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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]

Nonlocal problems involving fourth-order terms pose several difficulties such as numerical discretization and its related convergences analysis. In this paper, the well-posedness of the extended Fisher-Kolmogorov equation with nonlocal diffusion is first analyzed using the Faedo-Galerkin technique and the classical compactness arguments. Moreover, we adopt a BDF2 scheme for time discretization and a mixed Galerkin scheme for spatial discretization. Then, we derive the optimal order convergence rates of the fully discrete system. Finally, some numerical simulations and convergence results are provided to confirm the theoretical results and the accuracy of the proposed scheme. [ABSTRACT FROM AUTHOR]

Understanding the formation of impact craters on planetary surfaces has fundamental importance in geology, impact dynamics, and planetary sciences. The finite element-smoothed particle hydrodynamics (FE-SPH) adaptive method combines the advantages of smoothed particle hydrodynamics (SPH) and finite element method (FEM) in solving hypervelocity impact (HVI) problems. Employing FE-SPH adaptive method is a new idea for the analysis of planetary impact cratering which is different from impact-simplified arbitrary Lagrangian Eulerian (iSALE). In this paper, we establish a complete numerical model of planetary impact cratering through the FE-SPH method, including material failure criterion, thermodynamic analysis, gravity preloading, etc. We reproduce the numerical results by Collins et al. (2012) and highly consistent results are obtained through comparative analysis. This study simulates the formation process of simple and complex impact craters, and the temperature, pressure, density, and geometric shape of the impact zone can be quantitatively obtained. We further analyze the distribution of polymorphs and rock fragmentations in the impact zone based on the theories of shock metamorphism. The proposed analysis method may assist geologists in conducting geological studies. • We establish a complete numerical model of planetary impact cratering different from iSALE. • We analyze the distribution of high-pressure polymorphs based on shock metamorphism. • The FE-SPH model has higher numerical precision for planetary cratering impacts. [ABSTRACT FROM AUTHOR]

• The effectiveness of thin-walled cellular beams manufactured by RFSSW was developed. • A parameterized finite element model (FEM) of the cellular beam was developed. • Results of numerical simulations and experimental tests were compared. • A parametric FEM model of the cellular beam was developed in the ADINA system. • The numerical model was used to analyze beams with different cross-sections. The paper presents analyses of thin-walled I-beams constructed from 6061-T6 aluminum alloy using refill friction stir spot welding (RFSSW). A parametrized finite element model of the reference cellular beam was developed, and the results from numerical simulations and experiments were compared. Subsequently, the validated numerical model was utilized to conduct an in-depth analysis of three additional beams featuring distinct cross-sections. To assess the weld behavior, experiments were conducted on samples composed of two sheets connected by two spot welds. The outcomes of these investigations underscore the suitability of RFSSW as a method for constructing thin-walled structures in civil engineering applications. [ABSTRACT FROM AUTHOR]

In this paper, a novel numerical simulation approach based on the finite element method for dynamically modeling the excavation process of shield tunneling is proposed, with the shield-ground interactions well captured. This method is capable of mimicking the alternating modes of advancing and stopping of a shield boring machine during underground construction, with the important effects of the cutterhead rotation and slurry support pressure considered. Under the cutting action, the soil at the excavation face would experience irreversible deformation and damage, such that additional support needs to be provided by the cutterhead blades and slurry to maintain stability. The impacts of key construction parameters are examined, including cutterhead rotary speed, advance rate, and slurry support pressure, on shield tunneling operations and ground responses. The numerical model is rigorously validated against physical model experiments. This work provides useful insights into the mechanistic processes in the stratum during shield tunneling, including the spatiotemporal evolution of ground deformation patterns and stress redistributions. The results offer valuable guidance for optimizing shield tunneling operations and enhancing tunneling safety and efficiency. [ABSTRACT FROM AUTHOR]

• The flexural buckling behaviour of austenitic stainless steel semi-oval hollow section columns was studied. • Twelve pin-ended column tests were conducted. • FE models were developed to validate against the test results and then adopted to conduct parametric studies. • The codified buckling curves were evaluated and led to an overall good level of design accuracy. Semi-oval hollow section is an innovative cross-section profile and consists of one semi-circular flange, one flat flange and two flat webs. While the semi-circular flange (exposed to fluid or wind) offers a low level of hydrodynamic or aerodynamic drag, the flat elements facilitate connections with other members. The flexural buckling behaviour and resistances of austenitic stainless steel semi-oval hollow section columns are investigated in this paper. An experimental programme was firstly conducted on two austenitic stainless steel semi-oval hollow sections, with six column specimens of varying member lengths adopted for each cross-section, and included tensile coupon tests, initial geometric imperfection measurements and pin-ended column tests. Both 'C'-shaped flexural buckling (with failure specimens bowing towards semi-circular flanges) and 'reverse C'-shaped flexural buckling (with failure specimens bowing towards flat flanges) were observed upon testing. The experimental programme was accompanied by a numerical modelling programme, with finite element models developed to simulate the test results and then adopted to conduct parametric studies to generate further numerical data. On the basis of the test and numerical data, the relevant buckling curves for austenitic stainless steel circular hollow section columns, as provided in the European code, American specification and Australian/New Zealand standard, were evaluated for their applicability to austenitic stainless steel semi-oval hollow section columns. The evaluation results generally revealed that the codified buckling curves led to overall accurate and consistent flexural buckling resistance predictions when used for austenitic stainless steel semi-oval hollow section columns. [ABSTRACT FROM AUTHOR]

The bidomain equations form the state-of-the-art model of cardiac electrophysiology and describe normal or pathological propagation of the excitation wave through cardiac tissue. If based on mechanistic cell models and applied to anatomically realistic geometries, their discretization requires very fine resolutions both in space and time and renders the numerical solution an extremely challenging computational problem. In this paper, we address this challenge by combining space-time adaptive discretization with dynamic load balancing for parallel computing. We use multilevel finite element methods for the spatial adaptation of the mesh, embedded Rosenbrock time integration for an adaptive choice of step sizes, and non-overlapping domain decomposition for the parallelization. In order to further reduce the computational costs, we exploit the sparsity of local matrices during the assembly of global FEM matrices which ensure an optimal usage of memory. In numerical tests, we demonstrate the feasibility of our approach that a substantial reduction factor of computing time is achieved w.r.t the static grid computation and a good parallel efficiency is achieved. [ABSTRACT FROM AUTHOR]

Simulation of the failure process of non-intact rock containing initial cracks, voids, and other discontinuities is a research hotspot in rock mechanics and geotechnical engineering. The damage smear method has attracted wide attention due to its ability to realistically depict the complete failure processes of rock from the microscopic to the macroscopic scale. However, when portraying pre-existed discontinuities, the damage smear method suffers from major difficulties such as mesh dependency and stress singularity. To overcome the limitations of current methodology, this paper proposes a novel non-break modeling strategy inspired by the extended finite element method for dealing with embedded discontinuities, in which the discontinuity of the physical fields across crack faces or the void boundary, as well as the stress singularity at the crack tip, can be characterized by introducing appropriate enrichment functions, and the penalty method is used to impose frictional contact constraints. Applications of the combined method of the improved modeling strategy and damage smear analysis to laboratory-scale and engineering-scale numerical examples show a satisfactory approximation with the analytical solution or experimental observations, indicating that the current modeling strategy can further improve computational accuracy while retaining the advantages of the damage smear method. [ABSTRACT FROM AUTHOR]

• A modified GTN model considering the effects of anisotropy and shearing on micropore evolution is introduced. • The constitutive model is compiled into a VUMAT subroutine for numerical simulation to accurately predict the plastic deformation of aluminum alloy sheet. • The parameters in constitutive model are calibrated by inverse FE method and the validity of the modified GTN model is verified through the uniaxial tensile experiment. • A FE model of the mould-sheet coupling system is further developed to improve the forming performance. Traditional GTN meso-damage model, neglecting the effect of anisotropy or shearing on the evolution of microvoid, leads to the lower predictive capabilities of forming defects for aluminum alloy sheets. In this paper, a modified constitutive model of aluminum alloy sheet considering the effect of both anisotropy and shearing is proposed, and the corresponding model parameters are calibrated by inverse finite element method and uniaxial tensile test of the smooth strip sheet without hole. Then, the constitutive equation of the modified model is compiled into a VUMAT subroutine using backward Euler integration algorithm and FORTRAN language to perform subsequent numerical simulation in ABAQUS/Explicit, the validity of the proposed shear-corrected GTN model is also verified through the uniaxial tensile experiment of the strip sheet with a hole in the middle. Finally, finite element (FE) model of the mould-sheet coupling system is developed based on the modified GTN model, and the influence of punching speed, blank holder force, friction coefficient and dwell time on the forming performance of AA5052 aluminum alloy sheet is investigated. The results show that ductile fracture of aluminum alloy sheet is most prone to exist on the upper fillet of part. [ABSTRACT FROM AUTHOR]

• Proper quantification of joint rotational stiffness (JRS) of a flight intersection joint (FIJ) influences the dynamic characteristics of a flight vehicle. • JRS of an FIJ is often determined experimentally due to the lack of a right predictive model. • An analytical model is proposed to evaluate the JRS of a radial-type FIJ when subjected to an external bending moment. • Numerical analyses and experiments are performed on six different FIJ configurations. • JRS and moment-rotation behavior predicted by the proposed model are correlated with both experimental and numerical analyses. • Further, the effect of joint clearances on the behavior of FIJ is investigated through the present model. Joint rotational stiffness (JRS) of a flight intersection joint (FIJ) and its accurate quantification play an essential role in studying the dynamic modal characteristics of a flight vehicle. This JRS of a FIJ is mostly determined through elaborate experiments due to the non-availability of a reliable predictive model. Therefore, in this paper, an analytical model is proposed to evaluate JRS of a radial type FIJ when subjected to external bending moment. In this model, at first, the tensile and compressive part of the FIJ section is identified by determining the neutral axis position. The respective part's contributing stiffness is then estimated by employing a spring-mass model. Later, the JRS expression is derived from the moment equilibrium condition and expressed as a function of the stiffness of the tensile and compressive part and neutral axis position. Subsequently, finite element analysis (FEA) is conducted with different numbers of screws, followed by detailed experimental investigations. The proposed analytical model is validated with the results from FEA and experiments for different screw configurations of FIJ. Further, the proposed model is extended to account for the effect of joint clearances on the JRS and the corresponding moment-rotation characteristics of the FIJ. [Display omitted] [ABSTRACT FROM AUTHOR]

The particle sedimentation and phase change in the mushy zone are accompanied by a variety of complex transfer processes involving momentum, heat, and mass. It is very important to investigate the coupling process of particle settling and melting in the mushy zone for revealing the mechanism of the solid-liquid phase change. In this paper, the motion process and heat transfer characteristics of an elliptic particle as well as two particle interactions in the vertical channel were solved by the finite element method with the consideration of coupling of the phase change and motion. The Arbitrary Lagrangian-Euler Method (ALE) was employed to track the interface of the moving particle and fluid. Results show that the elliptical particle settles along the channel's center line vertically under gravity and undergoes phase change simultaneously. Uneven velocity and temperature fields surrounding the particle are generated by sedimentation, resulting in the particle with an irregular shape. When the initial position of the particle deviates from the center line, the particle deflects during the sedimentation and shifts both left and right in the X -direction. The different initial angles of settling also affect the sedimentation velocity and melting rate. When two particles settle simultaneously, they will lead to complex movement and heat transfer due to the interaction between each other. If the arrangement is eccentric, both particles undergo complex deflections during sedimentation, leading to different melting rates for the two particles. [ABSTRACT FROM AUTHOR]

The working environment of industrial fields where the Particulate Reinforced Composites (PRCs) are commonly used is complex. In these harsh environments, PRCs produce some nonlinear strains, such as plastic, thermal, and creep strains, which affect the performance of PRCs to some extent. In addition, the actual structure of PRCs contains a massive amount of inclusions, and the number of inclusions could reach the magnitude of millions or even tens of millions. For the large-scale numerical simulation of PRCs, ordinary displacement finite element requires a large number of meshes, which increases their computational complexity and unsolvability. For real PRCs with random particle distribution, homogenisation theory does not accurately capture the true state of stress concentration in PRCs. The Voronoi cell finite element method (VCFEM) can be a good solution to the drawbacks of the above two numerical simulation methods. The subject of the present work explores a modified complementary energy generalized function that takes the constitutive relationship of nonlinear strain into account, proposing a two-dimensional VCFEM, formulated with plastic, thermal, and creep strain. The simulation results are compared with the computed results of a commercial finite element software Marc to verify the validity and accuracy of the VCFEM. Results of the comparison show that the VCFEM has the advantages of simple meshing and faster computation under the same precision. The VCFEM, considering plastic, thermal, and creep strains proposed in this paper, lays the foundation for future large-scale numerical simulations of PRCs containing a large quantity of inclusion structures and can realistically capture the stress concentration state of PRCs. At the end of the article, the impact of the order of stress function on the calculation results is discussed. [ABSTRACT FROM AUTHOR]

Surface ruptures resulting from seismic faulting have the potential to inflict substantial damage to bridges straddling fault lines; hence, it is imperative to investigate the impact of ground motions documented on either side of fault rupture planes—termed as across-fault ground motion—on the seismic resilience of bridges. In this paper, the object of study is a three-span, simply supported beam bridge traversing a strike-slip fault. Utilizing the LS-DYNA finite element software platform, a sophisticated three-dimensional finite element model of the selected bridge is constructed, meticulously accounting for material damage nonlinearity and structural collision contact nonlinearity. A synthetic across-fault ground motion serves as the excitation for the seismic analysis of the bridge, systematically examining the influence of the fault-crossing angle (FCA), fault sliding rise time, and ground surface permanent rupture displacement on the dynamic response and seismic damage incurred by the simply supported beam bridge. The findings demonstrate that a diminutive fault-crossing angle (FCA) corresponds to an elevated risk of longitudinal beam collapse when a simply supported beam bridge does not intersect a fault vertically. The impact of the fault sliding rise time on the magnitude of seismic response and damage sustained by the simply supported beam bridge is relatively minuscule and can be neglected. Conversely, the ground surface permanent rupture displacement profoundly influences the dynamic response and seismic damage of the bridge. The emergence of fling-step pulses from the development of ground surface permanent rupture displacement amidst seismic activity induces a shift in failure mode-from the designer-intended bending failure to an unforeseen shear failure. • A FE model of a simply-supported beam bridge is established with consideration of material and contact nonlinearity. • The systematic parameter analysis of the simply-supported beam bridge is conducted. • The failure mode and damage process of the simply-supported beam bridge are revealed. • Recommendations for the seismic design of simply-supported beam bridges subjected to strike-slip faulting are drawn. [ABSTRACT FROM AUTHOR]

• This paper reports on calculation of dislocation density in 200 mm SiC crystal grown by PVT method. • Numerical study based on a model was carried out for modeling of dislocation density. • Evolution of crystal growth interfaces were captured using a dynamic mesh technique. Physical vapor transport (PVT) is the dominant method for growing 200 mm SiC crystals, and the crystals produced by this method still have dislocations, which affect the performance of the device. In this study, the finite element analysis of 200 mm SiC crystal growth has been conducted to investigate the influencing parameters on the dislocation density. The calculations are based on the model of multiple resistance heating. The transient heat transfer for the crystal growth is first calculated. A dynamic mesh technique is then employed to consider the shape evolution of the crystal during the growth. Finally, the distributions of the internal stress and dislocation density have been calculated based on the Alexander-Haasen model. The comparison among different parameters provides guidance for reducing the thermal stress and dislocation density in the 200 mm SiC crystal growth. [ABSTRACT FROM AUTHOR]

In this paper, we compare the failure behaviors of CFRP single and double (S–D) lap joints and analyze the effects of hygrothermal aging on these joints through a comprehensive experiment and simulation. Firstly, we analyze and compare the degradation pattern of the residual strength of S–D​ lap joints under three hygrothermal environments, and reveal the aging mechanism in conjunction with the macro/fine-view failure surfaces of the joints. Secondly, we elucidate the probability distribution of joint aging failure using the two-parameter Weibull distribution. Finally, we develop a finite element model to simulate the failure process of the cohesive behavior, and compare not only the bending moment and contact stress distribution of the two joints, but also analyze the damage condition of the CFRP matrix/fiber. We define environmental degradation factors to express the failure behavior of lap joints after aging. Through the above analysis methods, we find that hygrothermal aging can seriously damage the CFRP and adhesive properties. The mechanical performance of DLJs is significantly superior to that of SLJs, and they also exhibit better reliability. Therefore, DLJs can be substituted for SLJs in some application scenarios. Additionally, our paper provides new insights into the selection of an appropriate lap bonding method. • This paper evaluates the aging durability of single and double lap joints from multiple perspectives. • The failure behavior of single and double lap joints is comprehensively compared by numerical simulations. • This paper provides some new insights into the selection of an appropriate lap bonding method. [ABSTRACT FROM AUTHOR]

In order to meet the requirements of outfitting layout and light weight, circular or elliptical holes need to be opened on the web of the hull beam. Excessive opening will lead to stress concentration and reduce the bearing capacity of the beam. For the super-standard openings, the general strengthening method cannot guarantee the ultimate bearing capacity of the beam, and locally increasing the web to form a variable cross-section beam can compensate for the lost bearing capacity. In the present paper, the three-point bending load tests of variable cross-section opening beams and equal cross-section beams are carried out. Combined with the results of nonlinear finite element analysis, the ultimate bearing capacity and failure mode of transverse bending are compared, and it is verified that the ultimate bearing capacity of beams with variable cross-section openings is better than that of beams with equal cross-section. By changing the cross-section size and optimizing the transition form, the variable cross-section perforated beam is further improved and optimized to enhance the ultimate strength. • The three-point bending load tests of variable cross-section opening beams are carried out. • Considering the actual welding deformation, the ultimate strength prediction method of perforated beam is improved. • The variable cross-section perforated beam is optimized to enhance the ultimate strength. [ABSTRACT FROM AUTHOR]

With severe corrosion issues afflicting nearly half of all high sulfur gas fields, bimetal composite tubes have emerged as an optimal solution due to their superior corrosion resistance, mechanical properties, and cost-effectiveness. These tubes have gained widespread adoption in gas gathering applications. However, the evaluation of the corrosion performance of Incoloy 825 bimetal composite tubes within high sulfur gas field environments is yet to be adequately addressed. An investigation into the welding performance of both the base metal and weld is instrumental in ascertaining the safety and reliability of bimetal composite pipes. To this end, this paper presents a thermodynamically coupled finite element model of bimetal composite pipes, developed using SYSWELD software, and corroborates the model using the borehole method for empirical verification. The study further delineates the distribution of residual stress encountered during multi-layer and multi-pass welding of bimetal composite pipes. • Welding simulation of bimetal tubes validates residual stress distribution. • Compressive stress dominates base metal; cap-shaped tensile stress is on the weld side. • High-stress near fusion line and transition layer risks cracking in bimetal pipes. • Numerical modeling and verification lead to safe application of bimetal composite pipes. [ABSTRACT FROM AUTHOR]

This paper provides an experimental and numerical investigation into the compressive behavior of built-up H-section columns fabricated using H-SA700 steel. First of all, axial compression tests were performed on nine built-up specimens. Secondly, the 3D solid finite element (FE) models were constructed using ABAQUS, and their accuracy was verified by the experimental results. And then, the effects of slenderness ratio, web height-to-thickness ratio, flange width-to-thickness ratio, channel thickness, transverse bolt pitch, bolt diameter, and longitudinal bolt pitch on the compressive strength and buckling deformation of built-up members were analyzed. Finally, the applicability of the column curves from GB 50017–2017, EN 1993-1-1, and ANSI/AISC 360–16 for H-SA700 built-up columns were assessed, and the design curves were modified. The results indicated that slenderness ratio and channel thickness were the main parameters affecting the bearing capacity of built-up members. The design curves of current codes all underestimated the compressive strength of built-up columns around the weak axis under axial loading. In addition, modified column curves could provide a conservative design for built-up H-section columns. • Nine built-up H-section columns were tested under axial loading. • Finite element models applicable for built-up H-section columns were established. • The effects of six key parameters on the compressive behavior of built-up columns were analyzed. • The applicability of the design curves of the current code for H-SA700 built-up H-section columns was assessed, and the design curves were modified. [ABSTRACT FROM AUTHOR]

Ice sphere impacts are an important issue in the study of composite materials, polar engineering, and aerospace engineering. The traditional mechanics numerical methods, rooted in classical continuum mechanics, like the Finite Element Method (FEM), grapples with the challenge of spatial derivatives not existing at the crack tip or crack surfaces, rendering it unsuitable for addressing discontinuity-related problems such as fracture and failure. Developed particle method peridynamics shows great ability in handling such discontinuous problems. This paper establishes an ice sphere impact model using the peridynamics method. To verify the accuracy of our model, we compared the simulated results with the tested results of the high-speed impacting ice sphere and obtained that the predicted impact load and crack propagation of ice spheres are consistent well with the experiment results. An isolated damage zone was found to appear at the top region when the surface crack just extends across the hemispherical plane. This phenomenon happens due to that the impact wave propagating along the sphere center axis reaches the top end faster than the surface wave, making spalling damage occurred at the top region, and the encounter between the reflected wave and the surface wave would make the spalling damage more severe. • An ice impacting model was established based on the developed particle method (Ordinary State-Based Peridynamics). • An experimental setup of an ice sphere impacting was established, and the numerical models were verified. • A more in-depth study towards the damage behavior and the impacting wave propagating on the surface was conducted. [ABSTRACT FROM AUTHOR]

• Thin-walled lenticular composite booms with different design parameters were prepared, and free-end loading experiments and coiling experiments are conducted on the established experimental platforms. • The finite element model of thin-walled lenticular composite booms are established and simulations are conducted to analyze the mechanical response during free-end loading and coiling process. • The influences of ply numbers, ply angles, fiber types and fiber contents on the performance of TLCBs were analyzed through experiments and finite element simulations. As a kind of lightweight composite structure, thin-walled lenticular booms made of fiber reinforced composite are widely used in the aerospace field because of its high stiffness in the unfolded state. In this paper, the load-bearing and coiling characteristics of the thin-walled lenticular composite booms were studied, and the effects of different design parameters and material properties were compared. Thin-walled lenticular composite booms with different ply numbers, ply angles, fiber types and fiber contents were prepared. Free-end loading experiments and coiling experiments were conducted to obtain the load-displacement curves, coiling torques and binding forces. The finite element model was established and the simulation results were compared with those of experiments. It is shown that increasing the ply number, increasing the fiber content and using fibers with lower elastic modulus can significantly enhance the load-bearing capacity of thin-walled lenticular composite booms, meanwhile reducing its coiling capacity. The booms with orthometric ply angle have greater load-bearing capacity, but the ply angle has less effect than the ply numbers, fiber types and fiber contents. The results provide feasibility for the design of thin-walled lenticular composite booms suitable for the aerospace field. [ABSTRACT FROM AUTHOR]

This paper proposes a micromechanical model based on the finite element method (FEM) to analyze the ratchetting deformation of short glass fiber-reinforced polymer composites (SFRPCs). To reasonably consider the complex mechanical characteristics of the polymeric matrix under asymmetrical stress-controlled cyclic loading, a damage-coupled nonlinear viscoelastic-viscoplastic (VE-VP) cyclic constitutive model was constructed. The cyclic constitutive model of the matrix was introduced into the FEM model utilizing a user-defined material, and the corresponding experimental validation of the matrix was conducted. Subsequently, the cyclic constitutive model was introduced into the analysis of the micro-FEM model of the composites. The random orientation was considered to generate fibers in the FEM. Based on the analysis of the microscale representative volume element (RVE) model, the effects of different fiber content and cyclic peak stress on the ratchetting of SFRPCs were studied in detail. After validation, the effects of the fiber length and fiber stiffness on the ratchetting deformation of SFRPCs are discussed based on the developed micro-FEM model. The results show that the increase in the fiber length and fiber stiffness reduced the ratchetting deformation of SFRPCs within a specific content range. The model can assess the ratchetting deformation and damage evolution within the composites to provide more accurate predictions of the ratchetting deformation of SFRPCs and guide the expanded application of SFRPCs in structures. [Display omitted] • A damage-coupled nonlinear viscoelastic-viscoplastic cyclic constitutive model of the polymer matrix was proposed. • The constitutive model was introduced into microscale finite element model through the user-defined material subroutine. • Ratchetting deformation of SFRPCs was analyzed based on the constructed microscale representative volume element model. • Effects of fiber length and fiber stiffness on ratchetting deformation and damage of SFRPCs were investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fick pore diffusion model was applied to predict the adsorption breakthrough curves. • Behaviors of counter ion was considered in ion exchange adsorption process. • Evolution of mass flux along axial direction of adsorption column were studied. • Convection flux was almost 107–108 times larger than that of pore diffusion. • Adsorbent has a good repeatability in the adsorption/elution cycles experiments. In this work, the adsorption rate of geniposidic acid (GSA) on a fixed-bed column packed with porous adsorbents was studied, thoroughly by a Fick pore diffusion model based on numerical simulation and 3D visualization. Adsorption breakthrough curves of GSA were studied experimentally, under various operation conditions such as feeding concentrations, flow rates and packed column aspect ratio. For ion exchange adsorption of GSA onto the adsorbent used in this paper, a maximum adsorption capacity reached 637.5 mmol·L−1 at 298.5 K. Modeling method for an adsorption packed column was based on the coupling of mass transfer equations with a steady velocity field obtained from Navier-Stokes equation. A finite element method was adopted by COMSOL Multiphysics with proper mesh refinement, to solve the equation system. Moreover, the influences of operation conditions on the magnitude and direction of mass fluxes induced by convection and diffusion were analyzed in details. 3D data of Mass fluxes proved that the existence of forming period and transferring period of mass transfer zone (MTZ), which are important knowledge for comprehending the dynamics of adsorption process. The magnitude of convection flux was almost 107–108 times larger than that of pore diffusion flux. Average pore diffusion diffusivities of GSA and Cl− were fitted to be 5.19 × 10−10 and 1.71 × 10−9 m2·s−1, while their maximal mass fluxes were 9.366 × 10−3 and 3.926 × 10−3 mol m−2·s−1 in simulations, respectively. Finally, adsorption and elution recycle experiments proved the feasibility of the novel GSA adsorption technology in the future scaling-up process. [ABSTRACT FROM AUTHOR]

In Part I of this paper, quasi-static fracture toughness tests were reported which were carried out on two carbon fiber reinforced polymer materials. One laminate was unidirectional and the second was composed of plies fabricated from a twill fabric. In Part II, which is presented here, micro-computerized tomography was performed providing a relationship between the observed experimental behavior and the micromechanical structure of the materials. This was carried out for the double cantilever beam (DCB), mixed mode bending (MMB) and end-notched flexure (ENF) specimens. Load–displacement curves were simulated numerically by means of a cohesive zone model and the finite element method to obtain better insight into the failure mechanisms observed for DCB and ENF specimens. [Display omitted] • Quasi-static fracture toughness testing was reported on in Part I of this paper. • Micro-computerized tomography was carried out on many of the specimens. • Damage mechanisms on the micro-scale were assessed. • Numerical simulations were carried out by means of a cohesive zone model. [ABSTRACT FROM AUTHOR]

• A numerical simulation method for the multifactor coupling of stress field and temperature field is developed. • The numerical simulation method is in good agreement with the experiment results at elevated temperatures. • The numerical simulative description of the grout material failure and fracture of a steel bar. • Prediction of the yield point and the ultimate point of FGSC from 25 °C to 1000 °C. Fire is one of the main objects of study at the cutting edge of the research on disaster prevention and mitigation in structures. In the event of a fire, the mechanical properties of the structural material will be significantly reduced, resulting in serious consequences. This paper simulates the tensile properties of sleeve grouting members at five different temperatures, to contribute to the research here. The simulated member stress-strain curves fit well with the corresponding experimental results. The paper introduces constitutive models of concrete, steel, and sleeve. Beyond that, a feasible finite element model of the grouted sleeve is proposed. Two special points' (yield point, ultimate point) coordinate formulas which are related to different temperatures (25–1000 °C) are presented. It indicates the regularity of fully-grouted sleeve tensile force-displacement curves in various temperatures. Meanwhile, the research content provides the basis for further research on reinforcing bars spliced by grout-filled coupling sleeves. [ABSTRACT FROM AUTHOR]

• The lattice structure construction method based on finite element mesh is proposed. • The optimization design method of heterogeneous lattice structure for additive manufacturing based on MIST method is proposed. • The lattice structure construction and optimization problem realized by using parametric language APDL. With the improvement of lightweight demand and the development of additive manufacturing technology, the manufacturing of complex lattice structure is made possible, and the construction of complex lattice structure is became more and more important. However, the existing commercial software will have the phenomenon of boundary cell damaged when realizing lattice structure for curve and surface graphics. Being aimed at the problem of boundary unit cell damage in the construction of large-scale lattice structure, this paper proposes a lattice structure construction method based on finite element mesh. Through the description of the parameterization, implementation principle and specific process of lattice structure, and finally compared with the existing commercial software inspire, the result is shown that this method is better than the lattice structure construction problem of commercial software, It also is solved the problem of boundary cell damage in the construction of large-scale lattice structure. In addition, many studies show that the optimized heterogeneous lattice structure is had better mechanical performance. In this paper, a method for optimizing the cross-sectional area of lattice members is proposed based on the mist method. In two-dimensional and three-dimensional numerical examples, the total volume strain energy of the lattice structure has been improved by more than 60% in theory. [ABSTRACT FROM AUTHOR]

• A finite element model was built for simulating the leaf wrapping around the roller. • The deviation value was used as the indicator of wrapping degree in the simulation. • The leaf wrapping around the rotating roller composed of four stages. • The wrapping characteristics was analyzed based on finite element method and orthogonal method. In order to solve the problem of wrapping between sugarcane leaves and rotating roller of returning the machine, the length of rotating rollers (A), the number of bulges (B), and the leaf quantity (C) were taken as influence factors in this paper. A finite element model was built to simulate the process of the leaf wrapping around the rotating roller. Through the simulation analysis of the deviation value and the wrapping time, the results showed that: (1) these factors all had an influence on the wrapping degree by comparing the average deviation value; (2) there were four stages in the wrapping process; (3) the longer the roller length, the more the number of bulges, and the less the leaf quantity, causing the less the wrapping time. In addition, a test system was designed and constructed, and the model was validated using single-factor tests compared with simulation results. The results of the experiment using the orthogonal test method, range method, variance method, and comprehensive balance method showed that: (1) the priority order of these factors was B > C > A; (2) the effects of these factors were all significant; (3) the best wrapping combination was A 1 B 2 C 4 ; and the best anti-wrapping combination was A 4 B 4 C 1. This paper not only provides a reliable finite element model of the leaf wrapping around the rotating roller, but also provide a foundation for the optimization and improvement of the rotating roller's anti-wrapping characteristics. [ABSTRACT FROM AUTHOR]

Aluminium alloy has recently become popular in New Zealand's construction sector as a sustainable building material. However, in roll-formed aluminium alloy (RFA) channel beams, particularly those having web holes, cripples at points of concentrated or localised loading. In this paper, end-two-flange (ETF) web crippling behaviour of RFA unlipped channels having web holes was investigated using experimental tests, numerical simulations and a deep learning model referred as deep belief network (DBN). A total of 1080 data points was generated to train the DBN, using a finite element (FE) model that was validated using 30 new experimental results reported in this paper. Compared to the test data, the DBN predictions were conservative by around 6%. Using the DBN predictions, a comprehensive parametric study was undertaken which used the validated FE model in order to explore the effects of hole size, hole location, section thickness, and bearing plate on the web crippling strength of RFA channels having web holes. Web crippling strengths obtained from the DBN, tests and finite element analysis (FEA) were utilised to evaluate the performance of current design specifications from the American Iron and Steel Institute (AISI), Australian/New Zealand Standards (AS/NZS 1664; AS/NZS 4600:2018) and Eurocode (CEN 2006, 2007). It is shown that the current design rules are not reliable to predict the web crippling strength of RFA unlipped channels with web holes. As a consequence of the parametric analysis, new web crippling strength and web crippling strength reduction factor formulae for perforated RFA unlipped channels were proposed. A reliability analysis was then conducted, which confirmed that the proposed equations are capable of predicting the ETF web crippling strength of perforated RFA unlipped channels. • ETF web crippling behaviour of roll-formed aluminium alloy channels was studied experimentally and numerically. • Finite element analysis was conducted and validated against test results. • A deep-learning model was developed to predict the web crippling strength. • A parametric study was conducted to investigate the effects of different parameters. • New design equations were proposed for web crippling strength of roll-formed aluminium alloy channels. [ABSTRACT FROM AUTHOR]

This paper aims to study the effect of controlling parameters of ultrasonic peening treatment (UPT), including the pin diameter, the vertical velocity of the pin, friction coefficient etc. on the residual stress, PEEQ and surface roughness. A method was promoted to simulate the UPT process using the ability of the ABAQUS scripting interface and transferring results between ABAQUS analyses. The finite element results of the proposed method were consistent with the UPT simulation. Moreover, the finite element results agreed well with experimental measurements of residual stress, surface roughness and surface deformation. The results revealed that increasing the pin diameter, the vertical velocity of the pin and also the number of impingements increased the depth of the compressive residual stress layer. Decreasing the vertical and horizontal velocity of the pin and increasing the pin diameter and the distance between two adjacent impingements resulted in a decline of surface roughness parameters (Ra and Rq). A combination of finite element model and multi-objective optimization technique was implemented to determine the optimum controlling parameters of UPT for reaching the maximum compressive residual stress and the minimum surface roughness. For the optimum proposed controlling UPT parameters, the values of −386 MPa, 16.7 μm and 20.9 μm were obtained for the surface residual stress, Ra and Rq, respectively. • A comprehensive experimental and numerical study on residual stress induced by ultrasonic peening treatment • A new method for simulating ultrasonic peening treatment • How controlling parameters of ultrasonic peening treatment affect the residual stresses and the surface roughness • Experimental measurement including of XRD, SEM and 3D scan • A combination of finite element model and multi-objective optimization technique to optimize controlling parameters [ABSTRACT FROM AUTHOR]

An experimental study was carried out to examine the impact-induced loads and structural responses of a three-dimensional non-prismatic aluminium wedge. The findings of the experimental study were presented in the first part of this publication, entitled "Slamming loads and responses on a non-prismatic stiffened aluminium wedge: Part I. Experimental study." This paper describes the second part of the study, which deals with numerical simulations of slamming loads acting on the wedge and its dynamic responses. Two different two-way coupling methods are assessed and compared to simulate the water entry problem. Initially, an explicit nonlinear finite element method with a Multi-Material Arbitrary Lagrangian-Eulerian (MMALE) solver is employed to evaluate the elastic response of the structure following a free-fall water impact. Subsequently, the hydroelastic slamming problem is modelled using a two-way coupled technique with a k-ε turbulence model and implicit unsteady solver for both the fluid and structural domains (Star-CCM+/ABAQUS). The effect of viscosity on slamming loads and responses was examined, and numerical results are compared with experimental data. To investigate the effect of rigidity on structural response and bottom deflection, the wedge was designed with bottom plates of varying thickness. The computed results from the two numerical models and the experimental data are in good agreement. The study concluded that the bottom plates deformation affects hydrodynamic loads during slamming. It is also observed that impact-induced loads depend on the water impact velocity and the flexibility of the bottom plates. This suggests that the slamming pressure increases with an increase in impact velocity and decreases when the structures become more flexible. According to this study, both numerical models are suitable for accurate and efficient computations of hydroelastic slamming; however, the MMALE method results in larger numerical fluctuations. • Slamming loads and responses on a non-prismatic aluminium wedge during free-fall impact are systematically studied. • Two numerical models, the MMALE and the combination of RANS CFD and FEM, are employed to simulate the FFSI problem. • The FFSI simulations are verified and compared with experimental data at various impact velocities. • An analysis of the effect of hydroelastic slamming on structural response is presented. • Maximum slamming force coefficients of 2D and 3D wedges are compared, and the three-dimensional effects are evaluated. [ABSTRACT FROM AUTHOR]

In this paper, we present a new mathematical model of the interaction of two languages. In the model, we distinguish percentages of people who speak a non-target language, a target language with low and high proficiency, and both languages considering the low and high proficiency levels in the target language. Therefore, the solution consists of five fields. Furthermore, we assume the diffusive and convective spread of the languages, considering the overflow between them. Thus, the mathematical model is defined by a coupled system of partial differential equations for the five fields. Since the mathematical model is coupled and the medium is heterogeneous, we have implemented a multiscale method. The proposed multiscale method is based on the Generalized Multiscale Finite Element Method (GMsFEM). In addition to offline multiscale basis functions, we also construct online multiscale basis functions. The online basis functions can account for changes in the heterogeneity of the medium caused by migration flows. Numerical results have shown that such online enrichment can significantly improve the accuracy of multiscale modeling. [ABSTRACT FROM AUTHOR]

In this paper the numerical simulation of the interaction between Oldroyd-B viscoelastic fluid flows and hyperelastic solids is approached. The algorithm employed is a classical block-iterative scheme, in which the solid and the fluid mechanics problems are solved sequentially. A Galerkin finite element approach has been employed for the numerical approximation of the solid, while the flow equations are approximated using a stabilized finite element method based on the Variational Multi-Scale approach to overcome the instabilities of the Galerkin method. To be able to deal with flows with dominant elasticity, a log-conformation reformulation of the constitutive equation can be employed; here this approach is extended to Fluid–Structure Interaction problems. Several numerical examples are presented and discussed to assess the robustness of the proposed scheme and its applicability to problems with viscoelastic fluids in which elasticity is dominant interacting with hyperelastic solids. [ABSTRACT FROM AUTHOR]

Microstructure features directly reflect mechanical responses during material deformation and can influence the surface integrity of machined components, which is of great interest to both academic communities and industries. This paper summarizes the state of the art in modeling approaches for the effect of the microstructures and its evolution during metal-cutting processes. The aim of this paper is to analyze the advantages and drawbacks of current methods to improve modeling work and direct future orientations. First, dominant numerical modeling approaches for metal-cutting processes are reviewed. The finite element method (FEM) and mesh-free methods widely applied in professional research are discussed. Following this, approaches to modeling the effect of microstructures and their evolution are reviewed for two major categories—homogeneous field distribution and heterogeneous characteristics. Both the advantages and disadvantages of these two categories are analyzed and discussed in detail. Experimental techniques based on advanced characterization approaches to the validation of pertinent models are also discussed. Finally, a brief summary is presented and an outlook for future work is delineated. [Display omitted] • Numerical modeling approaches with the consideration of microstructure features towards metal cutting are reviewed. • Modeling through treating microstructures as homogeneous characteristics and pertinent validation techniques are reviewed. • Modeling of heterogeneous microstructure evolution in metal-cutting and pertinent characterization techniques are reviewed. • Future orientations of modeling the effect of the microstructure and its evolution in metal-cutting are recommended. [ABSTRACT FROM AUTHOR]

The advancement of computer science has encouraged engineers and researchers to use simulation techniques for the design and evaluation of agricultural machinery and food industry equipment. The finite element method (FEM) is a numerical method used to solve complex problems, such as impact phenomena, in harvest and post-harvest processes. In this paper, the FEM procedure, elastic-plastic and viscoelastic properties of agricultural products, quasistatic and dynamic tests, and the stress generated during the post-harvest process has been reviewed. In addition, the application of FEM for the analysis of bruise volume and susceptibility is described. Finite element analysis is an appropriate method to reduce negative effects on agriculture products caused by harvesting and post-harvesting machines. This paper is intended for researchers interested in the design, optimisation, and development of harvesting or post-harvesting equipment for achieving the best final quality of the fruit. • Concept of finite element method in order to simulate the post-harvest process. • Stress analysis of different agriculture products were investigated. • Overview of static, qua-static and dynamic simulation and various impact tests. • Potential of finite element method for design food industrial systems. [ABSTRACT FROM AUTHOR]

• This paper presents a finite element analysis of cold-formed stainless steel channels with circular web holes, subjected to interior-one-flange loading condition. • To investigate the effect of web hole size, web hole location and bearing length on the web crippling strength of such sections, a parametric study involving 1,728 FE models was performed. • The parametric study results were used to propose new web crippling strength equations and strength reduction factor equations. • A reliability analysis was performed to check the reliability of proposed equations. This paper presents a numerical study on structural behaviour of cold-formed stainless steel channels with circular web holes, under interior-one-flange loading case. The material properties of stainless steel types EN 1.4509 (Ferritic), EN 1.4462 (Duplex) and EN 1.4301 (Austenitic) were taken from the literature. In order to study the influence of web hole size, web hole location and load-bearing length on the web crippling strength of such sections, a parametric study involving 1,728 finite element models was conducted. The parametric study results were used to propose new web crippling strength equations and strength reduction factor equations which performed better than those of American Society of Civil Engineers Specification (ASCE 8–02), American Iron and Steel Institute Specification and Australia/New Zealand Standard (AISI&AS/NZS) and Lian et al (2016). A reliability analysis was then carried out, and the results showed that the proposed design equations can accurately predict the web crippling strength of of cold-formed stainless steel channels with and without web holes when loaded under interior-one-flange condition. [ABSTRACT FROM AUTHOR]

This paper implements a finite-strain-based Mohr-Coulomb (MC) elasto-plastic model into the combined finite-discrete element method (FDEM) with the intrinsic cohesive zone model (ICZM). The formulation of elasto-plastic continuum elements based on the concept of unrotated configuration as the frame of reference is firstly incorporated into an in-house FDEM code, which is parallelized by general-purpose graphic processing units. The developed FDEM code can not only handle the finite elasto-plastic deformation, the large displacement, and the rotation of continuum elements but also simultaneously model the explicit rock fracturing. The split Hopkinson pressure bar (SHPB)-based dynamic tests, single-hole blasting, and model blasting experiments reported in the literature are then modeled using the FDEM with and without the MC model to elucidate the effects of the incorporation of the MC model on the dynamic rock fracturing simulation results. It is elucidated that the conventional FDEM tends to show more fractures and undesirable overestimations of local stresses and particle velocities while the proposed FDEM can reasonably avoid these issues in all the numerical simulations conducted in this study. [ABSTRACT FROM AUTHOR]

Crashworthiness optimization design of a regular ship fender structure with varying cross section fenders are studied. In this paper, new eight models of multi cell fender are selected to determine the best performance crashworthiness. To calculate the crash performance, non-linear finite element analysis is carried using the explicit ABAQUS. Therefore, this research aims to optimize the crashworthiness indicators of fenders subjected to transverse loads using NSGA II and RBF. From the simulation and optimization results, it is found that fender model 4 has the best performance, however it is recommended to change the conventional fender design. • Numerical simulations of multi-cell fender with different configurations of cross-section. • Numerical simulations of multi-cell fender under tranverse loads. • Multiobjective Optimization Design of fender using NSGA II. • Crashworthiness comparison of conventional fender using LS DYNA and ABAQUS simulation results. [ABSTRACT FROM AUTHOR]

A thermo-hydro-mechanical-damage coupled model is developed in this paper for exploring the mechanism of thermo-hydro-mechanical-damage behaviors during enhanced oil recovery. The thermo-poroelastic deformation, two-phase flow and heat transport are all solved in finite element framework. Rock damage is determined by the tensile and shear failure criterions, and the contact problem for pre-existing fractures is based on the extended finite element method and augmented Lagrangian multipliers method. Then with the numerical framework, we simulated the damage evolution, fracture activation and rock properties damage caused by the thermo-poroelastic response during water injection in enhanced oil recovery. As the water injection and oil production are carried on, damage propagation and pre-existing fracture activation gradually appear around injection well. Complex fracture-damage network system and an enhanced permeability area are observed. The expansion of damage-enhanced permeability evolution to production well will greatly affect the oil recovery. And the fracture-damage network system and enhanced permeability area evolution is highly sensitive to the injection rate, injection viscosity and injection temperature difference. The simulations and discussions demonstrated that comprehensive modelling of thermo-hydro-mechanism-damage behaviors has important significance for enhanced oil recovery and other underground liquid injection engineerings. [ABSTRACT FROM AUTHOR]

• Push-out tests of SRRAC. • The basic model of bond stress-slip curve. • Calculation formulas of bond strengths. • The bond stress-slip full curve equation. • Finite element analysis of bond-slip performance. The steel reinforced recycled aggregate concrete (SRRAC) is a kind of composite building material, and the bond performance at the interface determine the mechanical properties of the composite material. The purpose of this paper is to explore the bond performance of SRRAC. First, 43 SRRAC push-out specimens were made, and push-out tests were conducted on them. It was found that the failure process has gone through four stages. The failure patterns were found by analyzing all cracks, and the mechanism of the cracks was analyzed from the mechanical level. The basic model of load-slip curve was proposed. Secondly, the basic model of bond stress-slip curve was proposed, which was divided into four segments by three key points. The bond strength and slip of the three key points were respectively defined, and their respective calculation formulas were obtained through statistical analysis methods, which were verified by the test. Then, this paper proposed the bond stress-slip full curve equation, which was well verified by the test. Finally, detailed finite element analysis was carried out on SRRAC specimens, and the reliability of the model and the bond stress-slip full curve equation was further verified by the test. [ABSTRACT FROM AUTHOR]

[Display omitted] • Strain-sensing ability of a nanoengineered self-sensing cementitious composite is assessed by integrating multiscale finite element analysis simulations and machine learning. • Hyperparameter-optimized feed-forward multilayer perceptron-based neural network showed excellent efficacy for the prediction of strain-sensing ability. • Shapley Additive Explanations algorithm reveals that coating thickness shows higher influence on the sensing ability than fraction of coated sand. • Comprehensive approach presented here can be used as starting point toward development of reliable performance standards for self-sensing cementitious composites. Prediction of in-situ strain sensing efficiency of self-sensing cementitious composites using machine learning (ML) requires a large, representative, consistent, and accurate dataset. However, such large experimental dataset is not readily available. Moreover, the success of the ML approach depends on its ability to abide by the fundamental laws of physics. To address these challenges this paper synergistically integrates a validated finite element analysis (FEA)-based multiscale simulation framework with ML to predict the strain-sensing ability of self-sensing cementitious composites enabled by incorporating nano-engineered interfaces. The multiscale simulation framework is leveraged to develop a balanced, representative, complete, and consistent dataset containing 3000 combinations of strain-dependent electromechanical responses. This large dataset is used to predict the strain-sensing ability of the nanoengineered cementitious composites using a feed-forward multilayer perceptron-based neural network (NN) approach which shows excellent prediction efficacy. This paper also applies a Shapley Additive Explanations (SHAP) algorithm to interpret the NN predictions in light of the relative importance of different design parameters on the strain-sensing ability of the composite. Overall, the synergistic and comprehensive approach presented here can be used as a starting point toward the development of reliable performance standards to accelerate the acceptance of these self-sensing cementitious composites for large-scale applications. [ABSTRACT FROM AUTHOR]

• A user-defined elastic-plastic ice material model is implemented and used for simulating the failures during ice and steel interactions. • The sliding ice loads towards a steel hull structure are studied in detail using nonlinear finite element analysis method. • Comprehensive discussions are performed regarding the mateiral strength, local structural responses and the total friction factors. • If the ice is deformable rather than rigid, it is shown that the static friction coefficient influences the local structural responses. • It is shown that the ice floe is more constrained and difficult to fail when the hull's structural stiffness is relative low. This paper studies the hull structural responses of a steel grillage subjected to sliding ice loads, which have been rarely investigated in the literature. Sliding ice loads are modelled using nonlinear finite element analysis (NLFEA) method; and Abaqus Explicit is adopted as the numerical solver. Deformations and damages of ice and steel are both considered. A rigid ice model is also simulated for comparison purposes. The hull's local structural responses under different load cases, including deformation, contact forces, and energy distribution, have been analysed. The effects of static structure-to-structure friction coefficient and the relative stiffness between ice and structure are studied. It is found that the deformation of structures will increase the total friction coefficient, which is defined as the ratio of the friction force (the tangential contact force) to the normal contact force. When the ice floe is considered rigid, the static friction coefficient has little effect on the local structural responses of the hull. If using a higher-strength steel material for hull structures in the ice-classed ship design, the hull's deflection and total friction decrease, and the hull dissipates less energy as expected. Moreover, stationary load cases with the same loading condition in the normal direction as sliding load cases are also simulated. When using the deformable ice material model, the simulation results show that the hull's final contact forces and deflection in stationary load cases are larger than those in sliding load cases. Besides, the effect of steel material is more significant in stationary load cases than in sliding load cases. [ABSTRACT FROM AUTHOR]

The dynamic performance of vertical cylindrical storage tanks under lateral impact of explosive fragments is important for its safe loading. In this paper, the method of combining experiments and numerical simulation is employed. Based on the simplified scaled model of thin-walled cylindrical containers, the lateral impact model experiments are carried out by using the drop hammer impact tester. Typical deformations and failure modes of the structure are then obtained. After processing the experimental data to obtain the load-deformation curve and the absorption energy curve, the curves are analyzed to study the dynamical response characteristics for cylindrical containers under impact as well as the influences for container length and impact velocity on the structural dynamical response. Then, the LS-DYNA program is applied for simulating the impact procedure and its dynamic response. With the reliability of the numerical model being verified, the stress distribution of the cylindrical container during the impact process is analyzed. Through finite element parametric analyses, combined with experimental results, the influences of impact velocity, length-to-radius ratio and radius-to-thickness ratio on dynamical responses as well as failure modes of the structure are investigated. It is shown that the failure mode of the cylindrical container changes with impact velocity and radius-to-thickness ratio, but is not affected by length-to-radius ratio. The variation of peak deformation and average force of the structure with parameters such as impact velocity are obtained. • Dynamic performance of cylindrical tank under lateral impact of explosive fragments is obtained. • Dynamic response of a thin-walled cylindrical container subjected to lateral impact can be divided into four stages. • Polygonal depressed region appear in the middle of container wall with a dividing line and local wrinkles at both ends. • Failure mode of container changes with impact velocity and R/t ratio, but not affected by L/R ratio. [ABSTRACT FROM AUTHOR]

Pultruded Fiber-Reinforced Polymers (FRP) are innovative structural elements that are experiencing a steady increase in use for different structural applications. Due to their appealing properties that set them apart from traditional construction materials, such as magnetic transparency and excellent strength-to-weight ratio, numerous experimental and numerical studies have been performed in the last decades to assess their performance as structural components. The description of the micro- and macro-scale mechanical features of FRP elements requires multiple levels of information to be accurately characterized to predict their strength, and as a result, researchers have developed computational models with varying levels of complexity to parametrize their response and investigate design parameters through numerical simulations. This paper presents a critical review of the current state-of-the-art in numerical modeling of structural fiber-reinforced polymeric elements for the prediction of their mechanical behavior under serviceability and failure limit state conditions, with particular attention devoted to pultruded Glass Fiber Reinforced Polymers (GFRP), and their use as load-bearing structural elements. The most commonly adopted numerical methods for the solution of this set of problems range from classical Finite Element Method (FEM) approaches to eXtended Finite Element Method (XFEM), Virtual Crack Closure Technique (VCCT), Cohesive Zone Modeling (CZM), Multiscale Reduced Order Modeling (ROM), as well as Random Lattice Modeling (RLM) techniques recently developed by the co-authors. Each one of these methods has its own distinctive features and brings specific challenges and capabilities that will be presented and discussed in detail in the manuscript. This paper, therefore, aims at illustrating the reliability of existing numerical models for the simulation of FRP structural elements and draw conclusions and recommendations for future research, discussing 160 references from the available literature. [ABSTRACT FROM AUTHOR]

• This work studied web crippling behaviour of aluminium alloy lipped channels. • Experimental tests, finite element models, and deep neural network were built. • The effects of related factors on web crippling strength were studied. • The prediction accuracy of current design guidelines was assessed. • New formulas for web crippling strength were proposed. This work presents a deep-learning model referred to as a deep belief network (DBN) to investigate the end-two-flange (ETF) web crippling behaviour of roll-formed aluminium alloy lipped channels (both unfastened and fastened to the supports) with centred and offset web circular holes. A total of 1,080 data points was generated for training the DBN, using an elasto-plastic finite element model that was validated using 30 new experimental results presented in this paper. When the DBN predictions were compared to the experimental results, they were found to be 5% conservative on an average. A parametric analysis was then carried out using the DBN predictions, to study the effects of hole size, hole position, section thickness, and the bearing plate on web crippling strength of perforated roll-formed aluminium alloy channels. The DBN predictions were utilised to evaluate the performance of the current design rules of American Iron and Steel Institute (AISI 2016), Australian and New Zealand Standards (i.e., AS/NZS 1664, AS/NZS 4600:2018), and Eurocode (CEN 2007). The current design standards were demonstrated to be over conservative in predicting the web crippling strength of roll-formed aluminium alloy perforated channels. From the parametric analysis, new web crippling strength and web crippling strength reduction factor formulae for roll-formed aluminium alloy perforated channels were proposed. Additionally, a reliability analysis revealed that the proposed equations accurately predicted the ETF web crippling strength of roll-formed aluminium alloy perforated lipped channels. [ABSTRACT FROM AUTHOR]

• A new method for the ferrofluid second-order buoyancy is proposed by calculating the pressure of the cylindrical permanent magnet surfaces. • The two-dimensional axisymmetric model with a free boundary is calculated by the magnetic- flow coupled finite element method. • Research on the effects of free fluid surface and cylindrical permanent magnet postures on second-order buoyancy. The ferrofluid second-order buoyancy is the unique characteristic of the ferrofluid, the applications based on this characteristic were dampers, vibration absorbers, gyroscopes, and so on. At present, one of the critical steps is to obtain the accurate values of the second-order buoyancy. Previous methods only estimate the second-order buoyancy with the permanent magnet submerged in a closed container and only simulate the single magnetic field. A new method is derived by calculating the differential pressure with different surfaces of the cylindrical permanent magnet to obtain the second-order buoyancy, which is applicable for the open container in this paper. The two-dimensional axisymmetric model with a free boundary is calculated by the magnetic-flow coupled finite element method. Besides, experimental research is conducted to verify the simulation. Furthermore, it found that the free surface and the postures of the cylindrical permanent magnet will influence the second-order buoyancy. [ABSTRACT FROM AUTHOR]

Gas production from hydrates induced by depressurization is a complex thermal-hydrodynamic-mechanical–chemical (THMC) coupled process. In this paper, we present a THMC coupled model to simulate the fluid flow in hydrate-bearing sediments (HBS) and the geomechanical behavior of HBS. The model is made of two subsystems, which are the fluid part of non-isothermal multi-phase flow with hydrate kinetic and solid part of geomechanical deformation. It accounts for two-way coupling effects between these two subsystems, i.e. the effect of pore pressure and hydrate dissociation on the solid mechanical behavior and the effect of stress on the hydraulic behavior. A new numerical method based on the hybrid control volume finite element method (CVFEM)-finite element method (FEM) is developed to solve the mathematical models. The local conservative CVFEM is used for the fluid part, and the standard FEM for the solid part. In the framework of hybrid CVFEM-FEM, the local conservation is reserved and the primary variables for the two subsystem are co-located. A multi-point flux approximation (MPFA) is adopted without orthogonal meshes so that it is very flexible to build complex geometrical models. The accuracy and reliability of the newly developed simulator QIMGHyd-THMC are tested by comparing with two experimental examples and a large-scale benchmark problem of other popular simulators. • A fluid-solid coupled mathematical framework is proposed for gas hydrate production. • A hybrid control volume finite element method and finite element method is presented. • Numerical method preserves local conservation for solving of fluid subsystem. • Co-located variable for simulation of fluid and solid is achieved. • Method and software are validated by experiments and comparing with other simulators. [ABSTRACT FROM AUTHOR]

Existence of soft soil layers and high ground water level in the Qom Salt Lake area have caused deflection more than allowable limitation in Tehran- Isfahan high speed track railway. Due to reduce deflection of track railway in this area, improving the stiffness and strength of the soil beneath will be done by means of concrete pile group. But also, due to the high speed of train, resonance phenomenon is expected to happen. Despite conducting some researches on the effect of improving soft ground by pile in recent years, but there are ambiguities about performance of pile on the increasing critical speed of the track-ground system which track has been experienced large dynamic amplification as the train speed approaches that speed. So first, the bearing capacity of pile and soil layers geotechnical parameters have been determined by comparing the numerical modeling results of single pile with data obtained from in situ compressive loading test on that in this paper. Afterwards, the effect of the geometrical dimension pile group on the dynamic behavior and critical speed of track-ground system has been investigated under various speed of train (60–450 km/h) using 3D finite element model. The results indicate that resonance phenomenon has been occurred at speed of 100 km/h, which is equal to Rayleigh speed of first subgrade layer. However, improving of soil layers by pile group increases the value of the critical speed to 250 km/h. • Improving the stiffness and strength of the salty soil beneath the high-speed railway by means of concrete pile group. • Determination of bearing capacity of single pile using both field load test and FE numerical simulation. • Assessing effect of geometrical dimensions of pile group on critical speed of track-ground system. • Improving of soil layers by pile group with S/D = 5 increases the value of the critical speed to 250 km/h. • Decreasing S/D lesser than 2 has no efficiency in increasing the critical speed over 300km/h. [ABSTRACT FROM AUTHOR]

We describe a novel computational framework based on the cut finite element method (CutFEM) for process-oriented simulation in mechanized tunneling. The framework incorporates all relevant components required for the simulation of the tunnel advance process, namely the ground, the staged installation of the lining support, the tail void grouting and the tunnel boring machine. We demonstrate that CutFEM concepts can significantly facilitate the modeling, discretization and coupling of the different components, while maintaining the same accuracy as the standard boundary-fitted finite element method. The proposed CutFEM technology, which is being applied and investigated in the context of advancement simulations in mechanized tunneling for the first time, enables the seamless analysis of an arbitrary number of different tunnel alignment variants on the same structured background mesh without the need to set up a new model for each variant. This is a shift of paradigm in simulation-supported tunnel design, as the CutFEM based framework considerably facilitates a direct integration of geometric, building information and simulation models in early stages of a tunnel project. The simulation model allows for the damage assessment of the buildings during tunnel advancement with regards to different excavation scenarios, as shown in the numerical examples in this paper. [ABSTRACT FROM AUTHOR]