted on creased samples, while the box panels are described using the optimal material properties obtained from four-point bending tests conducted on samples without creases. A homogenised finite element (FE) model of a box was simulated using the obtained material properties and validated using experimental results. The developed FE model accurately predicted the failure load of a corrugated paperboard box under compression with a variation of 0.1% when compared to the experimental results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Experiment and performance analysis of serpentine-shaped cantilever beam for pipeline vibration-based piezoelectric energy harvester prototype development.
- Author
-
Fairuz, Wan Nabila Mohd, Nawi, Illani Mohd, Ahmad, Mohamad Radzi, and Kannan, Ramani
- Subjects
PIEZOELECTRIC transducers ,VIBRATION (Mechanics) ,STRUCTURAL failures ,CANTILEVERS ,MECHANICAL energy ,VIBRATION tests - Abstract
Pipelines produce vibrations during fluid or gas transportation. These vibrations are less likely to cause structural failure as they exist with a small magnitude and can be harvested into useful energy. This paper presents a study on the piezoelectric energy-harvesting method converting mechanical energy from pipeline vibration into electrical energy. The performance of the serpentine-shaped piezoelectric cantilever beam was observed to check whether the design can produce the highest output voltage within the allowable vibration region of the pipeline from 10 to 300 Hz through finite element analysis using COMSOL Multiphysics software (Supplementary Material). In addition, this study investigates the energy-harvesting potential of the proposed design under real pipeline vibration conditions through a lab vibration test. The harvested energy output is evaluated based on various vibration frequencies and amplitudes, which gives an idea of the device and its performance under different operating conditions. The experiment result shows that the energy harvester produced an open-circuit voltage of 10.28–15.45 V with 1 g of vibration acceleration. The results of this research will contribute to the development of efficient piezoelectric energy harvesters adapted for pipeline environments. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Using Machine Learning Algorithms to Develop a Predictive Model for Computing the Maximum Deflection of Horizontally Curved Steel I-Beams.
- Author
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Ababu, Elvis, Markou, George, and Skorpen, Sarah
- Subjects
ARTIFICIAL neural networks ,MACHINE learning ,STRUCTURAL engineering ,CURVED beams ,ENGINEERING design ,TORSIONAL load - Abstract
Horizontally curved steel I-beams exhibit a complicated mechanical response as they experience a combination of bending, shear, and torsion, which varies based on the geometry of the beam at hand. The behaviour of these beams is therefore quite difficult to predict, as they can fail due to either flexure, shear, torsion, lateral torsional buckling, or a combination of these types of failure. This therefore necessitates the usage of complicated nonlinear analyses in order to accurately model their behaviour. Currently, little guidance is provided by international design standards in consideration of the serviceability limit states of horizontally curved steel I-beams. In this research, an experimentally validated dataset was created and was used to train numerous machine learning (ML) algorithms for predicting the midspan deflection at failure as well as the failure load of numerous horizontally curved steel I-beams. According to the experimental and numerical investigation, the deep artificial neural network model was found to be the most accurate when used to predict the validation dataset, where a mean absolute error of 6.4 mm (16.20%) was observed. This accuracy far surpassed that of Castigliano's second theorem, where the mean absolute error was found to be equal to 49.84 mm (126%). The deep artificial neural network was also capable of estimating the failure load with a mean absolute error of 30.43 kN (22.42%). This predictive model, which is the first of its kind in the international literature, can be used by professional engineers for the design of curved steel I-beams since it is currently the most accurate model ever developed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Finite Element Simulation Model of Metallic Thermal Conductivity Detectors for Compact Air Pollution Monitoring Devices.
- Author
-
Mallah, Josée and Occhipinti, Luigi G.
- Subjects
- *
AIR pollution monitoring , *THERMAL conductivity , *FINITE element method , *AIR pollutants , *GAS detectors , *AIR pollution - Abstract
Air pollution has been associated with several health problems. Detecting and measuring the concentration of harmful pollutants present in complex air mixtures has been a long-standing challenge, due to the intrinsic difficulty of distinguishing among these substances from interferent species and environmental conditions, both indoor and outdoor. Despite all efforts devoted by the scientific and industrial communities to tackling this challenge, the availability of suitable device technologies able to selectively discriminate these pollutants present in the air at minute, yet dangerous, concentrations and provide a quantitative measure of their concentrations is still an unmet need. Thermal conductivity detectors (TCDs) show promising characteristics that make them ideal gas sensing tools capable of recognising different gas analytes based on their physical fingerprint characteristics at the molecular level, such as their density, thermal conductivity, dynamic viscosity, and others. In this paper, the operation of TCD gas sensors is presented and explored using a finite element simulation of Joule heating in a sensing electrode placed in a gas volume. The results obtained show that the temperature, and hence, the resistance of the individual suspended microbridge sensor device, depends on the surrounding gas and its thermal conductivity, while the sensitivity and power consumption depend on the properties of the constitutive metal. Moreover, the electrode resistance is proven to be linearly dependent on the applied voltage. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Experimental investigation and finite element analysis of reinforced concrete beams strengthened by fibre reinforced polymer composite materials : A review.
- Author
-
Bin Azuwa, Solahuddin and Bin Mat Yahaya, Fadzil
- Subjects
FIBROUS composites ,CONCRETE beams ,FINITE element method ,CONCRETE analysis ,STRUCTURAL engineering ,AXIAL loads ,COMPOSITE materials - Abstract
As a composite material, fibre reinforced polymer (FRP) has many uses. Incorporating FRP composite material enhances the reinforced concrete beams' (RCB) performance, properties and behaviour as external reinforcement. A summary of how different FRP influences the RCB properties should be studied. This review paper discusses the use of FRP to reinforce RCB and briefly describes the topic. Previous experimental studies and finite element analysis (FEA) results showed that RCB constructed with FRP significantly improved the axial load, load-deflection, ultimate load, crack propagation, stress-strain distribution, and failure mode of RCB. Since this FRP composite material has superior strength, force, mounting and anchoring properties, it can be used as an alternate exterior reinforcement in RCB. The structural behaviour and performance of RCB can be enhanced by utilising FRP composite material in civil and structural engineering, especially in building construction projects. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Numerical investigation on the deformation of railway embankment under normal faulting.
- Author
-
Chen, Haohua, Liu, Jiankun, Li, Zhijian, Liu, Xiaoqiang, Nan, Jiyun, and Liu, Jingyu
- Subjects
EMBANKMENTS ,FINITE element method ,RAILROAD design & construction ,DEFORMATIONS (Mechanics) - Abstract
Active faults in the earthquake region are consistently regarded as a potential geological hazard to the construction and operation of railway engineering. However, the effects of normal faulting on railway embankments have not been investigated thoroughly. For bridging this knowledge gap, three-dimensional finite element analysis considering the influence of faulting offset, the soil layer's thickness, the fault dip angle and the embankment cross-fault angle are conducted to clarify the normal faulting effects on the railway embankment. Emphasis is given to the stress and strain characteristic in the fault rupture outcropping regions on the embankment, the deformation of the embankment centerline for design purposes, and the determination of the affected zones for railway embankment preservation. The analysis shows that the normal fault rupture outcropping regions on railway embankment are tensile yield in most cases. The existence of the soil layer and its thickening would widen the affected zones and the regions where the fault ruptures outcrops. The fault dip angle and the cross-fault angle of the embankment have a complex effect on the behaviors of the crossing embankment. The depth of the subsidence zone of the embankment would increase with the decrease of the fault dip angle and the large fault dip angle would change the primary fault rupture to be a compressive one directly above the fault line. If the embankment crosses the fault line obliquely, the curvature radius of the centerline would hardly meet the design code. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Optimization of Failure Modes of a Ductile Connection Under Fire Conditions.
- Author
-
Liu, Yu, Huang, Shan-Shan, Burgess, Ian, and Peng, Bin
- Subjects
- *
STEEL framing , *FAILURE mode & effects analysis , *BUILDING performance , *CRITICAL currents , *IRON & steel plates - Abstract
Connections are the most vulnerable parts of a structure under fire conditions. A novel steel connection with high axial and rotational ductility has been proposed with the objective to improve the performance of steel-framed buildings in fire. Analytical model has been developed to determine the axial displacement of the top and bottom flanges of the beam end at high temperatures. A series of sub-frame models with this ductile connection have been built using Abaqus to study the influence of the characteristics of the connection part between the fin-plate part and face-plate part on the overall connection behaviour. The current critical failure mode of the ductile connection is bolt pull-out from the face-plate zone, and the tensile deformation capacity of the connection is not fully utilized. Therefore, measures to improve the bolt pull-out failure mode of the connection have been tested using the Abaqus sub-frame models, including adding a strengthening plate to the face-plate part of the connection and increasing the connection plate thickness. The simulation results show that the bearing failure of the beam web will become another critical failure mode of the connection, once the bolt pull-out failure is eliminated. To further optimize the high-temperature performance of the connection, the Abaqus steel frame models have also been used to test some measures to delay the occurrence of the beam web bearing failure, including adding strengthening plates to the part of the beam web in contact with the connection, and improving the material properties of the part of the beam web around the bolt holes at high temperatures. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. The Structural Behaviour of Cross-Laminated Timber Rib Panels in Fire.
- Author
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Kleinhenz, Miriam, Just, Alar, and Frangi, Andrea
- Subjects
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TIMBER , *FINITE element method , *FIRE testing - Abstract
In the frame of a research project, the structural behaviour in fire of cross-laminated timber rib panels were studied based on numerical investigations. The floor system consists of cross-laminated timber plates rigidly bonded to glued-laminated timber ribs. The numerical investigations comprised uncoupled thermo-mechanical simulations of two types of finite element models, a beam system and a flexible-in-shear multi-layered part, to investigate the influence of the effective width in fire. All models were validated against the experimental results of previously tested full-scale fire resistance tests. A parametric study analysed the composite cross‐sections' effective width in fire for a parameter range expected in practice and gave proposals depending on the thickness of the CLT layers. For the conservative case of thin CLT layers, a limit value of 60% of the effective width at normal temperature is proposed as effective width in fire. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Phase transformation effect on residual stress development in fusion welding of dissimilar stainless steels with different thickness.
- Author
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Dwibedi, Swagat, Kumar, Bikash, and Bag, Swarup
- Subjects
- *
STAINLESS steel welding , *PLASMA arc welding , *FUSION welding , *RESIDUAL stresses , *SOLID-state phase transformations , *DISSIMILAR welding - Abstract
The residual stress creates deleterious effects on joint properties of dissimilar welding due to differential thermophysical properties and mechanical constraints of dissimilar thickness. Accounting of solid-state phase transformation (SSPT) through the understanding of solidification behavior enhances the prediction accuracy of residual stress. The characterization of microstructural features improves the fundamental understanding of the residual stress evaluation. An attempt is made to comprehend the dependence of heat input on phase transformation and its effect on the generation of compressive residual stress in dissimilar welding. Three distinct heat inputs of 52, 63, and 77 J/mm are considered in micro-plasma arc welding (µ-PAW) of SS316L and SS310 with thicknesses of 800 µm and 600 µm, respectively. The measurement of residual stress is performed using the X-ray diffraction (XRD) method. The variation of δferrite from 11.2 to 7.9% is analogous to the variation of average δferrite lath size from 412 to 1040 nm, where inter-dendritic spacing varies from ~ 10 µm to ~ 20 µm. The solidification mode is identified as ferritic-austenitic (FA), which results in the formation of skeletal and lathy δferrite structures. Electron Backscatter Diffraction (EBSD) results show an increase in heat input leads to an increase in low-angle grain boundaries that results in a rise in the residual stress value. The phase fraction and residual stresses are computed employing a finite element (FE) based thermal-metallurgical-mechanical (TMM) model including the effect of SSPT. The reasonable agreement between the computed and experimental measurements with a maximum error of ~ 8.5% in weld size, ~ 7.5% in peak temperature, ~ 16% in retained δferrite, ~ 17% in residual stress, and ~ 5% in distortion demonstrates the reliability of the developed model. A lower level of heat input (52 J/mm) allows the formation of a high amount of δferrite, which generates comparatively more compressive stress as a disparity in thermal expansion coefficient α Ni ∼ 1.6 α Cr aids in the reduction of residual stress. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Modelling and simulation for the investigation on the ultrasonic propagation mechanism in advanced microelectronic packages.
- Author
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Yuan Chen, Dengxue Liu, Yuhui Fan, Zhongyang Wang, Xiang Wan, and Ming Dong
- Subjects
- *
MICROELECTRONIC packaging , *ULTRASONIC propagation , *ACOUSTIC field , *SOUND waves , *WAVE analysis , *ULTRASONIC transducers , *ULTRASONIC waves , *ULTRASONIC testing - Abstract
The miniaturisation, ultra-thinness and high-density multi-layer structure of advanced microelectronic packages complicate the propagation mechanism of ultrasonic waves. In this paper, a finite element model is used to simulate ultrasonic wave propagation in flip chip packages, investigating the laws of transmission and reflection at the lamination boundaries. The acoustic field of ultrasonic transducers is simulated using MATLAB and Abaqus software. The angular spectrum method (ASM) based on the Fourier transform is adopted to more precisely reveal the distribution characteristics and attenuation relationship of near-field ultrasonic waves. The influence of the frequency and size of the ultrasonic transducer on the propagation characteristics of ultrasonic waves is analysed. Based on an acoustic field map generated by the detection model, the waveform conversions of acoustic waves in a multi-layer structure are analysed. The results show that ultrasonic waves are mainly presented in the form of reflected and transmitted waves at the layered interface and the model with a perfectly matched layer (PML) has higher accuracy. Therefore, this method is applied to ultrasonic testing in a flip chip package, which cannot only effectively exclude interference from boundary reflection but also greatly improve the reliability of waveform conversions analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Accurate finite element modelling of knots and related fibre deviations in structural timber.
- Author
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Saad, Khaled and Lengyel, András
- Subjects
FINITE element method ,WOODEN beams ,GEOMETRIC modeling ,INSPECTION & review ,SILVER fir - Abstract
The primary purpose of the pursued research presented in this article was to propose a new technique to create the actual three-dimensional geometry of knots and related fibre deviations and eliminate the inconsistency between modelling the knots as openings or solids. The geometrical and mechanical characteristics of knots and related local disturbed fibre patterns were numerically modelled. The numerical models were experimentally validated by four-point bending tests performed on six timber beams made of Nordic spruce (Picea abies). Tested specimens were sliced up into several strips parallel to the grains in the vicinity of the knot to numerically generate the actual geometrical model of the knots and related fibre deviations for creating the three-dimensional fibre paradigm. The validated numerical models can also be used based on visual inspections. The user needs only to define the position and size of the knot within the timber element required for the 3D finite element model. Moreover, the model allows defining different fibre patterns in the knot vicinity. Results proved that openings can represent knots when found in the tension zone with careful adjustment of the related three-dimensional fibre deviations. Moreover, the results emphasize the need for accurate modelling for the fibre deviations rather than the knot itself. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Frictional behaviour of coated carbide tools and AISI 316L when using translational and rotatory relative movement considering dry and lubricated conditions.
- Author
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Volke, Pascal, Courbon, Cédric, Krumme, Erik, Saelzer, Jannis, Rech, Joel, and Biermann, Dirk
- Subjects
CARBIDE cutting tools ,FRICTION - Abstract
In machining, tool temperatures and thus tool wear are significantly influenced by frictional behaviour. Friction tests are used to determine the friction coefficient depending on relative speed, which serves as basis for parameterising friction models as input data for chip formation simulations. Therefore, this paper represents investigations towards the frictional behaviour of uncoated and coated (TiN, TiAlN) carbide tools when using two different relative movements (translational and rotary) and cooling lubricant conditions. In dry conditions, the investigations show insignificant influence of different engagement surfaces and testing kinematics on resulting friction. In lubricated conditions, three different friction coefficient sections were observed. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Numerical modelling of the BTA deep hole drilling process.
- Author
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Biermann, Dirk, Schmidt, Robert, Strodick, Simon, Walther, Frank, and Zabel, Andreas
- Abstract
The BTA deep hole drilling process is applied in order to produce bores with a large length to diameter ration at comparably high diameters of the bores. During drilling, first, the bore is cut by the cutting edge and shortly after that, a guide pad slides over the newly produced bore wall, burnishing the surface. These two effects condition the bore wall and alter its surface integrity depending on the process parameters. In the past, extensive destructive and non-destructive tests were conducted to obtain information on the surface integrity of the machined parts. Furthermore, a large number of in- and off-process measurements were carried out in material and cost-intensive experiments to determine values such as residual stresses or white etching layers. The presented work shows different finite element models of the BTA deep hole drilling process using continuous remeshing and, in order to reduce the calculation times, the Coupled Eulerian-Lagrangian (CEL) method as well. The results simulated based on this models comprise temperatures, process forces and surface properties that are compared to measured values from pervious works for validation. The various approaches are evaluated to determine whether they predict the bore hole surface integrity and thus support future investigations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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