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This study conducts a comprehensive numerical investigation into enhancing thermal transfer within square enclosures filled with water-based oxide nanoparticle suspensions, subjected to central sinusoidal heating. Further flow configuration, influenced by an inclined magnetic field, is designed with a focus on enhancing thermal efficiency for engineering applications. Key innovations include the application of sinusoidal heating elements to enhance thermal performance significantly. Computational analysis supported by finite element analysis, quantifies the impact of these parameters on flow dynamics and thermal transmission, presenting a substantial advance in the understanding of nanofluid-filled enclosure thermal management. The study reveals that the undulation of the heating element plays a crucial role in the heat transfer rate, with improvements observed as undulation increases. The introduction of magnetic fields further controls flow distribution and buoyancy effects, as demonstrated by our findings that an increase in the Rayleigh number correlates with enhanced convection, dominating the cavity's thermal dynamics. Additionally, the report outlines the conditions under which the Nusselt number increases, indicating enhanced thermal performance. These insights are pivotal for designing optimized heat transfer systems and energy-efficient applications, setting a new benchmark for thermal management strategies in practical engineering contexts. [ABSTRACT FROM AUTHOR]

Copper (Cu) nanoparticles (NPs) and polyvinyl alcohol (PVA) are utilized to enhance heat transfer (HT) which is used in the efficiency of solar energy systems. Copper nanoparticles have excellent thermal conductivity (TC) properties that enable them to conduct heat efficiently. In this arrangement, the gap between the two cylindrical channels is settled for the hybrid nanofluids (HNFs) flow in an inclined position that is favourable to sunlight. The nanomaterials consist of a mixture of PVA and Cu nanoparticles (NPs), to execute HNFs. Solar radiation is present on the hot side of the system. The porous gap between the two channels is considered variable which plays a crucial role in enhancing heat transfer and energy conversion. The varying permeability of the gap is adjusted to control the flow resistance and improve the stability of the system. It is observed that higher porosity allows for better convective heat transfer and reduced pressure drop. The transformed equations are solved through an artificial neural network (ANN) while the control volume finite element method (CVFEM) is also used to handle the governing equations. The Cu and PVA (HNF) improves solar radiation absorption and protects components, ultimately increasing the performance and efficiency of the systems. [ABSTRACT FROM AUTHOR]

This paper presents a new computational approach to simulate challenging fluid-structure interactions (FSI) between fluids and slender deformable structures. Key innovations address limitations of standard immersed boundary methods, including spurious forces, stability at low density ratios, and accuracy at high Reynolds numbers. The method couples a sharp interface immersed boundary technique with detached eddy simulation turbulence modelling to enable precise FSI for high Reynolds number flows. A strong coupling partitioned algorithm stabilized by Aitken relaxation significantly enhances stability for low density ratios down to 1. A moving least square compact support domain approximation reduces spurious oscillations from moving geometries while providing second-order accuracy. Adaptive mesh refinement imposes jump conditions on slim deformable bodies and minimizes grid leakage. The proposed method is evaluated on three conventional FSI benchmarks and four experimental cases, confirming its robustness, accuracy, and stability in low and significantly high Reynolds numbers. A more complex fluids engineering case is considered last to test the solution under challenging conditions with fast moving solid boundaries and fast flowing fluid. A thin deformable membrane is forced through a submersible centrifugal pump under standard operating conditions. The solution is shown to produce a stable solution with good collision handling ability. [ABSTRACT FROM AUTHOR]

In micro-electro-mechanical systems, interface expansion issues are commonly encountered, and due to their small size, they often exist at the micro- or nano-scale. The influence of the micro-structural effect on interface mechanics cannot be ignored. This paper focuses on studying the impact of micro-structural effect on interface crack propagation. Modified couple stress theory (MCST) is used to study the buckling delamination of ultra-thin film-substrate systems. The equivalent elastic modulus (EEM) and equivalent flexural rigidity (EFR) are derived based on MCST. Substituting EEM and EFR into the classical Kirchhoff plate theory, the governing equations of ultra-thin film-substrate system with micro-structural effect can be obtained. The finite element method (FEM) was used to calculate the critical strain energy release rate for crack extension. Differences between the three theoretical approaches of MCST, classical theory (CT), and FEM were compared. The effects of stress ratio σ σ c , initial crack length, film thickness, and micro-structural effect parameters on crack extension were analyzed. The results show that the FEM calculations coincide with the CT calculations. The stress ratio σ σ c , initial crack length, film thickness, and micro-structural effect parameters have significantly influence crack extension. [ABSTRACT FROM AUTHOR]

A model of a sandwich magnetorheological elastomer (MRE) beam with a concentrated mass attached to one end is proposed to analyze the resonance characteristics of the cantilever beam-mass resonator. This model of sandwich MRE resonator consists of two types of components: the beam element with two nodes and four degrees of freedom and the beam element with concentrated mass. The effectiveness of this model is verified by comparing its results with existing results and finite element results. Through integrating the metamaterial beam with MRE resonators, a band-gap-adjustable metamaterial beam is proposed and low-frequency vibration suppression is achieved. The results suggest that the band gap of the structure can be effectively adjusted within a wide range by changing the external magnetic field applied to the presented MRE resonators. [ABSTRACT FROM AUTHOR]

Reconstruction for large-scale temporomandibular joint (TMJ) defects can be challenging. Previously, we utilized the medial femoral condyle (MFC) flap for TMJ reconstruction. However, the optimal fixation method remains uncertain. In this study, finite element analysis was used to study the effects of three different fixation types of bone graft: overlap type, bevel type, and flush type. Models of different fixation types of MFC flap were reconstructed from CT images. A standard internal fixation model for extracapsular condylar fracture was also included as a control. Displacement of bone graft, deformation of plates and screws, and stress distribution of plates, screws, and cortical and cancellous of the bone graft were analyzed by finite element analysis to investigate their biomechanical features. The displacement of the bone graft and deformation of plates and screws in three different fixation types showed no significant difference. The overlap type and flush type of fixation displayed the lowest and highest stress respectively. All three fixation types could satisfy the mechanical requirement and face no risk of breakage and the major displacement of the MFC bone graft. These results provide insights into the optimal fixation approach for MFC bone grafts, offering valuable guidance and reference for clinical application. [ABSTRACT FROM AUTHOR]

To compensate for thermal errors in machine tools, strategic sensor placement and rapid error calculation are crucial. This study addresses these challenges using model order reduction. A transfer function matrix and a sensitivity function were defined to optimize the number and locations of sensors without physically attaching them to the machine tool. This methodology was validated through experiments on a 3-axis machining center. The number of sensors was reduced by 50 %, and the calculations were performed instantaneously on a laptop. These results demonstrate the approach's effectiveness in advancing sensor placement strategies and real-time thermal displacement estimation. [Display omitted] • Developed sensor placement strategy for machine tools. • Reduced computation time for thermal error estimation. • Used transfer function matrix and sensitivity function. • Transfer function matrix was consistent with machine tool structure. • Thermal displacement could be estimated instantaneously without loss of accuracy. [ABSTRACT FROM AUTHOR]

Collagen fibers are the main load-bearing component of soft tissues but difficult to incorporate into models. Whilst simplified homogenization models suffice for some applications, a thorough mechanistic understanding requires accurate prediction of fiber behavior, including both detailed fiber-level strains and long-distance transmission. Our goal was to compare the performance of a continuum model of the optic nerve head (ONH) built using conventional techniques with a fiber model we recently introduced which explicitly incorporates the complex 3D organization and interaction of collagen fiber bundles [ 1 ]. To ensure a fair comparison, we constructed the continuum model with identical geometrical, structural, and boundary specifications as for the fiber model. We found that: 1) although both models accurately matched the intraocular pressure (IOP)-induced globally averaged displacement responses observed in experiments, they diverged significantly in their ability to replicate specific 3D tissue-level strain patterns. Notably, the fiber model faithfully replicated the experimentally observed depth-dependent variability of radial strain, the ring-like pattern of meridional strain, and the radial pattern of circumferential strain, whereas the continuum model failed to do so; 2) the continuum model disrupted the strain transmission along each fiber, a feature captured well by the fiber model. These results demonstrate limitations of the conventional continuum models that rely on homogenization and affine deformation assumptions, which render them incapable of capturing some complex tissue-level and fiber-level deformations. Our results show that the strengths of explicit fiber modeling help capture intricate ONH biomechanics. They potentially also help modeling other fibrous tissues. Understanding the mechanics of fibrous tissues is crucial for advancing knowledge of various diseases. This study uses the ONH as a test case to compare conventional continuum models with fiber models that explicitly account for the complex fiber structure. We found that the fiber model captured better the biomechanical behaviors at both the tissue level and the fiber level. The insights gained from this study demonstrate the significant potential of fiber models to advance our understanding of not only glaucoma pathophysiology but also other conditions involving fibrous soft tissues. This can contribute to the development of therapeutic strategies across a wide range of applications. [Display omitted] [ABSTRACT FROM AUTHOR]

In this article, we conduct a numerical simulation to investigate the failure mechanism of natural fibre–hydrogel composites under tensile deformation and swelling. Firstly, a physical-based constitutive model is chosen to describe the deformation of the hydrogel matrix. Concurrently, a macroscopic phenomenological hyperelastic constitutive model, incorporated into the material database of Abaqus, is employed to describe the mechanical responses of natural fibres. Then, we implement the model for a numerical analysis. The material parameters of the model for the hydrogel matrix and fibres are determined by a trial-and-error method from the experimental curves of pure hydrogel and fibres; the numerically simulated stress–strain curve of the composites is compared with the experimental one to verify the effectiveness of the simulation. Subsequently, several numerical analyses are performed to discuss the failure mechanism of hydrogel composites caused by the microstructural features of fibres. The findings revealed that fibre protrusion, fibre orientation deviation, and interface strength significantly affect the local failure of the composites during tensile deformation and swelling; the composites' strength and toughness mainly depend on the cooperation of various microstructural features. These results provide valuable insights into the design of fibre–hydrogel composites. [ABSTRACT FROM AUTHOR]

Currently, attempts are being made to harness wind energy by means of nonconventional electrical machines such as flux reversal machines (FRM). The main advantage of the FRM, when compared with existing synchronous generators (SG), is that all the active parts like PMs and armature windings are mounted on the stator part, whereas leaving the rotor has simple and robust. In this study, the three-phase 6/8-pole flux reversal generators (FRGs) are selected, sized, designed, and analyzed using finite element analysis (FEA). The working principle, choice of stator and rotor poles, and machine design dimensions evaluation (analytical sizing procedure), as well as relevant performance details are discussed in this paper. This study is used to analyze, a popular 6/8 pole, 0.8 kW, 50 Hz, and examine the suitability for the wind energy applications in terms of torque and power density, torque ripple, power factor, and cogging torque under 2D finite element analysis (FEA). The analysis provides an update on the current state-of-the-art and as well as future thrust areas of research necessary to bridge the gap on what is still desired for the practical application of FRMs for wind energy. [ABSTRACT FROM AUTHOR]

Grain refinement and mechanical property enhancement of cast ingot aluminum 6061 alloy were achieved using equal-channel angular pressing (ECAP) at room temperature, employing route A and route R types. Analytical, finite element and experimental methods were utilized to investigate the alloy's deformation behavior under the ECAP process. The tensile tests conducted at room temperature demonstrated a significant increase in strength with an increasing number of pressings, reaching 44.23, 53.19, and 56.7% for 1-pass, route A, and route R types 2-passes of the ECAP process, respectively. However, ductility, as indicated by elongation, gradually decreased after the first pressing. Electron backscatter diffraction was employed to reveal submicrometer grain sizes resulting from the ECAP process. The grain structure showed substantial improvement under route A and route R types at a 2-passes ECAP process. Wear tests conducted under loads of 10 and 25 N showed an increase in the coefficient of friction within the minimum wear loss intervals. Rockwell hardness also exhibited a significant increase of 119.3, 176.3, and 164.8% at 1-pass and 2-passes using routes R and A, respectively. As part of the evaluation, analytical models were computed using Python, and finite element simulations were performed using ABAQUS software. The results from analytical and finite element simulations demonstrated good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Minimizing the damage caused by landslide disasters in regions with complex geological conditions requires the development of effective and reliable methods for assessing slope stability. This study aims to generate and analyze the stability of random soil-rock mixture slope models, considering the rock block content, spatial distribution, and convexity-concavity feature of rock blocks in the slope. A Python script was developed to create these random soil-rock mixture models using the ABAQUS finite element software. Additionally, the strength reduction technique was applied to calculate the factor of safety via a USDFLD subroutine implemented in ABAQUS. A series of numerical analyses were conducted to assess the impact of rock block content and the convexity-concavity feature of rock blocks on the stability of soil-rock mixture slopes. Moreover, the impact of the random spatial distribution of rock blocks on the stability of soil-rock mixture slopes was discussed. The results show that rock block content below 20% can affect slope stability both negatively and positively. Notably, significant improvements in the stability of soil-rock mixture slopes are observed only when the rock block content exceeds 30%. Furthermore, the convexity-concavity feature of rock blocks can improve the safety factor of the slopes. This study provides a comprehensive methodology and serves as a valuable reference for estimating the safety factor of soil-rock mixture slopes using the finite element method. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to compare the biomechanical performance of endocrown-retained and post-and-core-retained fixed partial dentures (FPDs), focusing on stress distribution, tensile, and shear stress. Materials and Methods: Finite element analysis was used to simulate occlusal loading on two FPD designs: endocrown-retained zirconia and post-and-core-retained zirconia which were subjected to a simulated occlusal load of 150 N. Stress distribution was analyzed using von Mises stress, tensile stress, and shear stress. Material properties for zirconia, resin cement, enamel, dentin, bone, Periodontal ligament (PDL), and fiber post were incorporated. Results: The endocrown design showed lower von Mises stress (176.35 MPa) than the post-and-core design (298.29 MPa). It also had lower shear stress at the cement interface and reduced stress on abutment teeth. Conclusion: Endocrown-retained FPDs provide better stress distribution and structural integrity, offering a reliable, minimally invasive option for restoring endodontically treated molars. Clinical Significance: Endocrown retained 3-unit fixed partial denture can be a promising alternative to the fiber-post retained FPD for restoring molars with extensive tooth loss. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Engineering Transactions C: Aspects is the property of International Journal of Engineering (IJE) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To assess the tooth movement trends during the three stages of maxillary dentition distalization with clear aligners (CA) and to compare the efficacy of different mini‐screw anchorage systems. Materials and Methods: Three‐dimensional (3D) finite element models of three anchorage systems (A, control group; B, buccal mini‐screw anchorage group; C, palatal mini‐screw anchorage group) were established. Three stages of simulating maxillary dentition distalization with CA included maxillary molar distalization (stage 1), maxillary premolar distalization (stage 2) and maxillary anterior teeth retraction (stage 3). Therefore, a total of nine models were constructed to analyse the 3D displacement of maxillary teeth during the distalization process. Results: The displacement pattern of maxillary dentition during distalization was similar across the three groups, but with varying magnitudes. During stage 1, groups B and C exhibited greater amounts of molar distalization compared to group A. Group C also demonstrated the least amount of labial movement of the maxillary central incisor compared to the other two groups. During stage 2, the mesial displacement of the maxillary first molar was less significant in groups B and C than in group A. In the final stage, group C exhibited a greater amount of maxillary anterior retraction compared to groups A and B. Conclusion: The palatal mini‐screw anchorage system was effective in reducing anchorage loss and improving the efficacy of maxillary dentition distalization with CA. [ABSTRACT FROM AUTHOR]

This paper introduces a novel hybrid two-grid algorithm, combining the advantages of traditional two-level (Xu in SIAM J Sci Comput 15(1):231–237, 1994) and two-step (Huang in Appl Numer Math 118:75–86, 2017) method, for solving the steady magnetohydrodynamic system. This novel algorithm includes two steps: first, a low-order finite element pair is employed to solve the original problem on a coarse mesh grid, enhancing iteration efficiency and reducing computational time; second, a high order finite element pair is used to solve the linearized equations on a fine mesh grid, thereby increasing the order accuracy. After only one single correction step on a fine mesh grid, the hybrid two-grid algorithm achieves accuracy equivalent to that of using a high-order finite element pair. The stability analysis and error estimates for the hybrid two-grid algorithm are given. Ultimately, numerical experiments are conducted to demonstrate its efficiency and effectiveness. What’s more, the relative error is comparable to that of the two-level and two-step methods. Notably, this algorithm requires only minor modifications to the two traditional methods. [ABSTRACT FROM AUTHOR]

In this paper, a new connection between the H‐beam and rectangular concrete‐filled hot‐rolled‐steel tubular column (CFHRSTC) was proposed to prevent the steel beam‐column joint protruded from the inside wall in residential buildings. The quasi‐static test and finite element analysis were conducted on four new joints to study the influence of the haunch stiffener configuration, internal steel plate thickness, and axial force on the failure mode, load‐carrying capacity, ductility, energy dissipating capacity, and stiffness degradation of the joint. The results revealed that the hysteretic curve of every joint was full. The damage to the joint was concentrated in the H‐beam, and the CFHRSTC remained elastic. The joint configuration could realize a weak beam‐strong column and joint core connection. Using the haunch stiffener on two sides of the H‐beam flange could effectively optimize load transfer at the end of the H‐beam and joint core. As the axial force increased, the ultimate load‐carrying capacity and ductility gradually decreased. Reducing the thickness of the internal steel plate did not significantly influence the seismic performance of the joint. Compared with the use of cover plate joints, the use of haunch stiffeners can effectively enhance the seismic performance of joints. [ABSTRACT FROM AUTHOR]

In the present study, an improved design method is proposed for the flexural design of steel plate I‐girders at elevated temperatures. The proposed method accounts for two important phenomena accompanying the temperature increase in steel I‐girders: (1) alteration of the failure mode and (2) degradation of the material properties. The main strategy of the proposed procedure is to find the ambient‐temperature‐equivalent design parameters of steel I‐girders at elevated temperatures. The basic design relationships are adopted from the flexural design provisions of AISC 360‐16 and then modified to accommodate the elevated temperatures and instability conditions of I‐girders. To evaluate the accuracy and efficiency of the proposed method, a comprehensive finite element study is conducted using ABAQUS. To this aim, 54 numerical models of steel plate I‐girders with different cross‐section slenderness parameters were investigated. All the simulated I‐girders were prone to fail in elastic lateral‐torsional buckling mode at both ambient temperature and elevated temperatures. To corroborate the numerical modeling and analysis process at ambient and elevated temperatures, the results were verified against the available experimental data. Based on the results, the maximum absolute deviation of the ultimate flexural strength obtained from the proposed method from the finite element predictions was 9%. [ABSTRACT FROM AUTHOR]

Soil liquefaction is considered as one of the most significant issues that leads to failure of shallow and deep foundations. However, the effect of liquefaction on the seismic response of piles still poorly understood. Therefore, this research examines the seismic response of a pile embedded in soil stratum of saturated fine-grained soils. Midas GTS/NX is used to carry out the number assessment. In addition, the modified UBCSAND soil constitutive model is used to depict the nonlinear features of saturated sand during earthquake waves. The developed three-dimensional model is first validated using the results of a shaking table test of a pile embedded in coarse-grained soil, where good agreement is obtained between the finite element model and the experimental results for the displacement, acceleration, and liquefaction ratio demonstrated good agreement. Furthermore, the orientations of the vectors produced by the numerical study, that matched a global circular flow characteristic, reflected the movement of the liquefied soil all around pile. The findings showed a considerable decrease in the pile frictional resistance during the seismic events as a consequence of increasing the pore water pressure and subsequent liquefaction. Regarding this, before the soil was entirely softened, resistance due to friction was observed near the ground, in correspondence with the loose sand layer. In addition, the pile showed excessive settling, which is due to the decrease of the soil stiffness caused by the increase of the pore water pressure. The results of this research provide an insight into the mechanism of the behavior of pile in saturated coarse-grained soils and thus, it helps to improve future research on the topic and also achieve better design of piles embedded in saturated coarse-grained soils. [ABSTRACT FROM AUTHOR]

The rigid pavements and rigid base supporting rails can be considered as a strip footing resting over an embankment. In addition, there can also be single or double-strip footings resting over an embankment. These strip footings are influenced by the properties of the soil, slope angle of an embankment, setback distance, and spacing between the footings and the height of embankment. In this study, the bearing capacity factors for the single- and double-strip footings resting over an embankment are evaluated using the finite element method (FEM). The bearing capacity factors N c ′ and N γ ′ are evaluated for different soil friction angles (ϕ) , slope angles of embankment (β) , setback distances (S) , embankment heights (D) and spacing between the footings (t). Considering the practical aspect, i.e., the surcharge is not present for footing on an embankment, the N q ′ is not evaluated in the study. Based on the analysis, it is observed that the bearing capacity factors N c ′ and N γ ′ increase with increase in friction angle of the soil and setback distance and reduce with increase in the slope angle of the embankment. The effect of depth of embankment on the N c ′ and N γ ′ is negligible for smaller friction angles (ϕ ≤ 2 0 ∘) , whereas it increases marginally for higher friction angles (ϕ > 2 0 ∘). Furthermore, the N c ′ and N γ ′ are influenced by the spacing between the footings. This study's results are compared with the results available in the literature. This study's results are presented as design charts, and these could be adopted in the practice in routine designs of shallow foundations. [ABSTRACT FROM AUTHOR]

A new technology called laser shock wave-assisted nanoparticle implantation into the surface layer of a light alloy is considered. Finite element and analytical models have been developed to determine the implantation depth of WC nanoparticles into an aluminum substrate during laser shock wave implantation of nanoparticles. Two modes are considered: a single application of nanoparticle implantation technology into the surface layer, and a sequential double application of nanoparticle implantation into the surface layer. The obtained results showed that in both modes studied, nanoparticles are implanted into the surface layer of the 5A06 aluminum alloy with different intensities. It is shown that the implantation depths of nanoparticles calculated using the finite element method and the analytical model are in good agreement with the experimental data, which confirms the reliability of the developed implantation depth models. [ABSTRACT FROM AUTHOR]

Fan-out (FO) packages are in high demand for smartphones and Internet of Things (IoT) devices because they allow for the integration of multiple components within a single package, leading to enhanced functionality and improved operational performance. In addition, the shift from solder bumps to copper pillar bumps for interconnection is expected to become a prevalent trend in FO package assemblies because of their superior electrical and thermal performance and ability to achieve a finer pitch. However, the increased stiffness of the copper pillars increases the risk of interface fractures between the pillars and solder bumps during the surface mount technology process, which may degrade the thermal cycle test (TCT) reliability. Consequently, the present study develops a three-dimensional (3D) computational model, which approximates the thermomechanical properties of the redistribution layer (RDL) using the rule of mixtures principle, to analyze the reliability of the Cu pillar bumps in FO packages under thermal cycling between −55°C and 125°C. The tensile stress–strain properties of the polyimide (PI) film in the FO package are determined experimentally using an MTS Acumen microforce tester. The experimental data are used to construct an empirical formula for predicting the stress–strain response of the PI film, which is then incorporated into the simulation model. The validity of the simulation model is confirmed by comparing the predicted results for the out-of-plane deformation of the FO package with experimental observations. The reliability of the Cu pillar bumps under TCT processing is investigated numerically using the Anand viscoplastic constitutive model. Finally, a second-order response surface methodology model and Box–Wilson central composite design method are employed to determine the optimal design of the FO package that minimizes the plastic work density of the Cu pillar bumps. The results show that the thermomechanical reliability of the FO package depends mainly on the Cu trace coverage in the RDL and the thickness of the epoxy molding compound layer. [ABSTRACT FROM AUTHOR]

In Bonito (J. Comput. Phys. 448:110719, 2022), a local discontinous Galerkin method was proposed for approximating the large bending of prestrained plates, and in Bonito (IMA J. Numer. Anal. 43:627-662, 2023) the numerical properties of this method were explored. These works considered deformations driven predominantly by bending. Thus, a bending energy with a metric constraint was considered. We extend these results to the case of an energy with both a bending component and a nonconvex stretching component, and we also consider folding across a crease. The proposed discretization of this energy features a continuous finite element space, as well as the discrete Hessian used in Bonito (J. Comput. Phys. 448:110719, 2022; IMA J. Numer. Anal. 43:627-662, 2023). We establish the Γ -convergence of the discrete to the continuous energy and also present an energy-decreasing gradient flow for finding critical points of the discrete energy. Finally, we provide numerical simulations illustrating the convergence of minimizers and the capabilities of the model. [ABSTRACT FROM AUTHOR]

This study proposes sonic crystal green walls based on combined cylinder scatterers and vegetation. It has been known that the vegetation or greenery system is effective in dealing with environmental pollutants, while the cylinder scatterer arranged periodically, also known as a sonic crystal, is preferable owing to the capability of noise attenuation, light transmission, and air circulation simultaneously. Combining both components into a single noise abatement system is expected to provide acoustical and non-acoustical features for urban design, where such an approach maximizes the merit of each component. Moreover, the system is useful for advocating sustainability amid global warming issues. In this work, a numerical model is developed using finite element method (FEM), while experimental results are provided to validate the absorption and attenuation results. It is found that the sonic crystal can attain an attenuation of 13.5 dB around 1.6 kHz. Such a promising result is extended further to lower frequency under a specific configuration of scatterers corresponding to lattice distance and filling faction ratio parameters. Meanwhile, the vegetation can enhance overall attenuation at higher frequencies. [ABSTRACT FROM AUTHOR]

To investigate the concrete damage of prefabricated steel spring floating slab tracks (SSFST), a three-slab prefabricated SSFST system was established using the ABAQUS finite element software. Full trainload conditions and fatigue load conditions of a train passage were successively applied to the system. Plastic damage and fatigue damage of the floating slab were simulated based on concrete damage plasticity theory and model code, respectively. For comparison, a simulation of the fatigue experiment was conducted. Parametric analyses of the concrete strength and isolator stiffness were also performed. The results show that the maximum positive and negative bending moments of the floating slab throughout the loading stage are close in value. The positive bending moment causes stress concentration on the top slab surface which leads to plastic damage and low-cycle fatigue damage, while the negative bending moment causes middle-level elastic tensile stress on the bottom slab surface which leads to high-cycle fatigue damage. Under experimental conditions, damage on the bottom surface is much more severe, while the upper part is undamaged. Improving the concrete strength can reduce both kinds of damage, while increasing the isolator stiffness can only mitigate the high-cycle fatigue damage. Accordingly, recommendations are provided for improving fatigue experiments and structural design of prefabricated floating slabs.This study can inform the design and maintenance of the prefabricated SSFST system, ultimately enhancing their safety and longevity. [ABSTRACT FROM AUTHOR]

The metallic materials used to manufacture turbine components can potentially be replaced with ceramics such as Si3N4, but the stress on turbine discs is difficult to determine experimentally, which hinders the development and optimization of ceramics. The finite element method solves this problem, but it requires an accurate constitutive model and parameters. Existing methods for determining model parameters lack versatility and do not consider the internal pores of ceramics. This work proposes a method for determining the parameters of the high-temperature rapid fracture constitutive model of ceramics with internal pores based on the results of industrial computed tomography (CT) and high-temperature fracture toughness experiments. The constitutive model for a ceramic with internal pores was selected based on the typical service conditions of turbine discs. Industrial CT was used to measure pore information. A finite element preprocessor was developed to create simulated specimens with pores. The high-temperature fracture toughness of the ceramics was measured. Pore insensitivity was the parameter obtained from the high-temperature constitutive model of ceramics with pores using this method. The maximum relative error between the predicted and experimental flexural strengths was 6.8%. It provides a new idea for determining the parameters of constitutive models for materials with pores. [ABSTRACT FROM AUTHOR]

In this paper we discuss reduced order models for the approximation of parametric eigenvalue problems. In particular, we are interested in the presence of intersections or clusters of eigenvalues. The singularities originating by these phenomena make it hard a straightforward generalization of well-known strategies normally used for standards PDEs. We investigate how the known results extend (or not) to higher order [ABSTRACT FROM AUTHOR]

The angular coefficient method represents a valid and efficient strategy to estimate the distribution of molecules in ultra-high vacuum systems. The problem is described through a Fredholm integral equation of the second kind that is usually solved with standard numerical methods, e.g., the finite element method or the Nyström quadrature method. In this work, we aim to rigorously study the underlying integral equation in order to verify some fundamental mathematical properties and justify the application and behaviour of such numerical methods. In particular, we address to the general scenario where domains are not globally smooth. In such context, boundary corners entail poorly regular integral kernels, which in turn lead to non-Lipschitz solutions and require the adoption of non-standard analysis techniques. By introducing the concept of vacuum-connection, we can establish a methodology to prove the well-posedness of the underlying problem. Furthermore, the undermined regularity of the analytical solution and the consequent lower numerical convergence rate are proved analytically and verified through simple numerical tests. [ABSTRACT FROM AUTHOR]

Machine structure determines the performance of machine tools. The study of machine deformation contributes to the stability of machining processes, which in turn improves machining accuracy and surface quality. Vertical structure is the weak part of the horizontal micro-milling machine, which is the main source of deformation. Considering that the micro-milling cutting parameters and machine deformations are at the micron scale, it remains to be investigated whether such deformations cause changes in the cutting volume and thus affect the cutting forces. For this purpose, this paper investigates the deformation of the machine structure caused by various operating conditions and its effect on the cutting force. The finite element method (FEM) was used to calculate the deformation Δ d of the clamp-workpiece. To verify the effect of machine structure on cutting force under different working conditions, the Al 6061 full immersion slot cutting experiments were conducted by considering different cutting parameters. The results show that the deformation of the machine structure has an effect on the cutting forces, and the degree of effect varies depending on the working conditions. [ABSTRACT FROM AUTHOR]

The article presents the results of adapting the digital image correlation method for the possibility of diagnosing reinforced concrete structures. Reinforced concrete (RC) bending elements are the most widely used in construction practice, which determines the importance of reliable estimation of their stress-strain state. The purpose of this study includes reliable theoretical and experimental investigation of the strength and deformability parameters of the RC beam. The experimental study was conducted using digital image correlation and sub-micron contactless gauges. Experimental data was verified with the calculation of the stress-strain state of the RC beam according to DBN V.2.6-98:2009 and Eurocode 2 and the finite-element modelling (FEM). As a result, the values of deflections, concrete and rebar strains were obtained and presented as corresponding diagrams. The results of all the methods are within the same ranges. Also, the form and character of corresponding diagrams are very similar. The indicated deviations were within acceptable limits. It was noted that the theoretical calculation generally provides lower strain values, which is a satisfactory result, as it indicates the bearing capacity reserves provided by the current regulations. The propagation of cracks was monitored during the experiment and the measured cracks opening was compared with theoretical assumptions. Theoretical values are higher than experimental, which shows certain conservativity of valid normative regulations. The experimental and theoretical results were in good correspondence, which confirms their reliability. It was concluded, that the proposed in the study complex theoretic-experimental approach provides essential information about the strength and deformability of the structure. [ABSTRACT FROM AUTHOR]

Anthropomorphic Test Devices (ATDs) with high biofidelity and compatibility play a crucial role in vehicle safety. This study focuses on enhancing the neck of Hybrid III finite element model by optimising its design and material. The improved Hybrid III model (IH3) is validated through neck calibration tests. Comparing to experimental results,IH3 has a peak torque error of only 1.00% and 5.11%and a 60.04% improvement in calculation efficiency. Then MLH3 with low stiffness and equivalent muscles and ligaments is designed and tested. The results of MLH3 show higher biofidelity than l than Hybrid III. Finally, both IH3 and MLH3 have been tested in a 100% frontal rigid barrier test, with IH3 showing significant accuracy and computational efficiency, indicating that it could replace the current Hybrid III neck for simulation analysis. MLH3 has potential engineering application value in the future, as it improves upon the limitations of the Hybrid III neck's biofidelity and more closely resembles the real human neck. [ABSTRACT FROM AUTHOR]

To improve the safety of the children in child seats when a vehicle collision occurs, a finite element model of a child safety seat is established, and LS-DYNA is used for crash simulation. Select backrest inclination, headrest inclination, and seat belt centre height as design variables to establish response surface models. The application of chaotic mutation theory in particle swarm optimisation (PSO) is proposed, and the optimal solution of child seat parameters is obtained by using the chaotic mutation based grouped multi-objective particle swarm optimisation (MOPSO). The optimal solution was used to carry out the simulation experiment again, and compared with the original performance. It turned out that the Head Performance Criterion (HPC) is 47.08% better than the original child seat. Besides, the rib deformation is reduced by 21.30%, the neck shear stress is reduced by 55.74%, and the thigh stress is reduced by 48.55%, which indicate significant improvements. The results suggest that a certain parameter combination of the child seat leads to the optimal overall performance in child injury prevention, which indicates significant improvement in the damage of all parts of the child. [ABSTRACT FROM AUTHOR]

Solidification end reduction is an effective approach to control the central porosity during continuous casting of round bloom, although it is not widely reported. In the present work, a three-dimensional finite element model has been developed with coupling heat transfer and mechanical deformation for a φ690 mm continuously cast round bloom, and verified by the surface temperature, shrinkage zone width, reduction crack location, and deformed contour shape. It is found that the contact width between roller and the bloom increases with the increase of reduction amount and approximately in a parabolic relationship. To cover the whole range of the shrinkage zone, the total reduction amount should not be smaller than 25 mm as the width of the shrinkage zone is about 120 mm. The bulge width along the horizontal direction during reduction increases as the total reduction amount increases, and the relationship can be fitted by a parabolic equation. The reduction thickness in the shrinkage zone is larger when the reduction amount is higher, and it also follows parabolic relationship. The deformation in the shrinkage zone is more obvious when the reduction is conducted before crater end. The reduction efficiency for φ690 mm round bloom before solidification is between 20 and 30 pct, while after solidification is roughly between 12 and 20 pct. It increases with the increase of apparent reduction amount, mainly related to the increase of the strain rate. The deformation of the shrinkage zone in φ690 mm round bloom with 30 mm apparent reduction in continuous casting and hot rolling has been compared. The equivalent strain in the shrinkage zone of the round bloom in continuous casting is about 0.047 to 0.052, while that in hot rolling is about 0.031 to 0.036, indicating the reduction efficiency of the former is about 1.5 times higher than the latter. [ABSTRACT FROM AUTHOR]

For Al–Fe–Si foil stock alloys, the recrystallization behavior is one of the key features for the design of the thermo-mechanical process route, which is highly dependent on the content of the elements in solute solution, especially Fe. Consequently, the combined effects of homogenization and hot deformation on the recrystallization behavior are of great interest. The focus of this work is on the resulting recrystallization behavior during hot deformation caused by different homogenization annealings prior to hot deformation. AA8079 samples were homogenized at two different temperatures and then used for uniaxial hot-compression tests at temperatures between 320 °C and 440 °C. The resulting hot deformation and recrystallization behavior were investigated by means of flow curves, optical microscopy, and microhardness measurements. A finite element method (FEM)-based simulation model was used to compute local temperatures and strain rates. The experimental investigation revealed a significant influence of the homogenization treatment on the hot deformation flow stress and subsequent recrystallization behavior. [ABSTRACT FROM AUTHOR]

To eradicate the losses in high-frequency wireless transmission systems, glass-vias is favored over silicon-vias for the packaging of radio frequency devices. However, during machining of glass vias, poor scavenging of sludge and electrolyte scarcity in the working region degrades the ECDM performance. To cope up with these problems, this study is an attempt to induce electrolyte stirring using a magnetic stirrer in the ECDM, called S-ECDM. An electrostatic study for electrochemical cells of ECDM was performed to analyze the discharge behavior of electrodes for tool selection. A Gaussian based thermal finite element modelling (FEM) has been carried out for ECDM and S-ECDM by considering pulsed-discharges with regards to voltage, electrolyte temperature, pulse on time and partition energy. The temperature profiles were utilized in the estimation of machining rate (MR) in the micro drilling of borosilicate glass. Subsequently, simulation as well as experimental results suggested around 50% higher MR in S-ECDM than ECDM. Furthermore, characterizations have been performed to substantiate the process mechanism of the proposed process in the ambit of flushing, etching and surface roughness of micro holes. Owing to its performance and process stability, S-ECDM can be considered as a commercially viable process. [ABSTRACT FROM AUTHOR]

The fatigue life and reliability of wrought carbon steel castings produced with an optimized mold design are predicted using a finite element method integrated with reliability calculations. The optimization of the mold is carried out using MAGMASoft mainly based on porosity reduction as a response. After validating the initial mold design with experimental data, a spring flap, a common component of an automotive suspension system is designed and optimized followed by fatigue life prediction based on simulation using Fe-safe. By taking into consideration the variation in both stress and strength, the stress-strength model is used to predict the reliability of the component under fatigue loading. Under typical loading conditions of 70 kN, the analysis showed that 95% of the steel spring flaps achieve infinite life. However, under maximum loading conditions of 90 kN, reliability declined significantly, with only 65% of the spring flaps expected to withstand the stress without failure. The study also identified a safe load-induced stress of 95 MPa on the spring flap. The findings suggest that transitioning from forged to cast spring flaps is a promising option, particularly if further improvements in casting design reduce porosity to negligible levels, potentially achieving 100% reliability under typical loading conditions. This integrated approach of mold optimization coupled with reliability estimation under realistic service loading conditions offers significant potential for the casting industry to produce robust, cost-effective products. [ABSTRACT FROM AUTHOR]

Dynamic tests performed on masonry cross vaults provide important information to improve the knowledge under seismic actions of these particular structural elements. Under seismic actions, curved masonry elements show a behaviour strongly influenced by several parameters (both physical and mechanical). Their structural behaviour is hard to predict due to the significant variability of the input parameters and the strong heterogeneity of these elements. Refined nonlinear models often require specific numerical calibrations of nonlinear parameters in order to assess the structural capacity of tested element. Conversely, simplified Finite Element models represent useful tools to develop a basic knowledge on the expected structural behaviour. Initial knowledge level in SERA TA blind competition favoured simple assumptions. Therefore, the main goal was to evaluate key information of a masonry vault under dynamic action: triggering and the type of damage, the most stressed areas and the threshold at which evident damage is expected. The results obtained by these preliminary analyses have been compared with the experimental tests. [ABSTRACT FROM AUTHOR]

This paper presents the results of the blind test competition carried out within the scope of the European project SERA.ta "Seismic Response of Masonry Cross Vaults: Shaking table tests and numerical validations". The purpose of the competition was to predict the results of a set of tests carried out on an unstrengthened full-scale cross vault with mortar joints and solid bricks (then strengthened with textile reinforced mortar) subjected to a horizontal dynamic excitation. The paper offers an overview of the modelling approaches utilised, along with their corresponding predictions and post dictions. The findings are assessed based on both the damage mechanisms and predicted values for displacements and accelerations in both directions. The results are then compared with the experimental findings. Modelling approaches utilizing the Finite Element Method (FEM) yielded the most accurate predictions regarding displacements and crack patterns. Conversely, a submission employing a Discrete Element model provided the most accurate prediction of damage mechanisms. Nonetheless, the significant discrepancies in predicted displacements and accelerations underscore the necessity for continued efforts to establish consensus on appropriate modelling assumptions for masonry vaults. [ABSTRACT FROM AUTHOR]

To begin, the paper introduces methodologies employing both homogeneous continuous Finite Element Method (FEM) and block-by-block Discrete Element Method (DEM) to model masonry behaviors. In the continuous approach, the masonry is modeled as an anisotropic damageable material (homogeneous or not). In contrast, the block-based approach represents rigid blocks interacting through contact joints governed by frictional cohesive behaviors. The DEM framework allows for significant displacements, rotations, and complete detachments of blocks, aspects often overlooked in traditional FEM models. The primary application of this research involves the seismic assessment of a masonry cross vault. Notably, the numerical results exhibit the approach's capability to provide realistic predictions of failure mechanisms, crucial for retrofitting efforts. This includes an accurate representation of the actual cracking pattern, accounting for significant displacements. The numerical implementation is accessible through the open-source LMGC90 software. Comparative analyses are then carried out, focusing on the strengths and weaknesses of FEM macro-modeling (continuous homogeneous description) and DEM utilizing rigid blocks. [ABSTRACT FROM AUTHOR]

This article presents the results of the numerical simulations of a dynamic experimental campaign on the shaking table. The specimen is a full-scale masonry cross vault without and with the textile-reinforced mortar used as a strengthening solution. The specimen was tested in the scope of the European project SERA.ta 07 "Seismic Response of Masonry Cross Vaults: Shaking table tests and numerical validations". The specimen replicates a generic cross-section of a central bay located in the lateral nave of a three-nave church, where the recurrent in-plane shear mechanism is induced. Finite element model (FEM) and discrete element model (DEM) were built and calibrated based on the experimental frequencies and mode shapes. Then, a unidirectional seismic action was applied to the numerical model in order to develop shear damage in the shell of the vault. A detailed description of the two simulations and their main outcomes are presented. The response was evaluated based on the displacements, damage, collapse mechanisms and hysteretic behaviour. [ABSTRACT FROM AUTHOR]

This work presents the numerical simulations of shaking table tests of a full-scale masonry cross vault. The boundary conditions simulate the presence of a continuous lateral wall and of a colonnade-between-naves condition. The seismic action is applied along the longitudinal direction of the specimen, with increasing amplitude. The model used for the simulations allows for the elastic finite element modelling of masonry units and the discrete element modelling of the interfaces between them. A tension cut-off governs the interface: no tensile stress can be transmitted once this strength is exceeded. The shear response is defined by cohesion and friction: once the former is exceeded the interface reacts according to Coulomb's behaviour. The simulations are related to the blind predictions, according to the scheduled tests, and the post-dictions, according to the actual testing sequence. The prediction model overestimates displacements and does not catch the actual crack distribution. Therefore, a post-simulation model was implemented, revising the masonry elastic modulus as well as the stiffness and boundary conditions of the supporting piers. Simulations are improved both in terms of displacement predictions and damage mechanism. Finally, the sensitivity to finite-element size, damping ratio and block discretisation was explored. [ABSTRACT FROM AUTHOR]

This paper deals with numerical simulations on the dynamic behavior of a masonry cross vault when subjected to seismic actions. The comprehensive investigation presented here stems from the post-diction phase of a blind-prediction competition organized within the SERA project. The MADY software, specifically developed for masonry structures is used, employing a simple yet effective finite element shell model. After calibrating the model in the dynamic domain, non-linear dynamic analyses were conducted for both unstrengthened and strengthened configurations. The results were then compared with experimental data obtained from shaking table tests on the specimen; crack patterns, displacements and accelerations time histories, maximum displacements and accelerations values were assessed. The numerical simulations of the experimental tests show a fair agreement with the results. The study provides valuable insights into the challenges and potential of numerical modeling and analysis of masonry structures, highlighting the promising aspects of the MADY code. [ABSTRACT FROM AUTHOR]

Magnesium alloys are the first choice among other lightweight structural metals like aluminium, titanium and beryllium due to low density and excellent corrosion resistance. However, low slip and cold plastic processing ability limits its applications. Constrained groove pressing (CGP), one among the SPD techniques, is well suited for improving the material properties. Corrugated dies are designed to investigate the deformation behaviour of AZ31 Mg alloy samples. To minimise the number of numerical simulations, Taguchi's L9 orthogonal array is selected for the grooved die dimensions (viz. groove angle, groove width and coefficient of friction). Elasto-plastic finite element analysis is performed by implementing a multi-criterion-based genetic algorithm optimisation tool for obtaining the optimal die geometry. Reduction in total deformation, increase in the equivalent stress and elastic strain of AZ31 sheet were possible with 50° groove angle, 3 mm groove width and 0.22 friction coefficient. Mamdani-based fuzzy logic soft computing tool is implemented for the model to examine the deformation behaviour of AZ31 Mg alloy. 7.86 % deviation is observed in the fuzzy logic model predictions in comparison with simulation results. The suggested die design is well suitable for multiple CGP passes, to improve the grain refinement in the processed sheet. [ABSTRACT FROM AUTHOR]

Converting scrap tires to a useful form is becoming an acceptable technique for a broad range of applications. This study focuses on the mechanical characterisation of composites containing a high amount of waste tire rubber which are reinforced with different content of aluminium powder. Therefore, a set of experimental test is performed to highlight the effect of metallic fillers reinforcement on the mechanical response of elaborated composites under static and quasi-static tests. Results of this study reveal the high improvement of material properties for the elastomeric matrix reinforced with metallic fillers. In fact, the ultimate strength of composite material has increased to 1.8 MPa for a high reinforcement content. In the second part, a modified visco-hyperelastic model is developed on the basis of experimental results which demonstrate the prominence of the strain-rate-dependent behaviour consideration. Coupled with the Prony's series approximation, the Mooney Rivlin model is actually applied to refine the strain energy potential in order to examine the mechanical behaviour of the composite material under different loadings conditions. Finally, the good concurrence between the numerical and experimental results highlights the impressive efficacy of the proposed model in accurately predicting the mechanical characteristics of the materials under investigation. [ABSTRACT FROM AUTHOR]

This study experimentally investigated the behavior of reinforced recycled aggregate concrete (RAC) beams under monotonic and cyclic loadings to identify the advantages and shortcomings of RAC in reinforced concrete beams. Five RAC specimens and one normal aggregate concrete (NAC) specimen were tested to failure. The concrete compositions of RAC and NAC were similar; however, the coarse aggregate of RAC was recycled coarse aggregate, while that of NAC was normal stone coarse aggregate. Results indicated similarities in the failure modes of RAC and NAC beams. Compared with NAC beams, the yield and ultimate load-carrying capacities of RAC beams were only 2.6% and 8.9% lower, respectively. The cyclic loading effect negligibly induced strength degradation but decreased ductility by 9.1%. However, the yield deflection and yield stiffness of RAC beams were 22.9% higher and 30% lower than those of NAC beams, revealing their shortcomings. The above results emphasized the potential use of RAC in structural members by addressing the high deformation characteristic of RAC (e.g., modifying the concrete composition to increase the compressive strength of RAC). The nonlinear analytical method of NAC beams, in which the fiber model and the finite element method were finally combined, can be used for RAC beam analysis with acceptable accuracy. [ABSTRACT FROM AUTHOR]

This study established a finite element model to assess the impact of various transverse strengthening techniques on the Xiuzhen River Bridge, a prestressed concrete box-girder bridge. On-site experiments validated the effectiveness of the finite element model. Five different strengthening techniques, namely, adding steel or concrete diaphragms (ASD or ACD), adding composite truss (ACT), strengthening bridge deck (SBD), and setting transverse prestress (STP), were compared. The results demonstrated a significant reduction in the deflection of the bridge using these techniques. SBD technology exhibited the highest deflection reduction rate at 47.91%, and STP technology achieved a maximum reduction rate of 53.92% in the presence of initial bridge damage. In addition, these techniques notably improved the lateral integrity from the load distribution factor (LDF). However, relying solely on the LDF cannot discern the most effective strengthening method. Therefore, a combined LDF and Kullback–Leibler divergence method was proposed to comprehensively analyse the relative entropy (RE) between different models. The results highlighted that SBD technology significantly reduced the RE of the bridge by 82.94%. In the presence of initial damage, ACT technology demonstrated significant stability in reducing the RE, with a sensitivity of only 10.98%. For newly constructed bridges, SBD technology is notably effective; however, for existing bridges, ACT technology may be a reasonable choice. Additionally, an investigation of failure modes emphasized that all the models exhibit similar failure modes, with initial damage and the implementation of different techniques primarily affecting cracking and ultimate load rather than significantly altering the overall failure mode. [ABSTRACT FROM AUTHOR]

This study addresses the research gap regarding using natural fibre-reinforced polymers (FRPs) to construct hybrid Double-Skin Tubular Columns (DSTCs). Experimental testing on twelve rectangular specimens revealed critical failure mechanisms primarily due to the rupture of FRP tubes under excessive stress. This rupture led to the loss of lateral support for the concrete, resulting in severe crushing and localized buckling of the inner steel tube. The experimental results also showed an 18% increase in axial stress and 18 times enhancement in axial strain within confined concrete specimens compared to unconfined concrete specimens because of the effective confinement provided by the outer natural FRP tube (hemp fibre). By integrating experimental and nonlinear finite element simulations, this study highlights the structural performance of these hybrid DSTCs under axial compression, with an average deviation of 1% at the peak axial load, demonstrating the effectiveness of the numerical simulation model. Additionally, a parametric study using validated nonlinear finite element analysis (NLFEA) models to investigate the influence of outer tube cross-sectional aspect ratio, inner steel tube shape, and outer FRP tube thickness on the confined concrete in rectangular DSTCs has been carried out. The finding highlighted that rectangular DSTCs with thicker FRP tubes exhibit higher ultimate axial stress and strain in the confined concrete. Moreover, rectangular DSTCs with square inner steel tubes showed notably lower ultimate axial stress and strain in the confined concrete than rectangular DSTCs with circular inner steel tubes. This comprehensive study emphasizes the importance of stress–strain models, offering valuable insights for the design and construction of hybrid rectangular DSTCs. [ABSTRACT FROM AUTHOR]

Two precast shear walls connected by sleeve and high-strength threaded rod connectors and a precast shear wall connected by grouting sleeves were tested under cyclic loading. The results show that, compared with the precast shear wall connected by the grouting sleeve, the ductility of the new type of shear wall increased by 16.7%, the energy dissipation capacity decreased by 3%, and the bearing capacity and stiffness degradation ability were similar. A finite element parameter analysis was conducted, studying the effects of the axial compression ratio and shear span ratio on the performance of the new type of precast shear wall. The results show that as the axial compression ratio increased from 0.1 to 0.3, the bearing capacity increased by 21.8%, and the peak load displacement decreased by 36.1%. As the shear span ratio increased from 1.09 to 1.82, the failure mode of the specimen showed a trend of changing from shear-compression failure to bending failure. In addition, based on the experimental results and simulation results, a calculation formula for the lateral bearing capacity of shear walls has been proposed, providing a basis for the design of new types of shear walls. [ABSTRACT FROM AUTHOR]

We propose MiNNIE, a simple yet comprehensive framework for real-time simulation of nonlinear near-incompressible elastics. To avoid the common volumetric locking issues at high Poisson's ratios of linear finite element methods (FEM), we build MiNNIE upon a mixed FEM framework and further incorporate a pressure stabilization term to ensure excellent convergence of multigrid solvers. Our pressure stabilization strategy injects bounded influence on nodal displacement which can be eliminated using a quasiNewton method. MiNNIE has a specially tailored GPU multigrid solver including a modified skinning-space interpolation scheme, a novel vertex Vanka smoother, and an efficient dense solver using Schur complement. MiNNIE supports various elastic material models and simulates them in real-time, supporting a full range of Poisson's ratios up to 0.5 while handling large deformations, element inversions, and self-collisions at the same time. [ABSTRACT FROM AUTHOR]

This work presents a monolithic finite element strategy for the accurate solution of strongly‐coupled fluid‐structure‐electrostatics interaction problems involving a compressible fluid. The complete set of equations for a compressible fluid is employed within the framework of the arbitrary Lagrangian–Eulerian (ALE) fluid formulation on the reference configuration. The proposed numerical approach incorporates geometric nonlinearities of both the structural and fluid domains, and can thus be used for investigating dynamic pull‐in phenomena and squeeze film damping in high aspect‐ratio micro‐electro‐mechanical systems (MEMS) structures immersed in a compressible fluid. Through various illustrative examples, we demonstrate the significant influence of fluid compressibility on the dynamics of MEMS devices subjected to constrained geometry and/or high‐frequency electrostatic actuation. Moreover, we compare the proposed formulation with the nonlinear compressible Reynolds equation and highlight that, particularly at low pressures and high fluid viscosity, the Reynolds equation fails to provide a reliable approximation to the complete set of equations utilized in our proposed formulation. [ABSTRACT FROM AUTHOR]