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Thin-walled tubular deployable composite boom (DCB) has gained significant attention due to its lightweight, simple structure and high packaging efficiency. The experimental and numerical simulation methods were employed in this paper to investigate the folding behavior of the DCB. Using T700/epoxy unidirectional reinforced prepreg as raw material, DCB specimens were prepared by the vacuum bag method. To complete the folding experiments of DCB specimens, a folding mechanism was designed and manufactured. Folding experiments of DCB specimens were conducted and folding moment versus rotational displacement curves were measured. In addition, a Finite Element Model (FEM) was established to predict the folding behavior of the DCB. Different failure criteria were considered in the numerical analysis, including the Tsai‐Hill criterion and maximum stress criterion. Prediction results using the FEM were compared with experimental results, and both sets of results were in good agreement. It is shown that the DCB can achieve the folding function without failure. The research results in this paper are of great significance to the practical engineering application of the DCB. [Display omitted] • Six tubular deployable composite boom specimens and a precise folding mechanism were designed and prepared. • Folding experiments were conducted to measure the folding moment and rotational displacement curves. • A finite element model for predicting the folding behavior of the tubular deployable composite boom was established. [ABSTRACT FROM AUTHOR]

Based on the classical grid theory and related regulations, a structure model of a fiber-wound composite gas cylinder was designed in this paper. Based on the design results, a finite element model of a fully wound composite cylinder of an aluminum alloy inner liner with a working pressure of 35 MPa was established based on the ABAQUS software, and its stress distribution under working pressure and minimum burst pressure was analyzed. According to engineering experience, the pressure tolerance of composite cylinders can be improved by proper autofrettage pressure before working pressure, so the influence of autofrettage pressure was analyzed in this paper. The optimum autofrettage pressure was selected by setting the autofrettage gradient, and damage analysis was carried out on the cylinder with nominal working pressure of 35 MPa based on the Hashin failure criterion. The results show the initial damage sequence: matrix stretching occurs before the fiber stretching, and the damage generally starts from the spiral-wound layer. The tensile damage first appears in the transition section between the head and the barrel body, and the damage of the spiral-wound layer develops from the inner layer of the wound layer to the outer layer, while the damage of the circumferentially wound layer develops from the outer layer to the inner layer. [ABSTRACT FROM AUTHOR]

The objective of the paper is to demonstrate the potential of the localizing gradient damage model in size effect simulations. Three different gradient activity functions for variable internal length scale are considered. Numerical simulations for an unnotched beam under three-point bending are referred to the experiment performed by Grégoire et al. (2013). A confrontation with the conventional gradient damage model as well as mesh sensitivity studies are also presented. It is proved that the localizing gradient damage model with different variants of the gradient activity function can reproduce the size effect quite reasonably. [ABSTRACT FROM AUTHOR]

In the process of intelligent compaction of roadbeds, the water content of the roadbed is one of the important influencing factors of compaction quality. In order to analyze the effect of water content on the compaction quality of roadbeds, this paper is developed by secondary development of Abaqus finite element numerical simulation software. At the same time, the artificial viscous boundary was set to eliminate the influence of boundary conditions on the results in the finite element modeling process, so that the numerical simulation can be refined to model. On this basis, the dynamic response analysis of the roadbed compaction process is performed on the finite element numerical simulation results. This paper established the correlation between compaction degree and intelligent compaction index CMV (Compaction Meter Value) and then analyzed the effect of water content on the compaction quality for the roadbed. The results of this paper show that the amplitude of the vertical acceleration is almost independent of the moisture content, and the vertical displacement mainly occurs in the static compaction stage. The vertical displacement changes sharply in the first 0.5 s when the vibrating wheel is in contact with the roadbed. The main stage of roadbed compaction quality increase is before the end of the first compaction. At the end of the first compaction, the roadbed compaction degree increased rapidly from 80% to 91.68%, 95.34% and 97.41%, respectively. With the increase in water content, the CMV gradually increased. At the end of the second compaction, CMV increased slightly compared with that at the end of the first compaction and stabilized at the end of the second compaction. The water content of the roadbed should be considered to be set slightly higher than the optimal water content of the roadbed by about 1% during the construction of the roadbed within the assumptions of this paper. [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate (PMMA) polymer is widely used in various fields today. In order to reveal the structural impact performance of PMMA materials in underwater engineering thoroughly, this paper firstly proposed a simplified plate model for a spherical shell hull under concentrative impact loading. Then, to simulate the hyper-elastic material properties of PMMA in the impact process, the Johnson–Cook constitutive model and damage failure model were adopted. And the least squares method was used to confirm accurately the J–C constitutive and damage failure model parameters of PMMA through material test data. Moreover, the dynamic process of the steel bullet impacting the PMMA plate structure was analyzed by the finite element software ABAQUS. The calculation results show that the numerical simulation results in this paper have a good convergence, and the residual velocities at different initial velocities and thicknesses of plates are in good agreement with the experimental test data. Therefore, the feasibility and accuracy of the impact analysis of PMMA structures based on J–C constitutive and damage failure models in this paper are verified accordingly. Finally, based on the presented finite element model, the structure response and the variation of residual velocity of the bullet with the PMMA plate thickness was analyzed in depth; that is, the results show that the residual velocity of the bullet has a certain linear relationship with the thickness, even in an underwater environment, and even in an underwater environment will increase both with a thicker structure or a higher pressure. [ABSTRACT FROM AUTHOR]

In order to analyze the impact angle of pick cutter, the angle of alloy head and the cutting line spacing on rock breaking effect, the three-dimensional model of rock cutting by pick cutter was established by solidworks, and the three-dimensional finite element model of rock breaking by pick cutter based on penetration failure and compression damage was established by using dynamic simulation software ANSYS/LS-DYNA. For the drum with a diameter of 1200 mm, a length of 900 mm and a rotational speed of 30 rot/min, when the impact angles of the picks are 30°, 37°, 45° and 52°, the angles of the alloy heads are 70°, 80°, 90° and 100°, and the intercept distances are 250 mm, 275 mm, 300 mm and 325 mm, the rock breaking simulation based on the finite element analysis software is carried out, and the load and specific energy consumption of the drum are obtained. Finally, through the analysis and comparison, the existing parameters are optimized, and a better parameter model is obtained. [ABSTRACT FROM AUTHOR]

The concept of "Industry 4.0" encourages the use of automated manufacturing processes and the use of advanced technological systems. Some of the most fundamental needs of the Fourth Industrial Revolution can only be met with the help of additive manufacturing. However, the mechanical behavior and reliability of additive-manufactured components are hardly recognized. This paper provides a systematic review of metal additive manufacturing technologies, materials, lattice structures, and fatigue properties as well as the development of numerical simulations. The current state of development in metal alloys and the optimization of cellular structures were presented. In addition, this paper discussed the main challenges in numerical simulation methods, their validation with experimental results, and the limitations of commercial software used. Overall, this paper provides an overview of metal additive manufacturing as well as a survey of its simulation software development to optimize several parameters in industrial and academic research fields. The results were critically analyzed and provided a benchmark for future research and development. [ABSTRACT FROM AUTHOR]

Explosion models based on Finite Element Analysis (FEA) can be used to simulate how a warhead fragments. However their execution times are extensive. Active protection systems need to make very fast predictions, before a fast attacking weapon hits the target. Fast execution times are also needed in real time simulations where the impact of many different computer models is being assessed. Hence, FEA explosion models are not appropriate for these real-time systems. The research presented in this paper delivers a fast simulation model based on Mott's equation that calculates the number and weight of fragments created by an explosion. In addition, the size and shape of fragments, unavailable in Mott's equation, are calculated using photographic evidence and a distribution of a fragment's length to its width. The model also identifies the origin of fragments on the warhead's casing. The results are verified against experimental data and a fast execution time is achieved using uncomplicated simulation steps. The developed model then can be made available for real-time simulation and fast computation. [ABSTRACT FROM AUTHOR]

Cracking failure of cement-treated base (CTB) has always been the concern of highway constructors. Mesoscale cracking analysis is an important means to study the damage degradation mechanism, which is difficult to be characterized by experimental techniques alone. The objective of this paper is to develop a random aggregate modelling method to simulate the mesoscopic cracking of CTB material. A minimum rectangle area method was proposed to calculate the polygon aggregate size, which is closer to the sieving analysis than the average radius method. A buffer zone method was proposed to determine the distance between randomly generated polygon aggregates. Based on the proposed random algorithm, finite element method (FEM) was adopted to build the mesoscopic model of CTB including aggregate, mortar, interfacial transition zone (ITZ) and air voids. Laboratory tests were conducted to validate the numerical model. Then the sensitivity analyses were conducted to study the influencing factors on cracking behavior. The simulation results indicate that the higher aggregate content and the finer gradation lead to the increase of ITZ, thus reducing the cracking resistance of the CTB material. Low porosity content is able to significantly reduce the stress concentration and thus improves the cracking resistance. The research results of this paper could be used to guide the crack resistant design of CTB material. [ABSTRACT FROM AUTHOR]

One-dimensional fourth-order boundary value problems (BVPs) play a critical role in engineering applications, particularly in the analysis of beams. Current numerical investigations primarily concentrate on homogeneous boundary conditions. In addition to its high precision advantages, the Hermite finite element method (HFEM) is capable of directly computing both the function value and its derivatives. In this paper, both the cubic and quintic HFEM are employed to address two prevalent non-homogeneous fourth-order BVPs. Furthermore, a priori error estimations are established for both BVPs, demonstrating the optimal error convergence order in H 2 semi-norm and L 2 norm. Finally, a numerical simulation is presented to validate the theoretical results. [ABSTRACT FROM AUTHOR]

The goal of this paper is to use the finite element method and computer simulation to prove the effectiveness in assessing the fire resistance of building construction elements, specifically on the example of the fire resistance of fire doors. For that purpose, data from the building where fire doors with defined characteristics were installed were used. For simulation purposes, numerical modelling with thermal and structural analysis will be used. In this way, the parameters of the temperature distribution on the fire door and the contact material due to fire will be obtained, as well as the distribution of strain and stresses, which will indicate the fire resistance of the used structure. Computer simulation with numerical modelling offers a number of advantages both in the speed of providing results of a larger number of variants of the simulation model and in the accuracy of the results obtained once the model is calibrated. Also, the mentioned type of predicting the effect of fire can be applied to other elements of the structure of the construction object, which can significantly influence the decision-making that will prevent the negative consequences of the occurrence of a possible fire. [ABSTRACT FROM AUTHOR]

This paper reviews numerical methods used to simulate desiccation cracks in clayey soils. It examines five numerical approaches: Finite Element (FEM), Lattice Boltzmann (LBM), Discrete Element (DEM), Cellular Automaton (CAM), and Phase Field (PFM) Methods. The paper presents a simplified description of the methods, including their basic numerical formulations. Several factors such as the multiphase nature of soils, heterogeneity, nonlinearities, coupling, scales of analysis, and computational aspects are discussed. The review highlights the characteristics, strengths, and limitations of each method. FEM shows a good capacity to deal with the thermo-hydromechanical behavior of clays when drying that complement well with the ability of DEM to deal with particle interactions as well as LBM, PFM, and CAM to deal with complex crack patterns. The article concludes by reviewing the integration of multiple numerical methods to enhance the simulation of desiccation cracks in clayey soils and proposing what is the best option to continue improving the study of this problem. [ABSTRACT FROM AUTHOR]

Coal-based carbon foam (CCF) has broad application prospects in aerospace, composite material tooling and other fields. However, the lack of failure criteria limits its promotion. In previous studies, the failure criteria of similar materials were proposed, but there are some limitations. This paper proposes improved failure criteria based on macro-mechanical tests. Furthermore, uniaxial and multiaxial loading tests were carried out to obtain accurate failure criteria of CCF. Finally, 3-points bending tests of the CCF sandwich structure were conducted and their finite element models (FEMs) were established. The CCF test results show that the mechanical properties of CCF are transversely isotropic. The failure criteria in this paper can accurately predict the stress when the CCF fails. The error band boundary formula caused by the dispersion of the material were also given. The maximum load Pmax calculated by the failure surface (3684 N) was only 4.7% larger than the mean value measured by the test (3518 N), and all of the Pmax measured by the test (3933 N, 3640 N, 3657 N, 3269 N, 3091 N) were between the maximum value (4297 N) and minimum value (3085 N) calculated by the error band boundary formula, which means that the failure criteria have good precision. [ABSTRACT FROM AUTHOR]

This paper does some research and discussion on the finite element analysis of a building structure, especially the computer graphics simulation method in building structure simulation. Moreover, with the support of BIM technology and computer finite element simulation technology, this paper constructs a building structure simulation system and analyzes the building structure simulation system based on actual conditions such as building structure and stress load. In addition, this paper improves the traditional structural analysis algorithm and designs experiments to evaluate the effect of the method proposed in this paper and analyze the data in the form of simulation to compare the validity of the test results. Finally, an experiment is designed to evaluate the data processing capability of the test system in this paper. The experimental analysis results verify the effectiveness of the method in this paper, which can provide relevant theoretical references for subsequent building structure simulation. [ABSTRACT FROM AUTHOR]

The paper deals with theoretical description and numerical simulations of internal sources of heating/cooling in large strain thermo-elasticity and thermo-elasto-plasticity. The attention is paid to metallic materials which undergo cooling in the elastic range and heating during plastic yielding. Theoretical description can be derived from thermodynamic considerations based on the first and second laws of thermodynamics and assumed forms of the Helmholtz free energy. Numerical simulations within the Finite Element Method are performed for a uniaxial tension test and elongation of a dogbone-shape sample. For the latter specimen, a comparison with experimental results is performed, and good agreement is obtained. [ABSTRACT FROM AUTHOR]

Three-dimensional porous scaffolds are substitutes for traditional bone grafts in bone tissue engineering (BTE) applications to restore and treat bone injuries and defects. The use of computational modelling is gaining momentum to predict the parameters involved in tissue healing and cell seeding procedures in perfusion bioreactors to reach the final goal of optimal bone tissue growth. Computational modelling based on finite element method (FEM) and computational fluid dynamics (CFD) are two standard methodologies utilised to investigate the equivalent mechanical properties of tissue scaffolds, as well as the flow characteristics inside the scaffolds, respectively. The success of a computational modelling simulation hinges on the selection of a relevant mathematical model with proper initial and boundary conditions. This review paper aims to provide insights to researchers regarding the selection of appropriate finite element (FE) models for different materials and CFD models for different flow regimes inside perfusion bioreactors. Thus, these FEM/CFD computational models may help to create efficient designs of scaffolds by predicting their structural properties and their haemodynamic responses prior to in vitro and in vivo tissue engineering (TE) applications. [ABSTRACT FROM AUTHOR]

This paper aims to elucidate the clear visibility of attenuating seismic waves (SWs) with forest trees as natural metamaterials known as forest metamaterials (FMs) arranged in a periodic pattern around the protected area. In analyzing the changeability of the FM models, five distinct cases of "metawall" configurations were considered. Numerical simulations were conducted to study the characteristics of bandgaps (BGs) and vibration modes for each model. The finite element method (FEM) was used to illustrate the generation of BGs in low frequency ranges. The commercial finite element code COMSOL Multiphysics 5.4a was adopted to carry out the numerical analysis, utilizing the sound cone method and the strain energy method. Wide BGs were generated for the Bragg scattering BGs and local resonance BGs owing to the gradual variations in tree height and the addition of a vertical load in the form of mass to simulate the tree foliage. The results were promising and confirmed the applicability of FEM based on the parametric design language ANSYS 17.2 software to apply the boundary conditions of the proposed models at frequencies below 100 Hz. The effects of the mechanical properties of the six layers of soil and the geometric parameters of FMs were studied intensively. Unit cell layouts and an engineered configuration for arranging FMs based on periodic theory to achieve significant results in controlling ground vibrations, which are valuable for protecting a large number of structures or an entire city, are recommended. Prior to construction, protecting a region and exerting control over FM characteristics are advantageous. The results exhibited the effect of the 'trees' upper portion (e.g., leaves, crown, and lateral bulky branches) and the gradual change in tree height on the width and position of BGs, which refers to the attenuation mechanism. Low frequency ranges of less than 100 Hz were particularly well suited for attenuating SWs with FMs. However, an engineering method for a safe city construction should be proposed on the basis of the arrangement of urban trees to allow for the shielding of SWs in specific frequency ranges. [ABSTRACT FROM AUTHOR]

The safe and stable operation of the radial gate is highly essential for hydropower stations. As the dynamic load of gate, water flow generally causes the irregular distribution of strength, stiffness, and the stability of the gate structure. Traditional simulation technology is usually used to investigate the impact of water flow on gate structure; however, there is a lack of integration and interaction of building information modeling (BIM) and numerical simulation technology to study this issue. Therefore, this paper proposed a computational framework combing BIM and numerical simulation to calculate and analyze the large complex hydraulic radial steel structure. Firstly, the 3D model of the radial gate was established by MicroStation2020, then, the finite element model was output by using it. Secondly, the change laws of strength, stiffness, and stability of the radial gate were analyzed by Ansys-Workbench2020R2 under different opening degrees. The numerical simulation results show that the maximum equivalent stress value was 142.19 MPa, which occurred at the joint between the lower longitudinal beam and the door blade. The maximum deformation was 3.446 mm, which occurred at two longitudinal beams' middle in the lower part of the panel. When the opening degree is 0.0 m–9.0 m, the natural vibration frequency increases irregularly with the increase in the opening of the gate. Three main vibration modes of the gate vibration were obtained. It proves that it is feasible to analyze the structural performance of radial gates by using BIM and numerical simulation. Finally, the BIM and numerical simulation information management process was established to make the simulation results more valuable. This study expands the application value of BIM and provides a new research idea for large complex hydraulic steel structural analysis. The information management process described in this research can serve as a guide for gate operation and maintenance management. [ABSTRACT FROM AUTHOR]

Vibrating flip-flow screens are widely employed in the deep screening processes of coal washing, solid waste treatment, metallurgy, and other fields, playing a crucial role in enhancing product quality and production efficiency. The screen surface and material movement of vibrating flip-flow screens are highly complex, and there is currently insufficient understanding of their screening mechanism, limiting further optimization and application. In this paper, the Discrete Element Method (DEM), Finite Element Method (FEM), and Multi-Body Dynamics (MBD) were integrated to establish a numerical coupling model for vibrating flip-flow screens, considering material loads, screen surface deformation, and screen machine dynamics. The Response Surface Method was utilized to analyze the significant impact of relative amplitude, tension amount, amplitude of driving screen frame, vibration frequency, and screen surface inclination on screening efficiency and material velocity. The results indicate that the most significant factor influencing the screening of flip-flow screens is the screen surface inclination. Based on a BP neural network, a five-degree-of-freedom inclination surrogate model for flip-flow screens was established. The whale algorithm was employed for multi-objective optimization of the surrogate model, resulting in a screen surface inclination distribution that meets the requirements of different operating conditions. [ABSTRACT FROM AUTHOR]

The trend towards electrification in mobility has led to the increased use of silicon carbide (SiC) semiconductors. These semiconductors are more efficient but also present challenges related to electromagnetic interference (EMI) due to their higher voltage derivatives. This paper introduces a new high-frequency impedance model for electrical machines. The proposed model distinguishes itself from existing approaches by being entirely derived from Finite Element Method (FEM) simulations, which include capacitances in the magnetic simulation. This approach achieves a balance between computational efficiency and high accuracy across the entire frequency spectrum, ranging from 100 Hz to 50 MHz. The model provides valuable insights during the design phase and was rigorously validated using data from 28 samples of an industrial machine. [ABSTRACT FROM AUTHOR]

The warm-forging technology of the spiral bevel gear (873 K–1073 K) was studied. Based on the rigid–plastic finite element method, a numerical simulation was carried out by using DEFORM V11.0 software to explore the influence of different process parameters on gear-forming quality and forming force in the process of warm forging. Taking into account the complexity of the geometry of spiral bevel gears and the diversity of the influence factors in the forging process, as determined through nine groups of numerical simulation experiments, this paper systematically analyzed the influence law of different forging speeds, die preheating temperatures, friction factors and workpiece heating temperatures on the effective stress and strain of spiral bevel gears. The best combination of process parameters with minimum forging force was obtained via the orthogonal experiment, which provides a theoretical basis for the optimization design of the precision forging process of spiral bevel gears and also provides a new idea for studying the precision-forging–forming process of other complex parts. [ABSTRACT FROM AUTHOR]

The first paper of this two-part series discussed the development of a novel lightweight 3D wood dowel-reinforced glass epoxy hybrid composite material (3DdrFRP) and its manufacturing procedures. It also experimentally compared the performance of scaled utility poles made from conventional 2D E-glass epoxy and 3DdrFRP materials. In the second part, the development of robust, efficient, and fairly accurate nonlinear finite element (FE) models is outlined. The models are calibrated based on experimental results and used to simulate the performance of equivalent 2D and 3D poles, proving the integrity of the numerical models. Additionally, a simplified analytical calculation method is developed for practicing engineers to evaluate the stiffness of 3D-DrFRP poles fairly accurately and quickly. [ABSTRACT FROM AUTHOR]

This paper presents an efficient and reliable approach to study the low-velocity impact response of woven composite shells using 3D finite element models that account for the physical intralaminar and interlaminar progressive damage. The authors' previous work on the experimental assessment of the effect of thickness on the impact response of semicylindrical composite laminated shells served as the basis for this paper. Therefore, the finite element models were put to the test in comparison to the experimental findings. A good agreement was obtained between the numerical predictions and experimental data for the load and energy histories as well as for the maximum impact load, maximum displacement, and contact time. The use of the mass-scaling technique was successfully implemented, reducing considerably the computing cost of the solutions. The maximum load, maximum displacement, and contact time are negligibly affected by the choice of finite element mesh discretization. However, it has an impact on the initiation and progression of interlaminar damage. Therefore, to accurately compute delamination, its correct definition is of upmost importance. The validation of these finite element models opens the possibility for further numerical studies on of woven composite shells and enables shortening the time and expenses associated with the experimental testing. [ABSTRACT FROM AUTHOR]

This paper proposes a new flexible and microscale roll gap control technology to obtain a stronger strip flatness control ability. According to the principle of microscale roll gap control technology, an electromagnetic control rolling mill with the function of roll profile control and large diameter ratio rolling is designed and built. To analyze the flatness control ability, a comprehensive finite element model (FEM) is established, and an indentation experiment and a rolling experiment are carried out. The simulation results show that under different rolling forces and tensions, the average quadratic crown control ability is more than 40 μm, and the average quartic crown control ability is more than − 3 μm. The control ability increment of the quadratic crown is greater than that of the quartic crown. In the indentation experiment, a stable roll profile can be achieved by PID control after reaching the target roll profile. Increasing the regulation amount can change the strip crown from positive to negative. Even under high rolling force conditions, microscale roll gap control technology can also realize a strip crown adjustment of 19.5 to 0.5 μm. Moreover, this technology can adjust the strip shape from edge waves to non-waves and middle waves in the rolling experiment. In this paper, the feasibility of using this technology to adjust the roll gap shape has been verified, and we demonstrate that the roll gap control goal of uniform transverse size distribution can be achieved. [ABSTRACT FROM AUTHOR]

With the progressive promotion of BIM technology in collaborative design and engineering data management, there are large amounts of project information available for intelligent construction, engineering computation and design optimization. In the construction of subway station, BIM technology is still not mature and the engineering design is generally separate from the engineering safety evaluation. Thus, this paper proposed a technology that integrates BIM and numerical simulation (BIM-FEM/FDM integrated technology) to solve the problem of separation between engineering design and computation. A three-dimensional parametric modeling of subway station excavation was first carried out using the Revit® modeling software. Afterward, a FEM/FDM-process oriented data conversion interface was developed to extract and process the critical information from the parametric BIM model for numerical simulation. Then, under the impetus of an auto-simulation interface, the safety evaluation of subway station excavation was realized automatically and visualized graphically. The research of the BIM-FEM/FDM integrated technology presented in this paper has established a supporting platform to achieve the integration of BIM-based design and safety evaluation for subway station excavation. [ABSTRACT FROM AUTHOR]

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The service performance of tunnel lining is affected by crack properties and development states. In this paper, numerical simulation models were established to investigate the mechanics characteristics and safety performance for lining structures under different cracks based on the extended finite element method (XFEM). Analyze multiple quantitative factors in simulation, including changes in crack location, crack length, and crack distribution range in the lining structure. The axial force and bending moment of the preset cracks in the lining structures were first studied. The maximum safety factor attenuation rate ( D k m a x ) was proposed to analyze the impact of longitudinal and annular cracks on the safety performance. The axial force at the vault of the lining arch is the most significantly affected by the combined longitudinal cracks at multiple locations. When the length of a longitudinal crack increases from 1 m to 6 m, the axial force value at the crack point decreases by 33.77%, 36.15%, and 11.32%. However, the bending moment value increases by 4.47 times, 2.50 times, and 1.69 times. Under the influence of longitudinal cracks in an "arch crown + arch shoulder", "arch crown + arch waist", and "arch crown + arch shoulder + arch waist", the axial force in the arch vault increased by 21.55%, decreased by 17.52%, and decreased by 13.45%. The distribution pattern of the bending moment under the influence of circumferential cracks shows convexity at the arch shoulder and arch foot, and concavity at the arch waist and side walls. The safety factor scatter curve with longitudinal cracks shows a gradual transition from a "W" shape to a "U" shape. The safety factor curve with circumferential cracks presents an approximately symmetrical wave-shaped distribution. [ABSTRACT FROM AUTHOR]

Groundwater plays an essential role in stabilizing underground structures. However, hydrostatic uplift forces from groundwater can create safety hazards. This paper obtained the groundwater buoyancy reduction coefficients of 36 types of clays through model tests and conducted a finite element simulation to obtain the buoyancy reduction coefficients of additional clays with varying soil properties. Machine learning methods, including extreme gradient boosting (XGBoost) and random forest (RF) algorithms, were used to analyze and identify the soil parameters that have a significant impact on the reduction of groundwater buoyancy. It was found that the permeability coefficient and saturation are the primary factors that influence the reduction of groundwater buoyancy. Additionally, the prediction models developed by XGBoost and RF were compared, and their accuracy was evaluated. These research findings can serve as a reference for designing underground structures that can withstand the potential risk of buoyancy in clay. [ABSTRACT FROM AUTHOR]

Micro-Electro-Mechanical System (MEMS)-based pressure sensors operating on the principle of piezoresistivity have found profound application in various fields like automobile, aerospace, aviation, biomedical and consumer electronics. Various research studies have been conducted to optimize the design of MEMS-based pressure sensors to meet specific requirements of different fields. Modification in the structure of the piezoresistors placed on these sensors has shown great effect in this regard. However, most of these improvements have been validated through fabrication and measurement, but there has been a lack of significant studies developing analytical models to explain these improvements. This paper studies the performance of a single-turn piezoresistor design on a square silicon diaphragm. The analytical model relates the dimensions of the single-turn piezoresistor on a square diaphragm to the output voltage, and hence, sensor sensitivity is laid out. The correctness of the relation is also validated through Finite Element Analysis (FEA) performed using COMSOL Multiphysics software. Hence, an optimized single-turn design is presented which achieves a sensitivity of 203.57 mV/V/MPa over a pressure range of 0–1 MPa. These results are then compared to work from existing literature. The comparison shows an improved performance which was achieved by optimizing the design through its derived analytical model. The proposed sensor can be utilized in disposable blood pressure measurement system where high sensor sensitivity is required. [ABSTRACT FROM AUTHOR]

Stainless steel has the characteristics of oxidation resistance, high temperature resistance, corrosion resistance, high strength, and high yield ratio. The use of stainless steel bars can extend the life of a structure, reduce later maintenance costs, and reduce the whole life cycle cost of the structure. In this paper, nine concrete columns reinforced with duplex stainless steel (S2205) (DSSRC) and nine ordinary reinforced concrete columns (ORC) were poured with the diameter of steel bars as the parameter, and axial compression tests were carried out on these eighteen concrete columns. The failure mode of the concrete columns is analyzed, and the compressive performance indexes of the two kinds of concrete columns are compared. The results show that, compared with the ORC, the cracking load of DSSRC is increased by 33%, the ultimate load is increased by 30.7%, and the deformation performance of the DSSRC is also improved significantly. On the basis of the test, the finite element model of DSSRC was established with the help of ABAQUS software, and the obtained failure law was consistent with the test; the experimental value, the calculated value, and the numerical simulation value of the axial compression capacity were in good agreement, which verified the feasibility of the test and provided a theoretical basis for practical engineering applications. [ABSTRACT FROM AUTHOR]

This paper describes the use of cold and hot composite forming technology to produce pointed curtain wall profiles. An electromagnetic–temperature coupling model was constructed using ANSYS to study the temperature and electromagnetic field distribution during the forming process. Numerical simulation was used to optimize the process parameters to obtain the optimum heating parameters with a current of 4000 A, a frequency of 35 kHz, and a duration of 2 s. The accuracy of the model was also verified through experiments. The simulation results show that the use of a conductive magnet can improve the induction heating efficiency, increasing the heating frequency and the temperature peak; however, it also increases the temperature difference. Sharp-corner curtain wall profiles were successfully produced using the optimized process parameters. The temperature of the heating zone was measured using an infrared thermal imager, and the relative errors between the maximum heating temperature obtained from the simulation and the actual measured values were 5.37% and 5.02%, respectively, indicating that the finite element model performs well in terms of prediction. [ABSTRACT FROM AUTHOR]

In order to better analyze and control the micro milling process of micro ball-end milling cutter, a method combining finite element method (FEM) and regression analysis is proposed to simulate and analyze the micro cutting process of cutting edge micro-element at different axial height positions to achieve micro milling force prediction. Combining cutting edge curve equations and actual measurements establish an accurate micro ball-end milling cutter model, and discrete along the axial direction of the cutter to obtain multiple sets of cutting edge micro-element of equal thickness. In this study, a workpiece micro-element model corresponding to the axial height position of the cutting edge micro-element is established based on the actual cycloidal motion trajectory during the micro milling of the cutting edge. Finite element simulation of single-edge bevel cutting of cutting micro-elements is implemented. Based on the micro cutting force data obtained from the micro cutting simulation, regression analysis is used to obtain the cutting edge micro-element unit cutting force related to axial height and cutter rotation angle for a certain amount of feed per tooth, and then the integral summation is used to achieve the micro milling force prediction. A comparative analysis of the full slot micro milling experiments shows that the predicted micro milling forces are in good agreement with the measured values, which directly verifies the correctness and reliability of the cutting edge micro-element cutting numerical simulation and micro milling force prediction method in the paper. [ABSTRACT FROM AUTHOR]

This paper proposes an efficient hybrid analytical-computational approach for the simulation of mechanical vibrations and sound radiation in wind turbine drive trains.The computational procedure encompasses the detailed modeling of vibrational sources and structural sound paths as well as the major panels of airborne noise radiation. The angle-varying mesh stiffness is obtained from a series of quasi-static finite element simulations. A novel procedure is proposed to obtain the time-varying mesh stiffness at fluctuating speed. The varying mesh stiffness is introduced as a parametric excitation in an analytical gear model, and the Fourier-transformed results are used as vibrational sources in a finite-element-based harmonic response analysis of the drive train. The present paper focuses on the modeling of gear contact and gearbox vibrations. The models and procedures are outlined, and computational results are compared to physical measurements on a 2.5 MW wind turbine. The results are in good qualitative agreement at tonal frequencies. This is particularly the case at fluctuating speed, where both the simulation and the measurement show the characteristic effect of frequency modulation. The computational procedure has been expanded to the whole drive train and is effectively applied in the conception and evaluation of design measures for the reduction of tonal amplitudes. [ABSTRACT FROM AUTHOR]

Magnetic flux leakage (MFL) response predicting is important for defect estimation. This paper first proposes a concept of basic signal by discovering the combination property of the MFL response. The basic signal can be used to predict the MFL response conveniently by a basic signal combination method (BSCM), which is also innovatively put forward in this paper. In this method, the basic signal is calculated in advance, and the MFL response can be calculated by several transformation and combination operations. Both the simulation and experimental results demonstrate the feasibility of BSCM. Compared with other traditional methods (magnetic dipole method and finite-element method), BSCM shows a good performance on both the computational speed and accuracy. [ABSTRACT FROM AUTHOR]

Finite element method is an important method to solve mathematical problems in engineering. Many mathematical equations are difficult to solve, but it becomes very simple after using the finite element method. In this paper, the finite element method is applied to the calculation of gravity anomaly. First, the variational equation of gravity anomaly calculation is established, and then the gravity anomaly value ten times the distance away from the anomaly body is used as the boundary condition. By comparing the gravity anomaly obtained by solving the stiffness matrix with the analytical solution, it can be found that the method in this paper has high accuracy. Finally, the model of Jinchuan copper nickel deposit is used for calculation, and the calculated gravity anomaly field is inverted with Growth3D. It can be found that the inversion result is very close to the model, which verifies the effectiveness of the algorithm in this paper. [ABSTRACT FROM AUTHOR]