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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/mm2 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]

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]

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]

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]

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 Dmp from the micropile. When implemented using prescribed pressures, the Expansion Approach yields tapered micropiles featuring rough, corrugated surfaces. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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]

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]

This study investigates the behaviour of high-performance alkali-activated slag concrete-filled double steel tubular (HACFDST) columns under axial compression. Utilizing high-performance alkali-activated slag concrete (HPAASC) in concrete-filled double steel tubes (CFDST) results in an innovative composite member combining the benefits of both technological domains. HPAASC, a sustainable substitute for conventional concrete, contributes to improved environmental friendliness, while CFDST enhances structural capabilities. Fourteen HACFDST specimens, comprising six circular and eight square sections, were tested to enhance our understanding of the structural performance of HACFDST members through experimental and numerical methodologies. A numerical model was proposed to predict the behaviour of circular and square HACFDST columns under axial compression. The assessment of experimental and numerical findings demonstrates that the proposed numerical model accurately forecasts the behavior of axially loaded HACFDST columns with circular and square sections. Increasing the L/Do or L/B ratio of the specimen results in decreased axial stiffness but enhances ductility. Additionally, beyond peak strength, square HACFDST columns exhibit a sharper decline in strength compared to their circular counterparts. As the L/Do or L/B ratio of HACFDST specimens increases from 2.88 to 7.95, the compressive strength index decreases from 1.28 to 1.2, emphasizing the need to optimize specimen dimensions to maximize the benefits of steel tube confinement. [ABSTRACT FROM AUTHOR]

The use of mechanoregulatory schemes based on finite element (FE) analysis for the evaluation of bone ingrowth around porous surfaces is a viable approach but requires significant computational time and effort. The aim of this study is to develop a combined macro–micro FE and artificial neural network (ANN) framework for rapid and accurate prediction of the site-specific bone ingrowth around the porous beaded-coated tibial implant for total ankle replacement (TAR). A macroscale FE model of the implanted tibia was developed based on CT data. Subsequently, a microscale FE model of the implant-bone interface was created for performing bone ingrowth simulations using mechanoregulatory algorithms. An ANN was trained for rapid and accurate prediction of bone ingrowth. The results predicted by ANN are well comparable to FE-predicted results. Predicted site-specific bone ingrowth using ANN around the implant ranges from 43.04 to 98.24%, with a mean bone ingrowth of around 74.24%. Results suggested that the central region exhibited the highest bone ingrowth, which is also well corroborated with the recent explanted study on BOX®. The proposed methodology has the potential to simulate bone ingrowth rapidly and effectively at any given site over any implant surface. [ABSTRACT FROM AUTHOR]

Introduction: In dermatology, inflammatory skin conditions impose a substantial burden worldwide, with existing therapies showing limited efficacy and side effects. This report aims to compare a novel immunological activation induced by hyperthermic 20 MHz high intensity focused ultrasound (HIFU) with conventional cryotherapy. The bioeffects from the two methods are initially investigated by numerical models, and subsequently compared to clinical observations after treatment of a patient with the inflammatory disease granuloma annulare (GA). Methods: Clinical responses to moderate energy HIFU and cryotherapy were analysed using numerical models. HIFU-induced pressure and heat transfer were calculated, and a three-layer finite element model simulated temperature distribution and necrotic volume in the skin. Model output was compared to 22 lesions treated with HIFU and 10 with cryotherapy in a patient with GA. Results: Cryotherapy produced a necrotic volume of 138.5 mm3 at − 92.7 °C. HIFU at 0.3–0.6 J/exposure and focal depths of 0.8 or 1.3 mm generated necrotic volumes up to only 15.99 mm3 at temperatures of 68.3–81.2 °C. HIFU achieved full or partial resolution in all treated areas, confirming its hyperthermic immunological activation effect, while cryotherapy also resolved lesions but led to scarring and dyspigmentation. Conclusion: Hyperthermic immunological activation of 20 MHz HIFU shows promise for treating inflammatory skin conditions as exemplified by GA. Numerical models demonstrate minimal skin necrosis compared to cryotherapy. Suggested optimal HIFU parameters are 1.3 mm focal depth, 0.4–0.5 J/exposure, 1 mm spacing, and 1 mm margin. Further studies on GA and other inflammatory diseases are recommended. [ABSTRACT FROM AUTHOR]

The purpose of this work is to study the effect of anisotropic plasticity on the micro-deep drawing of the 304 stainless steel foils through a combination of experimental testing and numerical modeling. A phenomenological anisotropic model, with the Yld2004-18p yield function, is used to model the anisotropic plasticity deformation of the material. Based on the miniature tensile experimental data and Voce's hardening law, the coefficients in the Yld2004-18p function were calibrated. The FE modelling was implemented using ABAQUS to simulate the micro-deep drawing experiments. The wall thickness and height of the cylindrical cup obtained by the simulation have shown to be reasonably close to the experimental values, and the distribution of ears is the same as the experimental results. It has shown that the Yld2004-18p anisotropic yield function can accurately describe the anisotropic behavior of 304 stainless steel foils during the micro-deep drawing process. [ABSTRACT FROM AUTHOR]

In this study, a detailed finite element investigation was conducted to evaluate the performance of glass fibre-reinforced polymer (GFRP) RC precast cap beam to column connections connected with epoxy-anchored reinforcement (epoxy duct connection). The developed model was initially validated against three experimental results with different anchored GFRP reinforcement considering the effect of reinforcement slippage. Different interaction models for slippage simulation were evaluated and discussed. The validated model was then utilized to investigate the effect of anchored length, bar diameters, anchored reinforcement amount, and the geometry of the connection. The results indicate that an optimum anchored length, equal to 25 times the bar's diameter, should be provided. It was also found that the precast beam-to-column element connection should be designed for a moment capacity at least 25% higher than that of the column section. Moreover, a minimum beam width, depth and beam overhanging length of 1.75, 1.6 and 0.25 times the column width respectively were recommended to be considered in design. The results from this study can provide direct guidelines for the design of precast GFRP-RC cap beam to the column connection with epoxy anchored reinforcement, especially in applications where precast elements need to be erected quickly, a novel method that can accelerate the construction of jetties and bridges. [ABSTRACT FROM AUTHOR]

This paper reports results of laboratory and 3D numerical modeled pull-out tests with steel ladders and polymeric strip reinforcements. These types of reinforcement are commonly used in reinforced soil walls constructed with concrete facing elements. Laboratory pull-out tests are required to determine accurate and realistic pull-out strength values considering the interaction of specific reinforcement and backfill materials under different confining pressures (i.e., trying to simulate the different reinforcement layer arrangements and load conditions in actual reinforced soil walls). International design Codes for reinforced soil walls provide default values for pull-out strength. However, in many cases, default values are too conservative and/or are not strictly specified for particular reinforcement types. Pull-out tests can be difficult and expensive to perform, thus not being common nor worth for the vast majority of reinforced soil wall projects. Consequently, calibrated numerical models can be useful to predict pull-out response under site-specific conditions, and provide further understanding of the mechanisms involved in the soil-reinforcement interaction. Details of the numerical approach, including relevant aspects of the soil-reinforcement interfaces, are described. Examples of calibrated numerical predictions for pull-out loads, displacements, and soil-dilatancy effects are presented. The influence of reinforcement, soil and interface stiffnesses is shown. Numerical results provide useful insight for future modelling works of the complex interaction between type-specific backfill materials and reinforcement element, relevant for investigation and/or practical design of reinforced soil walls. [ABSTRACT FROM AUTHOR]

In this study, an investigation was conducted to assess the performance of artificial intelligence (AI) and machine learning (ML) methods with distinct characteristics in various problem scenarios. Reinforcement tensile forces play a significant role in the design and performance of retaining walls (RWs). These are crucial for the stability and structural integrity of the retaining walls, preventing wall failure. For this, an attempt was made to predict the reinforcement tensile forces of the back-to-back mechanically stabilized earth (MSE) walls under train loading, which are necessary for upkeeping the transportation infrastructure. Six innovative models were created to counter this challenge that combines AI and ML techniques, i.e., LR, SVM, ANN, ANFIS, ANN-GA, and ANFIS-GA. Consequently, the genetic algorithm (GA) technique was also used to integrate new models, such as GA-ANN and GA-ANFIS. The input data for the models were derived from the parametric study conducted in the finite element analyses. Statistical measures, including root-mean-square-error (RMSE), mean-absolute-error (MAE), and coefficient-of-determination (R2), were analyzed and compared across multiple baseline methods to verify the accuracy of the suggested model. Results show that the proposed model's (ANFIS-GA) accuracy (R2) is 0.9876 and errors (RMSE and MAE) are 0.0191 and 0.0122, respectively. This model outperforms the baseline models in all relevant respects and shall precisely predict the tensile forces of the back-to-back MSE walls. [ABSTRACT FROM AUTHOR]

Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks, provide safe and smooth rides, and reduce the maintenance frequency. In this paper, the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in Abaqus. It is then compared to the performance of a ballasted track. First, slab and ballasted track models are developed to replicate the full-scale testing of track sections. Once the models are calibrated with the experimental results, the novel slab model is developed and compared against the calibrated slab track results. The slab and ballasted track models are then extended to create linear dynamic models, considering the track geodynamics, and simulating train passages at various speeds, for which the Ledsgård documented case was used to validate the models. Trains travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil, considering the issues associated with critical speeds. Various train loading methods are discussed, and the most practical approach is retained and described. Moreover, correlations are made between the geotechnical parameters of modern high-speed rail and conventional standards. It is found that considering the same ground condition, the slab track deflections are considerably smaller than those of the ballasted track at high speeds, while they show similar behaviour at low speeds. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this paper is to identify the unbalance of a specific rotor system like the double U-Joint driveshaft mounted on isotropic bearings and moving foundations. The challenge is to estimate the unbalance parameters of such system from its complex signal by considering parallel misalignment and foundation decreased stiffness as uncertainties. Methods: The equations of motion of the system were governed by finite element model (FEM) that allows related degrees of freedom and supports misaligned configurations and unbalanced loads. The uncertainty quantification was achieved by the Chebyshev inclusion (CI) method. The uncertain response generated a dataset of processed signals to train the chosen proper orthogonal decomposition and radial basis functions (POD-RBF), an estimation tool for low-dimension data. Results: The model's accuracy has been validated by numerical and experimental tests. In general, the procedure has given good accuracy when using the real data of the system. Otherwise, applying a regression for experimental systems with a mathematical-training data has drastically increased the errors by the fact of many uncertain conditions. Conclusion: The estimation results proved that the prediction accuracy is sensitive to the training data. Indeed, although using uncertainty quantification, the estimation of occurred unbalances in simulations and experiments was inaccurate compared to the one using the real-captured reduced data. Finally, the use of the proposed method has slightly improved the accuracy of both analyses. [ABSTRACT FROM AUTHOR]

The demand for small-batch manufacturing processes has increased considerably in recent years due to the need for personalized and customized products. Single point incremental forming (SPIF) has emerged as a time-efficient approach that offers increased material formability when compared to conventional sheet metal forming techniques. However, the complexity of SPIF requires a complete understanding of the material deformation mechanism. In this study, a non-conventional contactless tool in the form of hot compressed air is employed to form a polycarbonate sheet. The influence of the contactless tool on the shaping process is modeled and analyzed with a finite element modelling (FEM). Two different models were developed and coupled to estimate the resulting shape of the sheet. A CFD model was created to obtain pressure and temperature values of the air impacting the sheet, while a transient structural model was employed to study the deformation of the sheet. The research provides a working model that is able to predict the performance of this contactless incremental forming process of polymers with high accuracy. The comprehensive FE model developed in this work is able to forecast the final part geometries and dimensions in addition to the normal strain progression. It also revealed that the primary modes of deformation in SPIF were stretching, thinning, and bending. The model was validated by experimental results, and the predicted sheet deformation was compared to the one generated experimentally, and the results obtained were in good agreement. [ABSTRACT FROM AUTHOR]

This research work aims to perform a structural optimisation of a steel tower used to support a 2 MW wind turbine, considering the natural frequencies, stresses, buckling resistance, and displacement constraints, to reduce the volume of steel required for the structure. The investigated structure is modelled based on the use of a three-dimensional finite element model that includes the soil–structure interaction effect, the rotor loads and the wind nondeterministic effect acting on the steel tower. Due to the nature of the mathematical formulation presented for the dynamic effect of the wind, a statistical analysis of the dynamic response of the structure as well as the results of the nondeterministic optimisation is performed to obtain the results within a 95% confidence level. Based on the obtained results, it was shown that the optimisation process considering the dynamic nondeterministic effect of the wind leads to a project, the volume of which is 31.5% lower than the original volume and only 4.5% higher than the project obtained considering its static effect. However, it was concluded that taking to account the wind nondeterministic mathematical formulation, the optimised steel tower structural design presents greater robustness to uncertainties associated with the numerical modelling of the wind loadings. [ABSTRACT FROM AUTHOR]

The need for materials for high-temperature applications has always been a topic of research for various engineering applications. The need for materials for high-temperature applications is an important need specifically for defense and space applications where they are subjected to very high temperatures during reentry into the earth's atmosphere. Carbon/Carbon composites are promising materials for various fields of engineering. These materials are increasingly opted for due to their ability to withstand high temperatures above 3000 °C. Engineering designers have an important role in designing the components and sub-systems using these materials for high-temperature applications. Prediction of elastic constants for these materials is a significant step in the design of the components. The current work is aimed at the prediction of elastic constants. Elastic constants of unidirectional carbon/carbon composites are predicted in this work. Unit cell models of unidirectional carbon/carbon composites containing random positioning of fibers were created. Elastic constants were evaluated by applying periodic boundary conditions. The carbon/carbon test samples were fabricated to validate the predicted elastic constants. The PAN-based carbon fiber with carbon matrix was used for the fabrication of unidirectional carbon/carbon test samples. The uncertainty of measurement for the experiments was estimated using guide to the expression of uncertainty of measurement. The predicted values of elastic constants agree closely with the experimental results. [ABSTRACT FROM AUTHOR]

In the framework of the international benchmark "Vulcain tests on 3 Walls", three full scale ISO fire tests on a reinforced concrete wall, simultaneously subjected to a constant uniaxial compressive load, were conducted in CSTB in Paris, France. The duration of these tests exceeded 120 min. In order to assess the capability of available finite elements (FE) models to represent reinforced concrete structural behaviour under fire exposure, IRSN, within the scope of the Vulcain benchmark, set up a modelling with help of Mazars isotropic continuum damage mechanical model (Mazars Application de la mécanique de l'endommagement au comportement non linéaire et à la rupture du béton de structure. PhD Thesis, Univ. Paris 6, ENS Cachan, France, 1984) ran with the CAST3M software (Verpeaux et al. in Fouet, Ladevèze and Ohayon (eds), Calcul des Structures et Intelligence Artificielle, Pluralis, 1988), while a user-defined procedure was used to calculate the concrete properties taking into account load induced thermal strains (LITS). The effect of LITS according to the model of Anderberg and Thelandersson (Stress and deformation characteristics of concrete at high temperatures: 2 experimental investigation and material behavior model, Bulletin 54, Lund Institute of Technology, Lund, 1976) was considered by an explicit term in the strain decomposition. Also, the numerical simulation of three full scale ISO fire tests of Vulcain was carried out with the help of a FE model that takes into account the values of the concrete thermomechanical parameters identified. The numerical model is composed of two different parts, one for heat transfer analysis and the other one for structural analysis based on a three-dimensional FE model including concrete and reinforcing steel meshes. It is illustrated through this numerical investigation that the proposed model can predict the thermomechanical behaviour of reinforced concrete walls under fire exposure. [ABSTRACT FROM AUTHOR]

Concrete-filled steel tubes have become popular due to their desirable properties, including compressive strength, plasticity, and ease of construction. This study aimed to comprehensively analyze the axial response of short columns made of concrete-filled austenitic stainless steel tubes. The different parameters of these columns were carefully evaluated and compared to principal international design codes. This analysis gained a deeper understanding of the structural behavior of concrete-filled stainless-steel tubes under axial compression. Based on the data obtained from the parametric study, two supervised machine learning models were used to model the compression behavior of these elements, the artificial neural networks model and the random forest model. It was observed that the results obtained through machine learning algorithms provide a significantly more accurate response than the models available in design codes. Additionally, it was observed through the study that the best results were achieved with the artificial neural networks model, with a correlation coefficient of 0.99. The trained machine learning models were implemented into software, allowing the prediction of the behavior of these structures in the range of the data presented in the study. [ABSTRACT FROM AUTHOR]

Lateral wander of autonomous truck can be further improved by optimizing the uniform wander. Increase in available lane width for the autonomous trucks can increase the performance efficiency of this mode. This research is based on finding the optimum, combination of lane width increment and asphalt layer thickness reduction among different scenarios. Therefore, In this research with assumed maximum lane width of 4.35 m, difference combination of lane width and asphalt layer thickness scenarios have been analyzed using finite element modelling in ABAQUS. Considering the base pavement width of 3.75 m, increment for each scenario is 15 cm and reduction in asphalt layer thickness is at 2 cm. Performance efficiency of each scenario is conducted while considering the initial construction costs and damage assessment for each scenario. Moreover, life cycle cost analysis (LCCA) is conducted for the base scenario and selected optimum scenario. Results show that increase in pavement width beyond 4.2 m, renders the scenarios uneconomical and thus, the scenario consisting of 4.2 m lane width and 16 cm asphalt layer thickness yield a maximum performance efficiency of 20% among all other alternatives. LCCA analysis shows that a difference in salvage value of 42 million Euros exists when compared with the base scenario. By selecting the optimum lane width of 4.2 m and asphalt layer thickness of 16 cm, Pavement lifetime can be further increased by 13 years with full depth reclamation used as maintenance intervention.Article Highlights: A novel approach for increasing pavement performance efficiency by controlling initial construction costs is introduced. The impact of decreasing asphalt layer thickness and increase in lane width on pavement construction costs and its performance is described. Uniform wander mode for autonomous trucks by utilizing an increased lane width is improved. [ABSTRACT FROM AUTHOR]

Purpose: Locally resonant metamaterials are engineered structures, typically comprising a host structure with resonant structures added or included on a sub wavelength scale. Their interaction leads to stopbands, which are frequency ranges in which no free wave propagation is allowed, enabling strong vibration reduction. At present, metamaterials are mostly realized in an ad hoc manner, as mostly academic demonstrators are considered and the currently used manufacturing approaches are not yet suited for mass production. Moreover, manufacturing induced changes in metamaterial geometry and material properties are hard to account for in the early design process, which can result in off-design metamaterial performance. In this work, injection moulding is proposed as a mass-manufacturing method for resonators, and dedicated injection moulding process simulations are incorporated in the metamaterial performance predictions to account for the influence of manufacturing induced changes. Methods: The benefits of incorporating manufacturing simulations in metamaterial performance predictions are investigated for three injection moulded resonator types. Three dedicated mould inserts were manufactured, each possessing a resonator product cavity, and several sets of resonators are produced in two different materials. The masses and main dimensions of the produced resonators are measured, and their eigenfrequencies are determined using laser vibrometry. To predict the as-produced resonator shape and density distribution, injection moulding simulations are performed using the commercial software Moldex3D 2022. The resulting model meshes are next translated to structural dynamic finite element models to determine the eigenfrequencies and stopbands. Results and Conclusion: Incorporating injection moulding simulations in structural dynamic modelling clearly improves the eigenfrequency predictions of the manufactured resonators as well as the metamaterial stopband predictions. [ABSTRACT FROM AUTHOR]

For the corrugated web steel beam, the web-to-flange welded detail by geometric discontinuity plays a vital role of the stress concentration-related fatigue fracture and failure mechanism. A study of the influences of the geometries of the crack-arrest hole on the stress intensity factor and related fracture behavior is presented in this research. The source of local stress concentration is investigated through finite element modeling and compared against experimentally measured strain results first to confirm the accuracy of analysis. Additional flank-holes symmetrically distributed on both sides of the crack tip are also considered for further reducing the crack driving force. The study shows that the introduction of the additional flank-hole is beneficial for further reduction of the stress concentration near the crack tip. Moreover, the inside of the crack-arrest hole is more efficient than the outside ones in reducing the stress intensity factor, while the use of bigger hole is recommended for the halting of short crack with the crack tip away from the edge of the flange. The further arrangement of the additional flank-hole within the crack seam range is beneficial in better reduction of the stress intensity factor for the models with the crack-arrest holes only. The shorter the distance of the additional flank-hole from the crack tip is, and the larger its radius is, the greater crack halting effect becomes. [ABSTRACT FROM AUTHOR]

This study analyses the interior-two-flange (ITF) web crippling strength of roll-formed aluminum alloy lipped channels (RA channels) with web holes employing experimental testing, numerical modeling, and deep neural network (i.e., Deep belief Network, DBN). A total of 30 experimental tests on web crippling behavior were carried out, with the results utilized to validate a finite element (FE) model, developed in this study. The experimental results were compared to the data produced by the validated FE model, which was then used to train the DBN model. The results of the DBN prediction were shown to be around 5% more conservative than the FE results. In order to evaluate the effects of associated factors on the ITF web crippling strength of RA channels, a comprehensive parametric study was conducted using the DBN. The design guidelines that are currently available in the American Iron and Steel Institute (AISI 2016), the Australian and New Zealand Standards (AS/NZS 1997; AS/NZS (2018)), and the Eurocode (CEN 2007) were found to be unreliable while determining the ITF web crippling strength of RA channels. The DBN's predictions developed new formulae for calculating the web crippling strength reduction factors. After conducting a reliability study, it was found that the developed strength reduction factor equations are reliable when calculating the ITF web crippling strength of such perforated roll-formed aluminium alloy channels. [ABSTRACT FROM AUTHOR]

This study focuses on the electromechanical study of functionally graded graphene reinforced piezoelectric composite (FG-GRPC) structures using the modified Halpin Tsai (MHT) micromechanics model. Two piezoelectric material matrices, namely PZT-5H and PVDF, are reinforced with GPLs, an ultralightweight and highly rigid carbonaceous nanofiller. The developed graphene reinforced piezoelectric composites (GRPC) vary in the thickness direction to form FG-GRPC, with GPLs evenly scattered throughout the material matrix. The MHT model and Rule of the mixture (ROM) are used to determine the effective modulus of elasticity, poisson's ratio, density, and piezoelectric characteristics of the GRPC structure. The spatial variation in composition across the thickness of FG-GRPC structural tiles is determined by a simple power law distribution. The voltage and power metrics of a circuit are calculated using first order shear deformation theory and Hamilton's approach from the governing differential equations of motion. An exhaustive parametric study is undertaken with an emphasis on the effects of GPL weight percentage, material grading exponent, thickness ratio, and frequency on the circuit metrics of FG-GRPC structures. Our findings indicate that the material grading exponent and a limited number of GPLs considerably improve the circuit parameters of FG-GRPC tiles. This study will demonstrate the required physical insights for coupled modelling of microelectromechanical systems, with applications spanning pressure sensors, small ultrasonic motors, active controllers, and intelligent systems. [ABSTRACT FROM AUTHOR]

In the present study, the Sataun landslide was investigated along the National Highway-72 (NH-72) between Sirmauri Tal and Sataun towns of the Sirmaur district of Himachal Pradesh, Northwestern Himalaya, India. Geologically, the Sataun landslide is composed of Middle Siwalik sandstones, which are highly fractured and faulted due to the interaction of the active Sirmauri Tal Fault zone and the Malgi Fault at the site of the Sataun landslide. Through the geological field investigations, three unstable zones were identified, which are prone to landslides. A major failure along one of the unstable zones (Sataun landslide, Zone 1) occurred on the 9th of October 2019. The investigation of the Sataun landslide was carried out using geological, geomorphological, geotechnical, and kinematic analysis. A pre-landslide topography was used to analyse the slope stability using FEM (finite element modelling) technique. Geomorphological studies and field investigations suggest the presence of an active fault zone (Sirmauri Tal Fault zone) passing through the Sataun landslide zone. Grain size analysis demonstrates that the soil is non-cohesive poorly graded sandy soil and geotechnical parameters indicate low cohesion (0.17 kPa) and low angle of internal friction (33.09°). Pre-landslide slope modelling suggests a low factor of safety (0.76). Toe cutting by the Giri River, the presence of radial, transverse cracks on the landslide body, and tension cracks on the crown propose the active and progressive nature of the landslide. Although the role of active fault is the most crucial factor for the Sataun landslide failure, rainfall played a critical triggering role in the Sataun landslide. This study shows that the unstable condition of the Sataun landslide may trigger another event of similar or greater intensity in the near future; therefore, proper monitoring is required to mitigate this landslide. [ABSTRACT FROM AUTHOR]

The dynamic properties of soil obtained from the torsional simple shear test (TOSS) are assumed to be uniform throughout the specimen. For some exceptional soils, this may hold true, but for the most majority of soils that we examine, it is obviously not the case, and this level of non-uniformity depends on the conditions in which the soil was formed. In this paper, we discuss a method of modelling inherently non-uniform soil specimens by representing them with elements that have an elasto-plastic simple Tresca material model with different properties (Elastic young modulus and yield stresses). The combination of properties that can simulate the nonlinear behaviour of the soil is found and calibrated using a model of the TOSS test built in the finite element software Midas GTS NX. Furthermore, the influence of rigid inclusions in the soil is studied and the results show an increase in stiffness with the increasing percentage of inclusion in the soil. [ABSTRACT FROM AUTHOR]

Analysis and design of tunnels excavated in jointed rock mass is a challenging task. Situation aggravates when rock mass is found to experience a moderate or high squeezing. In this study, a novel numerical paradigm is presented for finite element analysis of tunnels excavated in squeezing ground. For this purpose, a tunnel model set is developed, namely Three Analysis Method (3AM). The 3AM involves three inter-connected models representing different tunnel construction stages. In this model, elastic–perfectly plastic behaviour of poor-quality rock mass is modelled by generalised Hoek–Brown criterion under biaxial in situ stress field. A case study of Maneri–Bhali Stage-I Hydro-electric Project (India) is investigated using this framework. Herein, tunnel support structure interaction responses are quantified in terms of tunnel convergence, stress components, ground-reaction curve, and support-characteristic curve. Results indicate that the 3AM is a realistic technique of tunnel simulation as it adopts the effect of tunnel convergence due to delay in support installation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature 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.)

Quantitative defect and damage reconstruction play a critical role in industrial quality management. Accurate defect characterisation in Infrared Thermography (IRT), as one of the widely used Non-Destructive Testing (NDT) techniques, always demands adequate pre-knowledge which poses a challenge to automatic decision-making in maintenance. This paper presents an automatic and accurate defect profile reconstruction method, taking advantage of deep learning Neural Networks (NN). Initially, a fast Finite Element Modelling (FEM) simulation of IRT is introduced for defective specimen simulation. Mask Region-based Convolution NN (Mask-RCNN) is proposed to detect and segment the defect using a single thermal frame. A dataset with a single-type-shape defect is tested to validate the feasibility. Then, a dataset with three mixed shapes of defect is inspected to evaluate the method's capability on the defect profile reconstruction, where an accuracy over 90% on Intersection over Union (IoU) is achieved. The results are compared with several state-of-the-art of post-processing methods in IRT to demonstrate the superiority at detailed defect corners and edges. This research lays solid evidence that AI deep learning algorithms can be utilised to provide accurate defect profile reconstruction in thermography NDT, which will contribute to the research community in material degradation analysis and structural health monitoring. [ABSTRACT FROM AUTHOR]

Large diameter, short monopiles are the preferred foundation type for offshore wind turbines. These piles demonstrate a rigid response with significant rotation of the pile base under ultimate lateral load. As traditional empirical p-y curves used in lateral loaded pile analysis have been derived from tests on small diameter onshore piles, there is some doubt about their applicability to rigid monopiles, particularly in view of the significant difference in the response of the pile base compared with a typical onshore pile. To address this issue, this paper reports on a unique series of field tests using instrumented driven pipe piles, complimented by numerical analysis, which was performed to examine explicitly the contribution of the pile base to the response under lateral load. The field tests, which included tests on pipe piles that had the sand plug removed to below pile tip level prior to testing, confirmed that the influence of the base on the lateral response for the tested 273- and 457-mm-diameter piles was negligible. Numerical analyses that were calibrated using the field test data showed that the contribution of the base to the lateral capacity of a monopile with a diameter as large as 10 m is negligible. Results also indicated that p-y curves are not affected by the length to diameter ratio and can be used to predict the response of monopiles in sand. [ABSTRACT FROM AUTHOR]

The impedance-matching mechanism of the ossicular chain of the middle ear is disrupted by erosion of the incus, warranting prosthetic intervention. The present-day practice of straight rigid-rod is not competent to restore the required level of natural motion attenuation and force amplification between the tympanic membrane and stapes-footplate. In this work, we use finite element simulation of anatomically accurate middle ear to evaluate the efficacy. We compare the performance of differently shaped incus-prosthesis, T, C, and S in particular, using simulation. We find that the S-shaped incus-prosthesis gives the best performance. We also prototyped the prosthesis and performed a preliminary cadaveric study. The finite element simulation combined with the ability to 3D-print has the potential for effective personalized surgical intervention. [ABSTRACT FROM AUTHOR]

The present contribution deals with the possibility of using the PI-Control method in order to perform a Hybrid Fire Test (HFT) with a force-controlled procedure (FCP). Such a method may be applied in two ways where the instantaneous error is calculated in term of displacement or in term of force. Like the displacement-controlled procedure (DCP), stability of the HFT results can be ensured by an appropriate design of the values of the gains matrix, which depends on the estimation of the initial stiffness of the Physical Substructure (PS) as well as the chosen value of the eigenvalues. This paper will demonstrate how it is possible to determine optimal parameters in order to ensure the stability of a HFT when using such a method. In addition, it will be shown that, on the contrary to the recommendations for the use of the PI-Control method with the DCP, the initial stiffness of the PS should be underestimated rather than overestimated when the FCP is used. For illustrative purpose, several virtual HFTs have been implemented and analysed. [ABSTRACT FROM AUTHOR]

The practical application of cold-formed high strength steel is becoming increasingly popular in structural engineering due to its great efficiency and cost effectiveness. However, cold-formed steel sections are usually associated with high slenderness, hence are susceptible to buckling failure. Consequently, the buckling resistance of steel struts made of cold-formed high strength steel must be determined with carefulness, particularly for complex compound sections. To this end, the present paper aims at investigating the behaviour of back-to-back channel sections made of S700 steel with a characteristic yield strength of 700 MPa. Compressive tests on such members are conducted for the purpose of validating the finite element models. Subsequently, a numerical parametric analysis is carried out on the buckling resistance of axially loaded cold-formed steel back-to-back channel sections, using the previously validated numerical modelling approach. In particular, the effects of stiffeners and number of bolts on the buckling resistance are investigated. Furthermore, the results of the parametric analysis are also compared with the codified buckling resistance determined based on the effective width method adopted in Eurocode 3 Part 1–3, in order to evaluate the reliability of the standardised design method for buckling resistance. [ABSTRACT FROM AUTHOR]

Aims: In the finite element method, the mechanical behaviour of plant roots has been modelled by solid element or embedded beam element (EBE). However, the former is computationally expensive, whereas the latter is unable to capture the root pull–out failure mode. In this study, we modified the constitutive stress–strain relationship of an existing EBE to calculate uprooting resistance by considering the root–soil interfacial shearing and the strength decline as root pulls out. Methods: We introduced an elasto–softening constitutive law to describe the root–soil interface interaction and an improved damage model to capture post–peak softening behaviour in EBE. We validated the EBE against three case studies. Finally, we conducted parametric analysis to study how root geometries, morphologies and soil saturation affect the uprooting response. Results: Our new model captures the pre–peak uprooting behaviour up to the peak pull–out force (Pul). Root systems that failed by pull–out mode always had lower Pul than those that failed by breaking, irrespective of the root morphology. Reduction of soil effective stress following soil saturation always reduced Pul and could change the root failure mode, depending on the anchorage length and root–soil contact surface area. Conclusions: Root–soil mechanical interaction and root failure mode, including pull–out and breakage, can now be modelled with more accuracy. We show the importance of considering soil moisture variation, which translates to variations in root reinforcement effects. The reinforcement effectiveness of deep–rooted systems can be halved, and the root failure mode can switch from breakage to pull–out, following soil saturation and reduction of soil effective stress. [ABSTRACT FROM AUTHOR]

The main novelty of this study is producing Ultra High-Performance Self Compacting Mortar (UHPSCM) incorporated Recycled Steel Fibre (RSF) from waste tires. For this purpose, different mix compositions including 0%, 1%, and 3% RSF content in terms of volume were proposed. Self-compacting ability was assessed using mini-cone tests, while nondestructive testing has been used to evaluate the effect of RSF inclusion on the compaction of UHPSCM constituent materials. Mechanical performances were investigated using compression and unnotched flexural tests. Residual flexural strength in both service limit state (SLS), ultimate limit state (ULS), and two equivalent flexural strengths were evaluated under notched flexural tests and analysed using statistical approaches. Concrete Damage Plasticity (CDP) has been employed for the analysis behaviour of developed mortars under different loadings. Additionally, an element deletion approach was used to evaluate the fracture of UHPSCM under compression and flexural loadings. The experimental results showed that adding 1% and 3% of RSF resulted in decreasing workability by 3% and 22%, respectively. Improving compressive strength by 16% and 22% and flexural by 7% and 8% were noticed in the case of samples with 1% and 3% fiber, respectively, in 28 days. In spite of the significant improvement of post-cracking behaviour of samples with 3% of RSF, this behaviour was insignificant for the samples with 1% of RSF. However, with less amount of fibre inclusion, brittle failure can be altered to ductile failure. Moreover, the behaviour of the tested specimens under different loadings was successfully predicted using Finite Element (FE) simulations. [ABSTRACT FROM AUTHOR]

The dynamic behavior of osseointegrated implants can be used for the non-invasive evaluation of the condition of the bone-implant-interface (BII). The Advanced System for Implant Stability Testing (ASIST) is a vibration measurement system that relies on an impact technique and an analytical model to compute the interface stiffness and the ASIST stability coefficient ([Formula: see text]). The objective of this work is to develop a finite element (FE) model capable of capturing the dynamic behaviour of the bone-anchored hearing aid under the ASIST loading condition. The model was validated with previously collected in vitro and in vivo data which were compared to the model's acceleration responses and [Formula: see text] scores. Similar acceleration responses were obtained, and the maximum absolute differences in [Formula: see text] scores between the FE model and the in vitro and in vivo data were 1.15% and 5.48% respectively. The model was then used to show the existence of a relationship between the rod's acceleration response and the BII stress field. Finally, the model was used to interpret the factors that affect the stiffness parameters of the ASIST analytical model. The interface stiffness and the system's dynamic properties were more influenced ([Formula: see text]) by the BII material and friction coefficient compared to the implant geometry. In this work, a finite element model of the bone anchored hearing aid was used to simulate the dynamic behaviour of the bone-implant system under the ASIST's loading conditions. The model was first validated with previously collected experimental and clinical results. The validated model was then used to study the relationship between the impact rod's acceleration response and the response at the bone implant interface. Finally, the model was used to formulate a better understanding on the influencing factors on the interface stiffness. [ABSTRACT FROM AUTHOR]

Distal interphalangeal joint arthrodesis is a frequent surgical operation performed to treat severe arthritis. Nevertheless, the angle selected when fusing the joint is arbitrarily chosen without any quantified data concerning its mechanical effects, thus preventing the optimal choice for the patient. In the current study, we realized an experiment and developed a numerical model to investigate the effect of fusion angle on the biomechanics of adjacent non-operated joints. Six participants performed a pinch grip task while arthrodesis was simulated with a metal splint. Kinematic and force data were recorded during this task and used in a biomechanical model to estimate contact pressures in adjacent joints. The biomechanical model involved combining a multibody system and a finite element method. Results showed that the angle of any distal interphalangeal joint arthrodesis influences index finger kinematics and maximal grip force in several participants. For one participant, in the arthrodesis simulation, we observed an increase of 1.9 MPa in the proximal interphalangeal joint contact pressure. Our results provide quantified information about the biomechanical consequences of this surgical operation and its potential long-term effects. [ABSTRACT FROM AUTHOR]

A structural health monitoring system was installed on the 60-year-old Diefenbaker Bridge, located in Prince Albert, Saskatchewan, Canada, to investigate in-situ bridge behaviours, such as the degree of composite action, lateral load distribution, and dynamic load influence. The 304 m long, seven span bridge consists of two separate fracture critical superstructures, each comprising a cast-in-place concrete deck supported by two non-composite welded wide flange girders. Previous studies, based solely on a structural analysis, concluded that the connection of the lateral bracing to the girder web had less than 5 years of remaining fatigue life. Due to the uncertainty involved in this calculation, the data acquired from 6 months of field monitoring were used to define the structure's response to live loading, and to calibrate a finite element model that was used to characterize the three-dimensional stress state at that connection. It was found that unexpected composite action, increased load sharing between the girders, and minimal dynamic load influence exist in the bridge. Results were compared with those obtained using the Canadian Highway Bridge Design Code (CAN/CSA S6–14). Based on the monitoring results, it was concluded that costly improvements to the connection detail were not required, since the remaining fatigue life was estimated to be at least 52 years. In addition, it was found that the exterior girders are more heavily loaded than the interior girders, and the northbound structure is more heavily loaded than the southbound, permitting the location of the most critical connection for fatigue life to be identified. [ABSTRACT FROM AUTHOR]

The article discusses the features of radial shear rolling (RSR) of the aluminum alloy Al–Mg–Sc. The modeling of the RSR process by the finite element method in the QForm 3D program with variation of the elongation ratio per pass and the rolling speed has been implemented. On the basis of the results obtained, a study of the temperature field of the rod in the deformation zone has been carried out taking into account the cyclic deformation and the configuration of the flow trajectories. It is found that changes in the temperature field of the rod in the deformation zone are determined by the difference in the trajectory flow of the metal in the surface layers and in the axial zone. When the elongation ratio is varied from 1.6 to 2.4, heating occurs inconsistently from the center to the surface. The largest increase occurs for an area that is approximately 0.3R from the surface. For the axial zone, the temperature change in the deformation zone occurs smoothly and with an insignificant temperature difference of 5–10°C. The temperature on the surface of the rod has the greatest temperature fluctuations, which are explained by deformation heating and simultaneous contact with a cold roll during each deformation cycle. With a decrease in the rolling speed, a picture of the distribution of the temperature field of the rod in the deformation zone is observed, when the temperature of the central layers exceeds the surface temperature. Because of the long contact time of the rod with the roll, the surface temperature fluctuates up to 40–50°C with each deformation cycle. With an increase in the rolling speed, the amplitude of temperature fluctuations on the surface decreases, and the deformation heating increases. The obtained data on the relationship of controlled technological parameters with a change in the temperature field of the rod can be useful in the design of technological modes of rolling. [ABSTRACT FROM AUTHOR]

Nonlinear time domain numerical approaches together with elasto-plastic effective stress soil constitutive models are nowadays available to geotechnical researchers and practitioners interested in geotechnical earthquake engineering. The use of such advanced two- and three-dimensional schemes allows the analysis and design of complex geotechnical structures within a performance-based framework, considering the build-up of excess pore water pressure during the earthquake, dynamic interaction between the soil deposit and the above surface buildings and infrastructures and effects of multi-directional seismic loading. Within this context, the paper focuses on the dynamic finite element (FE) method and presents a review of the key ingredients governing its predictive capabilities. These include i) the description of the fully coupled solid–fluid interaction formulation and time integration, ii) the calibration of Rayleigh damping and the soil constitutive model parameters, iii) prescription of the boundary conditions for the generated mesh and iv) input motion selection/scaling strategies. For each of the above points, the paper summarises the current knowledge and best practice, with the aim of providing protocols for a confident application of nonlinear FE schemes to evaluate the performance of critical geotechnical infrastructures. Useful hints to promote familiarity of advanced nonlinear soil dynamic analysis among geotechnical practitioners and to indicate areas for further improvement are also highlighted. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature 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.)

Estimation of tunnelling-induced surface settlements requires empirical, analytical, or finite element analysis methods to be applied. Tunnelling method and construction sequence highly influence the surface settlements and require appropriate consideration in the analyses. In this research, the effect of single tunnel construction in soft clays, stiff clays, loose sand, and dense sand was simulated using Plaxis 2D finite element software. The results were interpreted to obtain maximum settlement at the ground surface. The effect of varying tunnelling depth, diameter, and volume loss on the maximum ground surface settlement and the location of inflection point along the ground surface settlement curve was investigated. Based on the results obtained, a set of equations for maximum surface settlement and inflection point were developed that provides a method of evaluation for maximum surface settlement and inflection point variation with respect to the tunnel diameter, depth, and volume loss. The multivariable prediction equation for maximum surface settlement is validated to be very successful overall for tunnelling in most soils, and the analyses were calibrated using field data from various tunnelling projects presented in the literature. [ABSTRACT FROM AUTHOR]

Background: Fatigue failure criteria for fibre reinforced polymer composites used in the design of marine structures are based on the micromechanical behaviour (e.g. stiffness properties) of their constituents. In the literature, there is a lack of information regarding the stiffness degradation of fibres, polymer matrix and fibre/matrix interface regions affected by environmental fatigue. Objective: The aim of present study is to characterize the stiffness properties of composite constituents using the nanoindentation technique when fatigue failure of composites is due to the combined effect of sea water exposure and cyclic mechanical loads. Methods: In the present study, the nanoindentation technique was used to characterize the stiffness properties of composite constituents where the effects of neighbouring phases, material pile up and viscoplasticity properties of the polymer matrix are corrected by finite element simulation. Results: The use of finite element simulation in conjunction with nanoindentation test data, results in more accurate estimation of projected indented area which is required for measuring the properties of composite constituents. In addition, finite element simulation provides a greater understanding of the stress transfer between composite constituents during the nanoindentation process. Conclusions: Results of nanoindentation testing on the composite microstructure of environmentally fatigue failed composite test coupons establish a strong link to the stiffness degradation of the fiber/matrix interface regions, verifying the degradation of composite constituents identified by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis. [ABSTRACT FROM AUTHOR]