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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]

An epiretinal membrane (ERM) is a fibrocellular proliferation on the inner surface of the retina causing blurred and distorted central vision. Surgery is the only effective method for ERM removal. This paper investigated the mechanical properties of ERM peeling using the finite element (FE) method. A FE model of ERM formation on the retina surface was constructed. The failure criterion was applied to the attachment pegs to represent the adhesive force between the ERM and retina. The simulation results were consistent with the experimental data in published research. The maximum peeling force was 4.1 mN at a peeling velocity of 2 mm/s and an angle of 30°. The peeling force was minimum at the peeling angle of 45° and increased with the increase in peeling velocity and Young's modulus of the membrane. The outcome of this paper can improve the safety and efficiency of ERM removal. [ABSTRACT FROM AUTHOR]

Alternating current (ac) losses in conductor-on-rounded-core (CORC) cables of YBCO high-temperature superconducting (HTS) tapes are a significant challenge in HTS power applications. This study employs two finite element analysis (FEA) models to investigate the contributions from different ac loss components and provide approaches for reducing ac losses in cables. An FEA model based on the T-A formulation treats the cross section of thin superconducting layers as 1D lines and, therefore, only can predict the ac loss generated by the perpendicular magnetic field. In contrast, the model based on H-formulation can be performed on the actual 2D rectangular cross section HTS tapes to provide the total ac losses generated by magnetic fluxes penetrating from both the edges and surfaces of HTS tapes, although this model requires more computing time and memory. The 1D and 2D simulation models were validated by cross comparing the results from both models and by comparing sub-section and full cross section models. Subsequently, two models relate cable design and operational parameters to the surface and edge losses of a two-layer CORC cable by considering the (1) relative contributions of edge and surface losses to the overall ac losses; (2) effect of the current distribution between inner and outer HTS layers on ac losses; (3) impact of the tape alignment on ac losses in each HTS layer; (4) influence of the thickness of HTS layers on ac losses; (5) effect of size and number of inter-tape gaps on ac losses; and (6) contribution frequency on the ac losses. The research results given in this paper are therefore not only valuable to suggest strategies for reducing ac loss in multi-layer cables but also for developing more accurate and effective methods to calculate ac loss in CORC HTS cables. [ABSTRACT FROM AUTHOR]

The numerical simulation of paperboard creasing and folding processes is of increasing importance for the design and production of safe and reliable packaging systems. The extreme material anisotropy and the complexity of these processes require however simulation capabilities which are seldom available in commercial codes. Several approaches have been proposed in the literature over the years, in most cases making use of non-linear material models developed ad hoc for this purpose. These models, some of which are very effective and accurate, are not in general available in commercial codes and are often based on the definition of a large number of parameters. In this paper, the possibility to obtain acceptable, first-hand simulation results using only features already available in a commercial code is investigated. An advanced continuum constitutive model, recently presented in the literature, has been used as a reference for tuning the model and for assessing its accuracy. It is shown how standard features, usually available in state-of-the-art commercial codes, can be employed to deal with the extreme material anisotropy, obtaining qualitatively good results in both the creasing and folding phases. The used standard model accounts for the extremely high anisotropy by means of embedded shell elements, playing the role of reinforcements in the fibre direction. The matrix is assumed to be isotropic and elastoplastic, with properties determined based on the behaviour in the thickness direction. The adopted plasticity model is a modified Drucker-Prager model with a cutoff on the tensile pressure side, available in the used commercial code. The procedure adopted for the identification of the small number of required material parameters is also discussed. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Segmentally assembled bridges are increasingly finding engineering applications in recent years due to their unique advantages, especially as urban viaducts. Vehicle loads are one of the most important variable loads acting on bridge structures. Accordingly, the influence of overloaded vehicles on existing assembled bridge structures is an urgent concern at present. This paper establishes the finite element model of the segmentally assembled bridge based on ABAQUS software and analyzes the influence of vehicle overload on an assembled girder bridge structure. First, a finite element model corresponding to the target bridge is established based on ABAQUS software, and the load is controlled to simulate vehicle movement in each area of the traveling zone at different times. Second, the key cross-sections of segmental girder bridges are monitored in real time based on the force characteristics of continuous girder bridges, and they are compared with the simulation results. Finally, a material damage ontology model is introduced, and the structural damage caused by different overloading rates is compared and analyzed. Results show that the finite element modeling method is accurate by comparing with on-site measured data, and it is suitable for the numerical simulation of segmental girder bridges; Dynamic sensors installed at 1/4L, 1/2L, and 3/4L of the segmental girder main beams could be used to identify the dynamic response of segmental girder bridges; The bottom plate of the segmental girder bridge is mostly damaged at the position where the length of the precast beam section changes and the midspan position. With the increase in load, damage in the direction of the bridge develops faster than that in the direction of the transverse bridge. The findings of this study can guide maintenance departments in the management and maintenance of bridges and vehicles. [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 work is built on a previous research by Wiryana and Berg, in which wicking into four wet-formed paper stripes, consisting of cellulose fibers and four different percentages of the powdered carboxymethyl cellulose (CMC) superabsorbent, was studied experimentally. Because of the swelling of cellulose fibers and CMC powder on contact with water, the wicking was accompanied by a swelling of the matrix. A finite element/control volume (FE/CV)-based computer program is used for the first time to model the wicking in such swelling porous medium. The simulation used a novel form of continuity equation, which included the effects of liquid absorption and matrix swelling, in conjunction with the Darcy's law to model the single-phase flow behind a clearly defined liquid-front. A new method of estimating the time-varying permeability of the paper, based on the absorbed liquid-mass vs. time plots, is also proposed. Later, this time-dependent permeability is used in the numerical simulation to change the permeability in elements behind the moving liquid-front as a function of the time that the element has been wetted by the liquid, since the passage of the liquid-front. The numerical prediction of the wicking-front location as a function of time compares well with the reported experimental data. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2536-2544, 2012 [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 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]

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]

The bone lacunar-canalicular system (LCS) is a unique complex 3D microscopic tubular network structure within the osteon that contains interstitial fluid flow to ensure the efficient transport of signaling molecules, nutrients, and wastes to guarantee the normal physiological activities of bone tissue. The mass transfer laws in the LCS under microgravity and hypergravity are still unclear. In this paper, a multi-scale 3D osteon model was established to mimic the cortical osteon, and a finite element method was used to numerically analyze the mass transfer in the LCS under hypergravity, normal gravity and microgravity and combined with high-intensity exercise conditions. It was shown that hypergravity promoted mass transfer in the LCS to the deep lacunae, and the number of particles in lacunae increased more significantly from normal gravity to hypergravity the further away from the Haversian canal. The microgravity environment inhibited particles transport in the LCS to deep lacunae. Under normal gravity and microgravity, the number of particles in lacunae increased greatly when doing high-intensity exercise compared to stationary standing. This paper presents the first simulation of mass transfer within the LCS with different gravity fields combined with high-intensity exercise using the finite element method. The research suggested that hypergravity can greatly promote mass transfer in the LCS to deep lacunae, and microgravity strongly inhibited this mass transfer; high-intensity exercise increased the mass transfer rate in the LCS. This study provided a new strategy to combat and treat microgravity-induced osteoporosis. [ABSTRACT FROM AUTHOR]

The solution of the elastic-plastic contact is of major importance in contact mechanics because contact damage and wear are responsible for the failure of many machine elements subjected to contact load. In many situations including gears and bearings, the load is transmitted through a small contact region, i.e. a concentrated contact, and the resulting high gradients of stress often exceed the plastic yield limit of the softer material. Plastic flow is initiated at a certain depth, resulting in modification of contact geometry and of the stress state that can lead to crack inception and propagation. Understanding the contact behaviour in the presence of plastic strains is fundamental for predicting the contact resistance. Considering the mathematical model complexity for the contact between bodies of arbitrary boundary, as well as the dissipative nature of plasticity, an analytical solution for the elastic plastic contact problem is hard to accomplish. Alongside finite element analysis, semi-analytical methods are the only existing simulation tools for the elastic-plastic contact problems. This paper extends a previously reported elastic-plastic contact solver developed by the same author, by considering friction. In the previous solver iteration, residual displacements were calculated only in the normal contact direction, thus assuming that the shear displacements are small enough to be neglected, in other words, the contact was assumed frictionless. By considering friction, a slip-stick contact process is introduced, adding a new iterative loop in which the contact pressure and shear stresses are iterated until convergence is reached. The new computer simulation tool is expected to give more realistic predictions for the elastic-plastic contact between materials with dissimilar elastic properties, in which case the shear tractions disturb the stress and displacements fields calculated for the frictionless contact case. The results are expected to contribute to a better understanding of the contact processes in the presence of both plastic strains and friction. [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]

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]

This paper presents the results of computer simulations of fracture in three laboratory tests: the three-point bending of a notched beam cut from sandstone, the pull-out test of a self-undercutting anchor fixed in sandstone, and the pull-out test of a bar embedded in concrete. Five material failure criteria were used: Rankine, Coulomb–Mohr, Drucker–Prager, Ottosen–Podgórski, and Hoek–Brown. These criteria were implemented in the Abaqus® FEA system to work with the crack propagation modeling method—extended finite element method (X-FEM). All criteria yielded similar force–displacement relationships and similar crack path shapes. The improved procedure gives significantly better, close-to-real crack propagation paths than can be obtained using the standard subroutines built into the Abaqus® system. [ABSTRACT FROM AUTHOR]

In this paper, a failure analysis of the TMT90m + composite wind turbine blade performed by combining numerical simulation and full-scale destruction tests is presented. The complex failure characteristics of the skin were studied in detail and a driving relationship was obtained. From the results, it was found that the stress concentration leading to local buckling was due to the geometric and layup nonlinearities of the destruction region. This in turn contributed to the successive occurrence of matrix failure and fiber failure. Further, by using the method of finite element secondary development, the accuracy of four commonly used failure criteria for wind blade failure prediction is discussed. From the results, it was found that the Chang-Chang model has ideal prediction accuracy and is more suitable for engineering applications in blade structure design. [ABSTRACT FROM AUTHOR]

The UMo-Al monolithic fuel element has a special failure mode of blistering on the cladding surface under high temperature and high burn-up conditions. In order to provide an auxiliary means for the safety analysis and failure limit formulation of the fuel element, this study establishes a numerical simulation method of fuel failure behavior, considering the fracture behavior and the fission gas pressure acting on the cracks for the UMo-Al monolithic fuel element. Numerical simulation is based on ABAQUS software and the extended finite element method (XFEM) established by programming FORTRAN subroutines UMAT, UMATHT, and UAMP and using the thermo-mechanical sequential coupling method. Combined with Python to secondary develop ABAQUS with the FORTRAN subroutine, this study realizes the coupling of fission gas pressure load and crack propagation. This study obtained the failure threshold temperature, blistering height, area, and other blistering characteristics of the UMo-Al monolithic fuel element through numerical simulation of annealing experiments on L1P460 in RERTR-12. A comparison of the numerical simulation results with the RERTR-12 experiment shows that the method established in this study can effectively analyze blistering failures. [ABSTRACT FROM AUTHOR]

Engineers pay more and more attention to the economic benefits of foundation pit engineering. At present, the optimal design of the foundation pit supporting structure mainly focuses on strength and functional design, and there is no mature theoretical design method for deformation control. In this paper, a method for calculating the overall deformation of a foundation pit supporting structure based on the principle of minimum potential energy is proposed. Based on this method, the optimal design of the foundation pit of Guangzhou Baiyun District Comprehensive Transportation Hub Metro Station is realized. The deformation calculation results and optimization design scheme are validated by finite element numerical simulation and field monitoring data. The results show that the proposed theoretical algorithm predicts the pile deformation curves better than the finite element method, suggesting the proposed theoretical method is reasonable and the optimization scheme of the retaining pile is feasible. In the optimized design, the deformation of the foundation pit retaining pile is controlled by its push-back effect. The proposed deformation calculation method can realize the overall deformation calculation of the foundation pit supporting structure. [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]

Purpose: The purpose of this paper is to compare the single-sided packaging structure and double-sided packaging structure of high-power module and study the overall heat dissipation performance and reliability of the module. Design/methodology/approach: In this paper, the single-sided packaging structure and double-sided packaging structure of power module are designed based on Wolfspeed products. This paper is analyzed by finite element method. First, the heat dissipation performance of single-sided packaging structure and double-sided packaging structure is analyzed; second, the deformation and stress of single-sided packaging structure and double-sided packaging structure are compared and analyzed; and finally, the cumulative plastic deformation of single-sided packaging and double-sided packaging structures are compared and analyzed, and the fatigue life of the structure is calculated based on the plastic deformation. Findings: In the heat transfer simulation, under the same power input, the heat dissipation performance of single-sided packaging structure is not as good as that of double-sided packaging structure. Under the reliability simulation of the same temperature cycle standard, the maximum equivalent stress of single-sided packaging structure is lower than that of double-sided packaging structure, but the fatigue life prediction based on plastic strain shows that the fatigue life of double-sided packaging structure is not different from that of single-sided packaging structure. Originality/value: This paper creatively simulates the thermal characteristics and reliability of single-sided packaging structure and double-sided packaging structure and proves the advantages of double-sided packaging structure compared with single-sided packaging structure from the aspects of heat transfer performance and reliability. [ABSTRACT FROM AUTHOR]

This paper discusses modelling and numerical issues in the simulation of the Landau-de Gennes (LdG) model of nematic liquid crystals (LCs) with cholesteric effects. We propose a fully implicit, (weighted) L2 gradient flow for computing energy minimizers of the LdG model, and note a time-step restriction for the flow to be energy decreasing. Furthermore, we give a mesh size restriction, for finite-element discretizations, that is critical to avoid spurious numerical artifacts in discrete minimizers, particularly when simulating cholesteric LCs that exhibit 'twist.' Furthermore, we perform a computational exploration of the model and present several numerical simulations in three dimensions, on both slab geometries and spherical shells, with our finite-element method. The simulations are consistent with experiments, illustrate the richness of the cholesteric model, and demonstrate the importance of the mesh size restriction. [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]

This paper demonstrates the importance of a proper contact algorithm selection when a constitutive model is correlated and validated, especially in the case of brittle materials. A parametric study is carried out to study the influence of contact parameters on the outcomes of the numerical simulations of a dynamic compression test. The split Hopkinson pressure bar (SHPB) model is developed, and sandstone rock is considered as a representative material having considerably different properties compared to SHPB bars. The finite element method (FEM) and smoothed particle hydrodynamics (SPH) were used to simulate specimen behaviour using a LS-Dyna solver. Two contact types based on the penalty method are analysed: nodes to surface (FEM and SPH) and surface to surface (FEM only). Furthermore, three approaches of contact stiffness calculation are used for each contact type. The waveform data and failure patterns are then compared among all simulated cases and the corresponding experimental outcomes. It is found that the soft constraint stiffness (SOFT = 1) provides the best outcomes, especially in the case of one-way contact, and is nearly insensitive to stiffness scaling parameters. By contrast, standard (SOFT = 0) and segment-based (SOFT =2) approaches require a substantial effort in adjusting the stiffness scaling parameters to obtain satisfactory results. This paper provides valuable guidance for correlating and validating parameters of constitutive models for rock and other brittle materials in the SHPB test. [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]

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]

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]

This work is focused on the application of a modelling system to simulate 3-D interaction between the Curonian Lagoon and the Baltic Sea coastal waters and to reflect spatio-temporal dynamics of marine waters in the Curonian Lagoon. The model system is based on the finite element program package SHYFEM which can be used to resolve the hydrodynamic equations in lagoons, coastal seas, estuaries and lakes. The results of a one year 3-D model simulation with real weather and hydrological forcing show that the saline water intrusions from the sea through Klaip ?eda Strait are gradually decreasing with distance from the sea and become negligible (average annual salinity about 0.5‰) at a distance of about 20 km to the south of Kiaule?s Nugara island. Analyses of the simulation results also show this area being highly heterogeneous according to the vertical salinity distribution. While in the deeper Klaip ?eda Strait (harbour waterway) differences in average salinity between near bottom and surface layers varies in the range 2-2.5 ‰, in the rest of the Curonian Lagoon it is less than 0.1 ‰. Analyses of the simulation results confirmed the presence of a two-directional flow that from time to time changes to either saline water one-directional flow to the Curonian Lagoon or fresh water one-directional flow to the sea. Two-directional flow duration decreases with a distance from sea entrance in Klaip ?eda Strait from around 180 days yr-1 close to the sea entrance to 50 days yr-1 just behind Kiaul ?es Nugara island. One-directional outflow duration is increasing with a distance from the sea entrance from 100 to 225 days yr-1. One-directional inflow duration occurs in the range 85-100 days yr-1. The analysis of the ratio of buoyancy layer thickness to water depth (hb/H) and the Wedderburn number showed three main flow regimes in the strait, identifying the main importance of wind action in the along-strait direction. Absence of wind or cross-strait wind regimes allow the maintenance of a two-layer flow typical of estuarine dynamics. [ABSTRACT FROM AUTHOR]

The annual drift of ÎĽ Gal level is an important indicator of superconducting gravimeters, which helps geophysicists to clarify the weak geophysical signals. In this paper, a finite element simulation model of the superconducting gravimeter sensor is developed based on the H formulation for evaluating the contribution of the excitation AC losses and the AC losses under operating conditions to the superconducting gravimeter’s drift. The model combines the H formulation and the heat transfer module of COMSOL Multiphysics software to calculate the AC losses of the superconducting gravimeter’s test mass and obtain the distribution images of the test mass’s temperature due to the AC losses-induced heating. The overall temperature rise of the test mass is obtained by assuming that it heats up uniformly and thus combines the temperature dependence factor (10 ÎĽ Gal mKâˆ'1) of the superconducting gravimeter to derive the instrument drift induced by AC losses. Then, the long-term drift due to excitation losses can reach 0.847 ÎĽ Gal yrâˆ'1, while the operating losses can be 0.45 ÎĽ Gal yrâˆ'1 or even less, according to the simulation. In addition, this paper discusses the effects of the parameters (index number, critical electric field, and critical current density) in the Eâ€"J power law introduced by the H formulation on the AC loss evaluation. It is concluded that the AC losses are sensitive to the critical current density, and increasing the test mass’s critical current density helps enhance the stability of the superconducting gravimeter. [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]

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]