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This work presents large‐scale elasto‐plastic topology optimization for design of structures with maximized energy absorption and tailored mechanical response. The implementation uses parallel computations to address multi million element three‐dimensional problems. Design updates are generated using the gradient‐based method of moving asymptotes and the material is modeled using small strain, nonlinear isotropic hardening wherein the coaxiality between the plastic strain rate and stress is exploited. This formulation renders an efficient state solve and we demonstrate that the adjoint sensitivity scheme resembles that of the state update. Furthermore, the KKT condition is enforced directly into the path dependent adjoint sensitivity analysis which eliminates the need of monitoring the elasto‐plastic switches when calculating the gradients and provides a straight forward framework for elasto‐plastic topology optimization. Numerical examples show that structures discretized using several millions degrees of freedom and loaded in multiple load steps can be designed within a reasonable time frame. [ABSTRACT FROM AUTHOR]

Accurate modeling of layered composite structures often requires the use of detailed finite element models which can sufficiently resolve the kinematics and material behavior within each layer of the composite. However, individually discretizing each material layer into finite elements presents a prohibitive computational expensive given the large number of thin layers comprising some laminated composites. To address these challenges, an 8‐node layered solid hexahedral finite element is formulated with the aim of striking an appropriate balance between efficiency and fidelity. The element is discretized into an arbitrary number of distinct material layers, and employs reduced in‐plane integration within each layer. The chosen reduced integration scheme is supplemented by a novel physical stabilization approach which includes layerwise enhancements to mitigate various forms of locking phenomena. The proposed framework additionally supports the inclusion of interlaminar enhanced displacements to better represent the kinematics of general layered composite materials. The described element formulation has been implemented in the ParaDyn finite element code, and its efficacy for modeling laminated composite structures is demonstrated on a variety of verification problems. [ABSTRACT FROM AUTHOR]

Summary: This article documents a cut‐cell finite element method for solving Poisson's equation in smooth three‐dimensional domains using a uniform, Cartesian axis‐aligned grid. Neumann boundary conditions are imposed weakly by way of a Delaunay triangulation, while Dirichlet boundary conditions are imposed strongly using a projection method. A set of numerical simulations demonstrates the proposed method is robust and preserves the asymptotic rate of convergence expected of corresponding body‐fitted methods. [ABSTRACT FROM AUTHOR]

In this work, a low‐order virtual element method (VEM) with adaptive meshing is applied for thermodynamic topology optimization with linear elastic material for the two‐dimensional case. VEM has various significant advantages compared to other numerical discretization techniques, for example the finite element method (FEM). One advantage is the flexibility to use arbitrary shaped elements including the possibility to add nodes on the fly during simulation, which opens a new variety of application fields. The latter mentioned feature is used in this publication to propose an adaptive mesh‐refinement strategy during the thermodynamic optimization procedure and investigate its feasibility. The thermodynamic topology optimization (TTO) includes a efficient gradient‐enhanced approach to regularization of the otherwise ill‐posed density based topology optimization approach and was already applied to various material models in combination with finite elements. However, the special numerical treatment leading to efficiency of the regularization approach within the TTO has to be modified to be applicable to VEM, which is presented in the publication. We show the performance of this framework by investigating several numerical results on benchmark problems. [ABSTRACT FROM AUTHOR]

The current paper introduces a new stabilization scheme for void and low‐density elements for geometrical nonlinear topology optimization. Frequently, certain localized regions in the geometrical nonlinear finite element analysis of the topology optimization have excessive artificial distortions due to the low stiffness of the void and low‐density elements. The present stabilization applies a hyperelastic constitutive material model for the numerical stabilization that is associated with the condition number of the deformation gradient and thereby, is associated with the numerical conditioning of the mapping between current configuration and reference configuration of the underlying continuum mechanics on a constitutive material model level. The stabilization method is independent upon the topology design variables during the optimization iterations. Numerical parametric studies show that the parameters for the constitutive hyperelasticity material of the new stabilization scheme are governed by the stiffness of the constitutive model of the initial physical system. The parametric studies also show that the stabilization scheme is independently upon the type of constitutive model of the physical system and the element types applied for the finite element modeling. The new stabilization scheme is numerical verified using both academic reference examples and industrial applications. The numerical examples show that the number of optimization iterations is significantly reduced compared to the stabilization approaches previously reported in the literature. [ABSTRACT FROM AUTHOR]

A novel dental fiber post from glass fiber‐reinforced polybenzoxazine (PBZ) composites was developed in this work. The essential properties, that is, chemical characteristics, thermal and biological properties of the PBZ composites were investigated for various glass fiber loadings (10.5, 23.7, 41.2 and 65.1 vol%). Finite element analysis (FEA) was also utilized to observe mechanical behaviors of the tooth model repaired with PBZ composite posts compared to a natural tooth model. The findings reveal that for the fiber‐reinforced PBZ composites not only their thermal properties were significantly improved, but they also showed enhanced cytocompatibility; we found a coefficient of thermal expansion of 12.8 ppm/°C and cell viability of 91.55 for the 65.1 vol% glass fiber‐reinforced PBZ composite. Moreover, samples reinforced with higher glass fiber loadings effectively resulted in the reduction of stress distribution in dentin observed from FEA suggesting protection againt root fractures. Restoration using the PBZ composite post showed the same stress patterns in the dentin‐composite resin‐post interface of the repaired tooth as in the natural tooth model. The results revealed that the glass fiber‐reinforced PBZ composites possess good thermal properties and mechanical behaviors which renders them suitable candidates for biocompatible dental materials. Highlights: The glass fiber/polybenzoxazine (GF/PBZ) composites had nontoxic properties as evidenced through cell viability, growth and morphology studies.The thermal expansion of the GF/PBZ composite was similar to that of dentin, promoting adaptation at the dentin‐post interface.Mechanical behaviors evaluated by FEA of tooth model restored with GF/PBZ composite post were similar to those restored with commercial glass fiber post.The biocompatible GF/PBZ composite with good thermal and mechanical properties is a promising new candidate material as dental fiber post. [ABSTRACT FROM AUTHOR]

One of the main issues in epoxy‐based composite manufacturing is the formation of porosity derived from moisture absorption during storage and layup due to the high hydrophilicity of epoxy matrices. During the curing process, the presence of moisture and other volatile compounds can initiate the nucleation and growth of voids. In this study, the effect of both the initial water content absorbed in the uncured resin and the pressure on the porosity development in an epoxy resin was investigated. In particular, Kardos' and Ledru's models, aimed at predicting void formation in polymers, were applied to study the effect of different hydrostatic pressures in an epoxy resin during curing up to the gel point, after conditioning it at two different relative humidity levels, 50% and 95%. Subsequently, the porosity of the cured resin samples was quantified through density measurements. Comparative analysis of the microscopy images of cured samples and the predictions of both models revealed an overestimation of the final void sizes by both models, with the Kardos' model exhibiting a higher deviation. Additionally, a finite element model was employed to investigate the conditions leading to void formation, aiming to understand the factors influencing the porosity development and properly set the process parameters during composite manufacturing. Highlights: Evaluation of the conditions leading to void growth in epoxy resin during curingMoisture sorption in uncured epoxy resinEffect of curing pressure on pore developmentFinite element analysis for void growth during resin curing [ABSTRACT FROM AUTHOR]

Clamped single edge notched tensile (SENT) specimens are widely used in fracture toughness test and fatigue crack growth experiment of structural materials. However, the existing fracture parameters of clamped SENT specimens are all based on isotropic conditions, which limits the application of anisotropic materials. In this study, a systematic finite element analysis of orthotropic clamped SENT specimens was carried out to determine the stress intensity factor (K) and compliance (C). A wide range of orthotropic and geometric parameters, including crack length over width ratio (a/W), daylight to width ratio (H/W), and material parameters λ and ρ, were considered. The coupling effects of material parameters and geometrical dimensions on fracture properties were then investigated. Results showed that the K and C increase with the increase of a/W and H/W, and decrease with the increase of λ and ρ. The value of C is more sensitive to changes of orthotropic and geometric parameters than the K. Moreover, the accurate solutions for normalized K, C and compliance‐based crack length prediction were developed. Applications of the proposed solutions on experimental data were presented and discussed. The current results will help to accurately calculate the fracture toughness or FCG rate of composites, further advancing the standardization process of composites testing based on SENT specimens. Highlights: Evaluate the K and Compliance for orthotropic single edge notched tensile (SENT) specimens using 2D finite element analysis;The coupling effects of orthotropic parameters and geometric sizes are studied;Develop prediction equations for K and C of clamped SENT specimen;Propose a universal crack length estimation method based on the compliance;Discuss the application of the proposed equations to the tested data of UD CFRP. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study on anisotropic heat transmission behaviors in quartz fiber fabrics. Considering the random distribution characteristic of fibers within the yarn, an innovative two‐scale finite element method (tFEM) is introduced, incorporating multiple micro‐scale fiber models (MMFM) based on scanning electron microscope (SEM) observations. MMFM are divided into 8 distinct models to capture intricate fiber arrangements. The macro‐scale fabric model is constructed based on the geometric structure analysis by Micro‐CT technology. Both micro‐ and macro‐scale models are assembled with the air matrix to form the two‐phase composite model. The Hot‐Disk thermal analysis instrument is applied to measure the anisotropic thermal conductivity (ATC). Numerical results from MMFM shows more excellent agreements with the experimental ones at 3D orthogonal directions of fabrics, i.e., the error rates of the thermal conductivity in the warp, weft and thickness directions between numerical and experimental methods are all less than 3%, which indicates the tFEM including MMFM in this paper is more accurate than the tFEM including OSMFM. In addition, the temperature distribution and heat transmission differences due to fiber arrangements are simulated and illustrated through the MMFM. Afterwards, temperature drop and isothermal characteristics are demonstrated in this study. Highlights: Effects of fiber arrangements on steady heat transfer behaviors at micro‐scale are illustrated.Isothermal and temperature‐drop characteristics at micro‐ and macro‐scale are simulated and studied.The transverse isotropy of thermal conductivity at micro‐scale and the anisotropy of that at macro‐scale are revealed. [ABSTRACT FROM AUTHOR]

Activated carbon cold adsorbed H 2 storage (CAH2) is a promising physical hydrogen storage method. However, conventional storage tanks face problems of local high heat accumulation during the cold adsorption process, leading to low hydrogen storage efficiency and capacity. This study attempts to design high thermal conductivity fins to a conventional CAH2 tank to enhance heat and mass transfer, thereby promoting the hydrogen adsorption process. An accurate mathematical model and finite element method are established to calculate the CAH2 process. The influence mechanism of different fin arrangements, fin length, fin number (spacing), and fin width on the temperature field, adsorption concentration field and storage performance are explored. The results show that adding fins can effectively promote heat transfer and suppress local high temperature and low adsorption concentration areas. When the adsorption mass reaches 0.05 kg, the storage efficiency of the three tank schemes with added fins improves by approximately 40% compared with the original tank. Although extending the fin length will enhance heat conduction, it will also suppress the heat convective transfer effect. The optimal fin length is found to be 30 mm. Increasing the number of fins (reducing spacing) can significantly decrease the areas of local high temperature and low adsorption concentration, but this beneficial effect diminished when the number of fins exceeded 14. Increasing the fin width has a weaker beneficial effect on the temperature field and adsorption concentration field, and also cause a significant reduction in the tank volume, thereby reducing the total hydrogen storage capacity. The findings of this study can provide important guidance for the application of high thermal conductivity fins in CAH2 tanks. • The effect of adding fins on hydrogen adsorption process is explored. Dynamic temperature evolution. •The influence mechanism of different fin forms on heat transfer process is analyzed. •Most reasonable fin layout scheme and size parameters are obtained. •Adding fins can increase the hydrogen storage efficiency by more than 40%. [ABSTRACT FROM AUTHOR]

Background: This study aimed to analyze the effects of maxillary molar distalization using clear aligners with different intramaxillary and intermaxillary traction via the three-dimensional (3D) finite element method. Methods: A 3D finite element model consisting of the maxilla, mandible, dentitions, periodontal ligaments (PDLs), attachments, and clear aligners was constructed. Five groups were established based on different traction modalities: group 1 (control group); group 2 (orthodontic mini-implants (OMIs) were implanted between the maxillary first molars and the second premolars on the buccal side); group 3 (OMIs were implanted in the infrazygomatic crest area between the maxillary first and second molars on the buccal side); group 4 (OMIs were implanted between the maxillary first molars and the second premolars on the palatal side); and group 5 (class II elastics were utilized between the maxillary canines and the mandibular first molars). OMIs were implanted 4 mm away from the alveolar crest in each experimental group. A force of 1.5 N was applied to each experimental group. The 3D displacement of the target teeth and stress distribution around the PDLs were analyzed. Results: Group 4 exhibited the least amount of torque change in the upper anterior teeth and the highest displacement of the maxillary second molars. Group 3 showed smaller changes in anterior teeth torque and higher molar distalization efficiency compared to group 2. Group 5 showed adverse effects such as anterior teeth extrusion and mandibular anchorage loss. Conclusion: OMIs implanted on the palatal side have advantages in preserving anterior teeth anchorage and improving the efficiency of molar distalization compared to those positioned on the buccal side. OMIs implanted in the infrazygomatic crest area between the first and second molars on the buccal side demonstrate benefits in the aforementioned aspects when compared to OMIs implanted between the first molars and the second premolars on the buccal side. [ABSTRACT FROM AUTHOR]

ABSTRACT It remains inconclusive about the stability and optimal fixation scheme of screw internal fixation for lateral malleolus oblique fractures in clinical practice. In this study, the effects of different screw internal fixation methods on the biomechanics of lateral malleolus oblique fractures were investigated. These efforts are expected to lay a theoretical foundation for the selection of internal fixation methods and rehabilitation training regimens in the treatment of lateral malleolus fractures. A healthy ankle joint model and a lateral malleolus fracture internal fixation model were established based on CT data with the aid of some software. Besides, the effects of screw internal fixation modalities on the fracture displacement of fibula fractures, fibula Von Mises stress, and screw Von Mises stress under different physiological conditions and loading conditions were investigated using finite element methods (FEMs) and in vitro physical experiments. The double screw vertical fibular axis internal fixation approach had the lowest fracture displacement of fibula fractures and screw Von Mises stress values; while the double screw vertical fracture line internal fixation approach had the lowest fibula Von Mises stress values. Under different physiological conditions, the magnitude of the peak Von Mises stress of the fibula and screw was ranked as plantarflexion 20° > plantarflexion 10° > neutral position > dorsiflexion 10° > dorsiflexion 20°; and the magnitude of the peak displacement of the fibula fracture breaks was ranked as plantarflexion 20° > plantarflexion 10° > neutral position > dorsiflexion 20° > dorsiflexion 10°. The results of in vitro physical experiments and finite element analyses were in good agreement, which validated the validity of finite element analyses. The vertical fracture line screw implantation method displays a better load‐sharing ability; while the vertical fibular axis screw implantation method exhibits a better ability to prevent axial shortening of the fibula and also reduces the risk of screw fatigue damage. Overall, the double screw achieves better therapeutic effects than the single screw. Given that the ankle joint has high stability in the dorsiflexion position, it is recommended to prioritize dorsiflexion rehabilitation training, rather than dorsiflexion and plantarflexion rehabilitation training with too large angles, in the treatment of lateral malleolus fractures. [ABSTRACT FROM AUTHOR]

In this paper, we explore the effectiveness of strategies for mitigating urban warming from a numerical simulation standpoint. To achieve this, a reinterpretation of porosity on an urban context allows us to identify the urban surface covered by streets, and the urban surface covered by buildings as the fluid and solid phases of an urban-porous media, respectively. Using a Gaussian distribution we define the urban porosity at all points within an urban zone. Once the urban porosity is defined, a Darcy-Brinkman-Forchheimer type model is coupled with a thermal exchange model to obtain the wind field, and the air temperature. The convective nature of the model, and the porosity gradients lead us to use stabilized finite element methods in order to avoid the appearance of spurious oscillations in numerical solutions: we use a pressure stabilizer for the Darcy-Brinkman-Forchheimer model and a least-squares stabilizer for the thermal exchange model. Numerical experiments were conducted on a domain modeled after the Metropolitan Zone of Guadalajara City, Mexico, to evaluate strategies such as white roofs, concrete-paved streets instead of asphalt, and large urban parks. The results reveal significant differences in urban temperatures, which in turn helps to alleviate thermal stress for city inhabitants. [ABSTRACT FROM AUTHOR]

Highlights In this study, the impact performance of carbon fiber‐reinforced polymer (CFRP) composites under low‐speed impact conditions was investigated using a data‐driven approach. Both material properties and impact parameters were determined through experimental methods and finite element (FE) analysis. FE analysis was conducted on CFRP composite structures to generate impact force and absorbed energy datasets. Various impact conditions, such as impactor height (0.5–1.25 m), impactor shape (flat, truncated cone, bullet, and cone), and composite plate thickness (1–4 mm), were incorporated into an artificial neural network (ANN) model to predict the impact behavior of CFRP composites. Using the optimal plate thickness identified from the data‐driven model, CFRP plates were fabricated using vacuum‐assisted resin transfer molding and tested under different impactor shapes and heights using drop impactors. The FE analysis revealed that increasing the impactor height improved the impact force by 37.8% and the absorbed energy by 178%. The impactor shape also significantly influenced the results, with a flat‐to‐cone‐shaped impactor increasing the impact force and absorbed energy by 167.2% and 440%, respectively. Additionally, the plate thickness analysis showed that a 2 mm plate provided optimal impact force and absorbed energy, with values of 1.09 kN and 8.12 J, respectively. The prediction of the force and energy experienced by CFRP material under different impact conditions was validated using root mean squared error (RMSE), mean square error (MSE), mean absolute error (MAE), and R2 metrics. The model demonstrated excellent performance with the lowest RMSE (0.0118), MSE (0.0003), and MAE (0.0096), indicating that the predicted impact forces closely matched the actual forces. The highest R2 value (0.9999) suggests that the model accurately captures the variance in impact force across varied impact conditions. Similarly, R2 values close to one indicate that the model effectively explains the variability in energy absorption, making it highly reliable. The ANN model also showed that predictions for absorbed energy were more accurate than those for impact force under varying impact conditions. Furthermore, the predicted impact force and absorbed energy from the FE analysis and ANN model closely aligned with the experimental results. Damage morphology observations indicated matrix cracking at higher impact velocities, with more significant penetration occurring with cone‐shaped impactors. These findings demonstrate a strong correlation between experimental and numerical outcomes, validating the effectiveness of this combined approach for evaluating the impact resistance of CFRP composites. The impact performance of CFRP composites under different impact conditions was modeled. An Artificial Neural Network model was developed to predict impact performance. The VARTM method was adopted for the development of optimized CFRP composites. Impactor height and shape were found to be the most influential factors Impact damage areas were related based on impactor height and shape. [ABSTRACT FROM AUTHOR]

The need for advanced materials that can meet application requirements at ultra-high temperatures in oxidizing environments is an area of active research. One challenge facing the high temperature materials community is the ability to conduct controlled ultra-high temperature oxidation tests with minimal to no contamination or reaction with the chamber. A unique resistive heating system (RHS) capable of achieving ultra-high temperatures (> 1700 °C) to enable such experimentation is described. A concern of such a system is the potential presence of thermal gradients in directions not reflective of actual material applications, e.g., the hottest region being in the center of the sample. Experimental results from the oxidation of ZrB2 specimens at nominal temperatures of 1500°, 1700° and 1800 °C in low pO2 (0.1–1% O2 in Ar) environments are presented. Specimen thermal gradients generated during oxidation were evaluated using finite element analysis models. Thermal gradients on the order of the uncertainty in temperature measurements were calculated, confirming the RHS suitability for conducting ultra-high temperature oxidation exposures on ultra-high temperature ceramics. [ABSTRACT FROM AUTHOR]

Purpose: Vibration isolator combining the mechanical metamaterials could greatly improve the vibration isolation and sound suppression performances due to the extreme vibration attenuation in the forbidden bandgaps. The structure design, vibration and sound radiation analysis of the traditional isolator co-existing the Bragg and locally resonant metamaterials has attracted wide attention. The paper presents a novel integrated absorber periodic layered isolator, where the periodic layered isolator shows the Bragg scattering effect and the integrated absorber shows the locally resonant effect. The designed integrated periodic layered isolator combines periodic metal layer and rubber layer in adjacent and periodically embeds metal thin plate and metal ring block as absorber in metal layer. Method: Finite element method (FEM) analysis and the experimental validation of the proposed integrated absorber periodic layered isolator are carried out comparing to those of the periodic layered isolator. Furthermore, the influences of the structural parameter of the integrated absorber periodic layered isolator on the bandgap characteristic are investigated. Results: The results demonstrate that the integrated absorber periodic layered isolator increases a low-frequency bandgap comparing to the periodic layered isolator. The vibration responses of the two periodic isolators have broadband vibration attenuation at middle and high frequencies, while the vibration response of the integrated absorber periodic layered isolator obviously fall in low frequency bandgap. The sound radiation suppression of the integrated absorber periodic layered isolator performs better than that of the periodic layered isolator in the frequencies of the bandgaps. The parametrical analysis shows that the bandgap structure could be adjusted by the structural parameters of the proposed isolator. With different structural parameters, the bandgap coverages of the integrated absorber periodic layered isolators show around 70% while those of the periodic layered isolators show around 60% below 3000 Hz. Conclusion: The integrated absorber periodic layered isolator opens the low frequency bandgap which is more suitable for vibration isolation at low frequency in engineering application. [ABSTRACT FROM AUTHOR]

This paper presents an energy stable scheme for the numerical solution of the Allen–Cahn equation. The scheme combines the Crank–Nicolson/Adams–Bashforth technique with the Galerkin method, complementing a thoughtfully designed stabilization term. While the Allen–Cahn equation is inherently nonlinear, our proposed algorithm effectively addresses this nonlinearity by utilizing the implicit nature of the resulting system of equations. Additionally, the ${L^2}$ L 2 error estimate for the fully discretized scheme is carried out in a rigorous way with the optimal error bound $O({\tau ^2} + {h^{r + 1}})$ O (τ 2 + h r + 1 ). This analysis demonstrates the precision and accuracy of our approach. In tandem with the theoretical framework, we conduct comprehensive numerical experiments to assess the practical validity of our method. Our findings not only validate the theoretical results but also reveal an intriguing observation: the judiciously chosen stabilization term significantly enhances the performance of the model. This finding underscores the practical effectiveness of our proposed scheme, which consistently produces precise and reliable solutions, reaffirming existing evidence. [ABSTRACT FROM AUTHOR]

This paper presents large deformation finite element (FE) modelling of penetration of solid cylindrical piles into highly sensitive soft clay. The simulations are performed using a Coupled Eulerian–Lagrangian (CEL) FE modeling technique. The pile is penetrated at a constant rate, and the analyses are performed for undrained conditions to simulate the response during penetration. The soil model considers the effects of strain softening and strain rate on the undrained shear strength. The FE-calculated results are compared with available analytical and numerical solutions for idealized soil profiles. Simulations are also performed for two instrumented piles previously installed into highly sensitive clay at Saint-Alban in Québec, Canada. The installation-induced changes in stresses, degradation of undrained shear strength, and tip resistance obtained from FE analyses are consistent with the field test results. Large plastic shear strains develop near the pile, which can significantly remould the soil near the pile shaft. A parametric study shows that a quicker post-peak degradation of undrained shear strength of highly sensitive clay creates a smaller zone of high plastic shear strain near the pile, while the plastic zone is wider for low- to non-sensitive clays. [ABSTRACT FROM AUTHOR]

This study presents an improved in-flight strutting system for centrifuge modelling. Based on the centrifuge model test data, the mobilizable strength design (MSD) method was revised. The modified MSD method extends to the prediction of three-dimensional (3D) deformations in retaining walls due to excavation activities. Initially, an improved in-flight excavation tool used in centrifuge tests was employed to investigate the impacts of staged excavation on the characteristics of wall displacement and ground settlement in two-dimensional (2D) braced excavation. Subsequently, 2D and 3D finite element analyses, calibrated against the centrifuge test data and considering the small strain effect, were conducted to assess the performance of wall displacement, ground settlement, and movement of the underground soil induced by the braced excavation. Moreover, this research proposes a straightforward predictive model based on the modified MSD, specifically for calculating the deformation along the length of retaining walls in 3D braced excavations. The insights and the modified MSD method given in this study may facilitate the design of foundation pit projects, especially when the 3D effects are an essential detail to be considered in these projects. [ABSTRACT FROM AUTHOR]

The importance of developing simple relationships for interpreting crack growth rate test results and a practical approach to predicting crack propagation under thermo-mechanical fatigue conditions based on readily available data is emphasised by many authors. In this study, a damage impact parameter was introduced to predict the crack growth rate and durability under isothermal and thermo-mechanical fatigue conditions. To validate the model, we used a single-edge notched specimen made of polycrystalline coarse-grained nickel-based alloy XH73M. The specimen was subjected to loading conditions that included in-phase and out-of-phase thermo-mechanical fatigue at a temperature range of 400–650 °C, as well as isothermal fatigue at 26 °C, 400 °C and 650 °C. A numerical analysis was used to simulate the material deformation behaviour at the crack tip according to a nonlinear kinematic hardening model. Numerical and experimental stress–strain state parameters based on strain energy density were used to formulate and estimate the damage impact parameter. Based on the correlation between the crack growth rate and the introduced damage impact parameter, a method for predicting crack propagation is proposed. The accuracy of the proposed method was experimentally validated. [ABSTRACT FROM AUTHOR]

This paper studies a time filtered finite element method for the unsteady inductionless magnetohydrodynamic (MHD) equations. The method uses the semi-implicit backward Euler scheme with a time filter in time and adopts the standard inf-sup stable fluid pairs to discretize the velocity and pressure, and the inf-sup stable face-volume elements for solving the current density and electric potential in space. Since the time filter for the velocity is added as a separate post-processing step, the scheme can be easily incorporated into the existing backward Euler code and improves the time accuracy from first order to second order. The unique solvability, unconditional energy stability, and charge conservativeness of the scheme are also proven. In terms of the energy arguments, we establish the error estimates for the velocity, current density, and electric potential. Numerical experiments are performed to verify the theoretical analysis. [ABSTRACT FROM AUTHOR]

Purpose: Finite element (FE) models have emerged as a powerful method to study biomechanical complexities of velopharyngeal (VP) function. However, existing models have overlooked the active contributions of the lateral pharyngeal wall (LPW) in VP closure. This study aimed to develop and validate a more comprehensive FE model of VP closure to include the superior pharyngeal constrictor (SPC) muscle within the LPW as an active component of VP closure. Method: The geometry of the velum and the lateral and posterior pharyngeal walls with biomechanical activation governed by the levator veli palatini (LVP) and SPC muscles were incorporated into an FE model of VP closure. Differing muscle activations were employed to identify the impact of anatomic contributions from the SPC muscle, LVP muscle, and/or velum for achieving VP closure. The model was validated against normative magnetic resonance imaging data at rest and during speech production. Results: A highly accurate and validated biomechanical model of VP function was developed. Differing combinations and activation of muscles within the LPW and velum provided insight into the relationship between muscle activation and closure patterns, with objective quantification of anatomic change necessary to achieve VP closure. Conclusions: This model is the first to include the anatomic properties and active contributions of the LPW and SPC muscle for achieving VP closure. Now validated, this method can be utilized to build robust, comprehensive models to understand VP dysfunction. This represents an important advancement in patient-specific modeling of VP function and provides a foundation to support development of computational tools to meet clinical demand. [ABSTRACT FROM AUTHOR]

This paper develops a mathematical framework that aims to control the temperature and rotational speed in the activation process of a gas turbine in an optimal way. These controls influence the deformation and the stress in the component due to centripetal loads and transient thermal stress. An optimal control problem is formulated as the minimization of maximal von Mises stress over a given time and over the whole component. To find a solution for this, we need to solve the linear thermoelasticity and the heat equations using the finite element method. The results for the optimal control as functions of the rotation speed and external gas temperature over time are computed by sequential quadratic programming, where gradients are computed using finite differences. The overall outcome reveals a significant reduction of approximately 10%, from $ 830\,\frac {{\rm N}}{{\rm mm}^2} $ 830 N mm 2 to $ 750\,\frac {{\rm N}}{{\rm mm}^2} $ 750 N mm 2 , in von Mises stress by controlling two parameters, along with the temporal separation of physical control phenomena. [ABSTRACT FROM AUTHOR]

Building acoustics simulation of a wooden frame wall Building physics simulations have already become firmly established in the everyday planning of hygrothermal conditions. In contrast, simulating real physical effects in building acoustics, especially in lightweight construction, to enable precise predictions is still a challenge. With the increasing demand in timber construction, both the requirements and the need for planning security are growing. Reliable frequency‐dependent prediction of the sound insulation of lightweight components could save resource‐consuming measurements. So far, the Finite Element Method (FEM) has proven to be a suitable method for conducting building acoustics parameter studies on lightweight components and evaluating constructive changes in relation to each other. This article presents the simulation of a timber frame wall in window size using the FEM. The simulation results, conducted with the software "COMSOL Multiphysics 6.1", are compared with building acoustic measurements. Using the simulation, the sound insulation is predicted with a maximum deviation of 5 dB per 1/3‐octave band. In FEM, the quality of the input data is crucial, with relevant stiffness values and loss factors of all materials determined through modal analyses. This approach becomes particularly relevant for multi‐layered anisotropic components. In addition to the validation, parameter variations were carried out based on the model. The results of these studies are also discussed in this work. [ABSTRACT FROM AUTHOR]

This article presents an experimental and numerical study of the collapse behavior of a 60‐m‐high cement silo structure under blast loading, analyzed using SAP2000 (FEM‐NDA) and LS‐DYNA (FEM‐NDA‐explicit code) models to simulate the collapse mechanism. Considering the seismic events in Kahramanmaras, Turkiye, on February 6, 2023, with magnitudes of 7.8 and 7.6, the necessity for the explosive demolition of hundreds of thousands of structures has underscored the urgency of rapid planning. This situation requires a particular focus on the expeditious analysis of demolition methodologies. The study includes pre‐planning stages, sudden column removals and the detonation of columns with blast loads for the controlled demolition of a full‐scale existing silo structure. To overturn the structure, the columns inside the wedge region were suddenly removed using SAP2000 nonlinear dynamic analysis (NDA) to understand the subsequent load redistribution. A study was conducted to compare the use of shell and plate elements in SAP2000 for a 1‐m‐thick wall silo. The results showed that using shell elements provided relatively closer results to real values than plate elements. For the explicit analysis part, the structural components were modeled as solid materials, and columns were detonated with blast loads. The models and actual demolition frame‐by‐frame results of the structure were compared, and the numerical model's accuracy was validated using experimental data from stationary cameras and drones, with the explicit analysis results found to be in agreement. While explicit analysis yielded results more in line with real data, SAP2000 NDA provided relatively distant results, although SAP2000‐NDA was more time‐efficient compared to explicit analysis models. However, a preliminary evaluation can be made if the characteristics of both programs are understood. The documented information on full‐scale structure demolition and findings presented in this paper will serve as a resource for future studies and provide a reference for researchers. [ABSTRACT FROM AUTHOR]

Polyurethane elastomer exhibits a complex behavior in response to external forces, which necessitates the use of specialized modeling methods that are often unavailable in standard analysis software. In response to this challenge, researchers have developed a new class in the OpenSees software that enables highly accurate modeling of polyurethane elastomer behavior using laboratory test data. The newly developed class has proven to be highly effective in validating the behavior of polyurethane elastomer, demonstrating that it offers high accuracy in modeling the material's behavior. The ability to accurately model the behavior of polyurethane elastomer is essential to ensure the safety and reliability of structures that incorporate this material. The findings of this research have significant implications for the design and analysis of structures incorporating polyurethane elastomer, offering new insights into its use as a smart material for enhancing structural performance under extreme loads. [ABSTRACT FROM AUTHOR]

In this study, 18 rib cages (8 males and 10 females) were segmented from computer tomography (CT) images. In order to analyze the potential differences in thoracic biomechanics during cardiopulmonary resuscitation (CPR), a set of numerical experiments was conducted using finite elements (FE). Compression forces were applied at different points on the rib cage. Results indicated that the optimal compression area for both sexes is the sternum at the 5th rib level, requiring the least force to achieve the desired compression depth. Males required greater force than females. Among females, those with lower width/depth ratios (more rounded thoracic shape) required less force compared to those with higher ratios (more oval‐shaped thorax). [ABSTRACT FROM AUTHOR]

Endovascular coil embolization is the primary therapeutic modality for intracranial aneurysms. Substantial reports have been found regarding the coil packing density and inflow jet. However, the hemodynamic effect of increasing the rate of tamponade in the inflow jet area within the aneurysm remains unclear. In this study, individualized geometries of six intracranial aneurysms were recruited: all six aneurysms were located in the internal carotid artery. Two groups were created by changing the position and orientation of the microcatheter for the release of the third segment of the filling coil. The finite element method was used to simulate coil deployment. Computational fluid dynamics was used to characterize hemodynamics in post‐deployment aneurysms. The parameters evaluated included velocity reduction, wall shear stress (WSS), low WSS (LWSS), relative residence time (RRT), flow kinetic energy in the neck region of the aneurysms, and residual flow volume (RFV) in the aneurysms. At the peak time (t = 0.17 s), the targeted deployment group has similar proportion of LWSS area to conventional deployment groups: targeted 78.13% ± 34.59% versus normal 74.20% ± 36.94% (mean ± SD, p = 0.583). The targeted deployment group has a higher RRT area (targeted 16.84% ± 5.58% vs. normal 6.42% ± 5.67% [mean ± SD, p = 0.009]), smaller flow kinetic energy (targeted 9.43 ± 4.33 vs. normal 16.23 ± 5.92 [mean ± SD, p = 0.047]), and a larger RFV in the aneurysms (targeted 35.97 ± 24.35 mm3 vs. normal 25.80 ± 18.94 mm3 [mean ± SD, p = 0.44]). Inflow jets play an important role in the treatment of aneurysms, and deploying filling coils in accordance with inflow jets may result in a better hemodynamic environment. [ABSTRACT FROM AUTHOR]

Positioning mechanisms are critical components in advanced optical systems, such as Earth observation telescopes. They are used to adjust the position of one or more optical elements to account for various factors, including thermal effects, settling due to launch or environmental loads, thermo-elastic deformations, or the need to compensate for spacecraft microvibrations or jitter. In this context, the paper presents the design, implementation, and testing of a tip/tilt positioning mechanism. The paper describes in detail the various components of the mechanism, which is driven by four multilayer piezoelectric actuators, each preloaded by a compliant mechanical amplifier. It then presents the finite element model that simulates the mechanical behavior of the mechanism, and the series of tests carried out on the prototype. The primary objective of this mechanism is to enable and control the precise movement of an optical payload in three degrees of freedom: a translation along its optical axis and two rotations about axes located on its optical surface. • A Fine Steering Mechanism driven by four preloaded piezoelectric actuators. • A mechanism withstanding environmental loads typical for EO optical payloads. • A robust and high performing mechanism for precise optical payload manipulation. [ABSTRACT FROM AUTHOR]

Hot rolling processes have been extensively used to produce round bars by reducing the cross‐sectional area of continuously cast steel. The current trend toward increasing productivity often requires a more aggressive reduction per pass. Establishing safe and optimized hot rolling parameters must be determined to avoid damage while deforming the specific steel composition. Understanding the damage mechanism during the metal forming process is vital for product quality. Herein, a combined experimental and simulation approach is developed to track the evolution potential damage during hot bar rolling. Hot tension tests are conducted on as‐cast vanadium microalloyed 15V38 steel at different hot rolling temperatures and strain rate conditions to develop Johnson–Cook‐type material model. A thermomechanical finite element model is developed to simulate potential damage trends in a 12‐pass square‐to‐round and 8‐pass round‐to‐round standard industrial hot rolling process, employing damage criteria. Results are illustrated by creating a damage map at each rolling pass to determine the critical hot rolling conditions for damage initiation. Several parametric studies are also performed to illustrate the application of the suggested methodology for hot rolling process optimization. Results show that the probability of the damage initiation is higher at higher pass reductions and lower temperatures. [ABSTRACT FROM AUTHOR]

ABSTRACT An approach to the analysis of the influence of impact loading on creep, accumulation of hidden damage and fracture of structural elements made of functionally graded materials (FGM) is proposed. The approach is based on the analysis of additional damage caused by the impact loading and the stress redistribution caused by it. For the numerical modeling, finite element analysis was applied using algorithms for determining the size and direction of motion of macroscopic defects by means of the analysis of the time‐varying damage field. The fracture after an impact on a beam made from FGM is considered. The nature of fracture of a beam made of two‐layer metal‐ceramic material was studied. The advantages of using FGM to ensure a better long‐term response of a structural element to a non‐destructive impact loading are shown. An approach to determine the time until the complete fracture of the FGM beam by the simultaneous description of the motion of two cracks is proposed. [ABSTRACT FROM AUTHOR]

Advances in modal analysis have motivated finite element model updating for damage identification based on vibration monitoring. However, the model updating problem is usually ill-posed owing to limited and noisy measurement data, and the predominant sensitivity-based optimization approaches may suffer from large linearization errors. To address these challenges, this article proposes using the unscented Kalman inversion with $ {l_1} $ l 1 -norm regularization (UKI- $ {l_1} $ l 1 ) to solve the damage identification problem in a derivative-free manner. UKI- $ {l_1} $ l 1 implements an explicit transformation converting the $ {l_1} $ l 1 -norm regularized least-squares problem into the $ {l_2} $ l 2 -norm regularized problem, which can be readily solved by the UKI with measurement augmentation. The effectiveness of the proposed approach is evaluated through identifying damage of a continuous beam structure and a reinforced concrete frame structure. Numerical investigation confirms the robustness of UKI- $ {l_1} $ l 1 to measurement noise, and experimental study demonstrates that the damage identification results obtained by UKI- $ {l_1} $ l 1 match well with expectations. [ABSTRACT FROM AUTHOR]

G-Lattices—a novel family of periodic lattice structures introduced by Arash Armanfar and Erkan Gunpinar—demonstrate diverse mechanical properties owing to their generatively designed shapes. To assess the properties of lattice structures effectively, experimental tests and finite element analysis (FEA) are commonly used. However, the complex nature of these structures poses challenges, leading to high computation time and costs. This study proposes a machine learning (ML) approach to predict the mechanical properties of G-Lattices quickly under defined loading conditions. G-Lattice training data is generated through a sampling technique, and voxelized data is employed as ML feature vectors for predicting properties determined by FEA. To address the uneven distribution of target values, samples are clustered and utilized to train a classification model. This two-step process involves the classification of G-Lattices, followed by the application of specific regression models trained for each cluster for precise predictions. According to experiments, the ML model obtained, which predicts stiffness-over-volume ratios for G-Lattices, achieved a mean absolute percentage error of 6.5% for 1600 G-Lattices in a few seconds. Furthermore, approximately 70% of the 40,000 G-Lattices exhibited errors within 5%. The ML model's rapid predictions and acceptable accuracy make it useful for quick decision-making and seamless integration into optimization processes. [ABSTRACT FROM AUTHOR]

Piezoresistive sensors are indispensable in applications such as healthcare monitoring, artificial intelligence, and advanced communication systems. However, achieving wearable sensors that offer both high sensitivity and a wide linear range remains a significant challenge. Here, an all‐carbon piezoresistive sensor is presented, named, featuring high biocompatibility, chemical stability, environmental sustainability, and a straightforward fabrication process. This sensor, integrating a double‐sided pyramidal carbon aerogel (DPA) as the sensing layer, a silicone frame as the elastic support (ES), and superhydrophobic graphene‐coated nylon fabric as the breathable conductive substrate (BCS), was named as DPA‐ES@BCS. Finite element analysis confirms that the synergistic interaction between the DPA and silicone frame enhances the sensor's sensitivity while extending its linear range. This multiscale design achieves an exceptional sensitivity of 37.3 kPa−1, a broad linear detection ranges from 0 to 1.4 MPa, and outstanding stability over 30 000 cycles. Additionally, the high‐performance wearable sensor is well‐suited for real‐time physiological signal monitoring and demonstrates exceptional capability in voice recognition, accurately distinguishing words using machine learning algorithms. Moreover, the DPA‐ES@BCS sensor array shows great potential for enhancing information security through dual‐factor authentication. This approach not only advances the piezoresistive performance of all‐carbon sensors but also provides a strong foundation for developing next‐generation sensor technologies. [ABSTRACT FROM AUTHOR]

The current article is an innovative attempt to utilize the full layerwise (LW) finite element approach for investigating the nonlinear vibrations of sandwich plates with functionally graded graphene nanoplatelets (GPLs)-reinforced face sheets. The fundamental novelty of this research is the employment of the full LW theory, which provides accuracy equivalent to three-dimensional (3D) elasticity while reducing computational cost, simplifying mesh modification, and enabling faster attainment of the element stiffness matrix by maintaining the 2D structure. The uniform or functionally graded distributions of GPLs within the face sheets are considered. The effective material properties of face sheets are estimated according to the rule of mixtures and the Halpin–Tsai model. Subsequent to confirming the convergence and validity of the numerical approach and formulation, thorough parametric analyses are executed to assess the effects of various factors involving the thickness ratio of the core-to-face sheet, edge constraints, and geometric parameters, together with dispersion pattern, volume fraction, and the dimension of GPLs on the nonlinear vibration conducts of the sandwich plate. The findings demonstrate that as the core-to-face sheet thickness ratio of the sandwich plate rises, the linear and nonlinear-to-linear frequency (NTL) display opposite trends. Furthermore, the NTL ratio is not notably altered by the configuration type of the face sheets. [ABSTRACT FROM AUTHOR]

Planar phased array antennas have significant applications in fields such as space communication, electronic reconnaissance, navigation, remote sensing and deep space exploration. This study focuses on the active vibration control of a novel on-orbit assembled large-scale two-dimensional planar phased array antenna. The novel structure and assembly method of the antenna are introduced. Using the finite element method, we develop the dynamic model of antenna structure. Due to the low and dense natural frequency characteristics of the structure, the distributed cable actuators are used to suppress the vibration. Considering the unilateral and saturated constraints of the cable force, the control law is designed by combining the linear quadratic regulator with the Bang–Bang regulator. The controllability criterion and particle swarm optimization algorithm are adopted to optimize the actuator distribution. We validate established dynamic model and control method by numerically simulating. The simulation results indicate that the dynamic model can describe the dynamic behavior as accurately as ABAQUS; the controller can effectively suppress the vibration of the antenna structure. [ABSTRACT FROM AUTHOR]

The nonlinear bending and vibration behaviors of a variable-width piezoelectric nanoplate considering flexoelectric effect are investigated in this paper. The nonlinear Mindlin plate theory and finite element method are applied to derive the governing equations of variable-width piezoelectric nanoplate with flexoelectricity. The influences of geometric nonlinearity, flexoelectricity, and varying width on the bending deflection and natural frequency of the piezoelectric nanoplate with flexoelectricity under four kinds of boundary conditions are explored in detail. The numerical results show that the flexoelectric effect can strongly influence the maximum deflection, the morphology of deformation, and the natural frequency of the variable-width piezoelectric nanoplate. The consideration of geometric nonlinearity becomes necessary for nanoplate exhibiting strong flexoelectricity or subject to significant voltage loads. The boundary conditions not only affect the morphology of deformation but also influence the variation trend of natural frequency with the variable-width ratio of the piezoelectric nanoplate. While the variation trend of maximum deflection is jointly affected by the boundary conditions and flexoelectricity. The closer the shape of the piezoelectric nanoplate is to a triangle, the greater the combined effect of boundary conditions and flexoelectricity on the variation trend of maximum deflection. The results of this study can contribute to the optimization of piezoelectric nanostructures, and they are helpful in enhancing our comprehension of the mechanical behavior of piezoelectric nanostructures. [ABSTRACT FROM AUTHOR]

In this work, the differential quadrature element method (DQEM) is used to conduct heat transfer and thermoelastic analysis for layered beams based on the two-dimensional Fourier's law and thermoelasticity theory. The method accounts for temperature-dependent (TD) material properties, nonuniform thermal boundary conditions, and various end constraints. To implement the method, the layered beam is decomposed into several sub-domains. At the interfaces of arbitrary two adjacent sub-domains, the continuity conditions are exactly enforced. The differential quadrature technique is applied for the spatial discretization of the governing equations together with the interface and boundary conditions. The convergence of the DQEM solutions is checked. The correctness of the DQEM solutions is validated by comparison with those obtained by the finite element method and those existing in the literature. Finally, the effects of various factors such as TD material properties, nonuniform thermal boundary conditions, and end constraints on the heat transfer and thermoelastic behaviors of the beam are studied. [ABSTRACT FROM AUTHOR]

The uncertainty in constitutive parameters significantly affects structural responses. This study examines the impact of these parameters on the damage to rectangular welded plates under multiple impacts using deep learning methods. A validated finite element model was used to generate a dataset by varying the constitutive parameters. Several surrogate models based on the Johnson–Cook models were compared for prediction accuracy. An attention-based neural network was applied for global sensitivity analysis of multiple-impact damage. The results indicate that models with attention mechanisms provide superior accuracy and efficiency for the damage of plate under repeated blast loading. Moreover, material parameters like density and yield strength are more influential under single impacts, while damage parameters become critical under repeated impacts. These findings offer insights for optimizing the safety of rectangular welded plates under varying impact conditions. [ABSTRACT FROM AUTHOR]

This paper presents a multi-dimensional variable-kinematics finite element model for nonlinear static analyses of structures with complex geometries. The approach incorporates higher-order beam models and classical solid finite elements in a unified framework, enabling refined modeling of complex geometries. The finite element procedure proposed follows the Carrera Unified Formulation (CUF) and uses a pure displacement-based methodology. The governing equations are derived within the classical continuum mechanics framework, and weak-form equilibrium equations are established using the Principle of Virtual Displacements (PVD). Within the CUF framework, higher-order beam and hexahedral solid models are defined in a unified manner, and the governing equations are written in terms of invariants of mathematical models used and the theory of structures approximation. A coupling technique is used between the beam and solid elements at the nodal level using superposition. The capabilities of fully nonlinear variable-kinematics models are investigated for the static analysis of various rectangular and curved structures. The numerical results are compared with solutions obtained using commercial software. Finally, the proposed methodology is applied to analyze more complex geometries in engineering applications. The results show the capabilities of variable-kinematics models in terms of both accuracy and computational efficiency for the computation of highly nonlinear deformed states and localized phenomena, such as stress concentrations and buckling. [ABSTRACT FROM AUTHOR]

The application of piezoelectric actuators in smart structures is a rapidly developing field, particularly in aerospace environments. Given the significant impact of thermal effects in aerospace applications, the study of thermopiezoelectricity has gained attention. This phenomenon accounts for the thermal field in addition to the mechanical and electrical fields. Consequently, coupling phenomena among these three fields, including pyroelectric and electrocaloric effects, must be considered. This paper examines how these coupling effects influence the performance of piezoelectric bender actuators in normal operation and under varying external environments. This analysis is conducted through a custom-written finite element code which takes the three fully coupled field equations of thermopiezoelectricity into account. Then, the temperature dependence of the piezoelectric strain coefficients is included into the developed code in a numerically efficient manner using a pre-computation approach. The effect of temperature-dependent material properties is investigated via a case study of a stratospheric balloon flight where the actuator is used as a lens positioning element and subjected to significant temperature variations. [ABSTRACT FROM AUTHOR]

We present a model-based feedforward control strategy suitable for designing swift rest-to-rest maneuvers for liquids in arbitrarily shaped containers. We employ the commonly used equivalent pendulum model to represent the sloshing dynamics and suggest a novel parameter identification scheme suitable for arbitrary container shapes and any number of sloshing modes. By computing natural modes and fluid reaction forces and torques for imposed harmonic container motions via a finite element model, we obtain data for the identification scheme. A fitting procedure then yields highly accurate parameters for a physical pendulum model, where each pendulum represents one sloshing mode. We also provide a thorough analysis of parameter identifiability and guidelines for obtaining robust parameter estimates. The proposed feedforward control method uses a virtual tray pendulum on which we place the container (in the form of its equivalent pendulum model). Designing the virtual tray such that the fluid's dominant sloshing mode cannot be excited by horizontally moving the tray pendulum pivot effectively zeros out any sloshing motion in this mode. We then exploit the flatness property of the resulting system to design rest-to-rest maneuvers where any residual sloshing motion (in higher modes) can be exactly stopped at the end of the maneuver. The effectiveness of the proposed method is demonstrated through extensive simulations and experimental results using a Martini cocktail glass, whose shape is challenging in terms of sloshing. The experimental results show the successful, accurate suppression of sloshing, validating the efficacy of the proposed concept. [ABSTRACT FROM AUTHOR]

Mechanical connection is a common method used for joining composite materials, but it is bound to open holes in the composite material structure. These open holes may cause stress concentration at the hole edge, impacting the overall mechanical properties of the component. In this paper, a machine learning-based method for predicting the mechanical properties of open-hole composite laminates is proposed based on generalized regression neural network. In detail, by using the Hashin failure criterion, the finite element models of composite laminates with single holes of different diameters have been established. Their load–displacement curves, maximum failure stresses and maximum failure strains are calculated numerically. Then, the different hole diameters and corresponding load–displacements can be used as the input and output variables of the generalized regression neural network to train the neural network model. Based on the optimal generalized regression neural network model, the mechanical properties of the composite laminates with a certain single hole diameter can be predicted. Compared with the uniaxial tensile experiment of open-hole composite laminates, the effectiveness of this machine learning method is verified. Furthermore, the changes in mechanical properties of double-hole composite laminates under different hole diameters and positions are analyzed. This study holds significant practical implications for enhancing the understanding of the mechanical properties of composite materials and the influence of defects on their performance. [ABSTRACT FROM AUTHOR]

This work is concerned with the interpolation of a function f when using a low number of interpolation points, as required by the finite element method for solving PDEs numerically. The function f is assumed to have a jump or a steep derivative, and our goal is to minimize the oscillations produced by the Gibbs phenomenon while preserving the approximation properties for smoother functions. This is achieved by interpolating the transform f ^ = g ∘ f using Lagrange polynomials, where g is a rational transformation chosen by minimizing a suitable functional depending on the values of f . The mapping g is monotonic and constructed to possess boundary layers that remove the Gibbs phenomenon. No previous knowledge of the location of the jump is required. The extension to functions of several variables is straightforward, of which we provide several examples. Finally, we show how the interpolation fits the finite element method and compare it with known strategies. [ABSTRACT FROM AUTHOR]

The effectiveness of multiscale modeling, consisting of quantum chemical reaction path calculations, molecular dynamics simulations, and microscopic and macroscopic finite element analysis, developed for the process-induced residual deformation of carbon fiber-reinforced plastic was experimentally evaluated. In this study, non-crimp fabric composites with an arbitrary thermoset resin were fabricated, and process-induced deformation was measured. Process-induced residual deformations due to cure shrinkage and thermal shrinkage of cross-ply laminates under conditions similar to those in the experiment were predicted using multiscale modeling. The predicted deformation shape and maximum deformation value are in good agreement with the fabrication experiments. Multiscale modeling can consider the combined factors that affect the deformation (i.e. size, elastic moduli, coefficient of thermal expansion, and fiber volume fraction) and can provide important knowledge regarding the development of high-performance composite structures and for stable manufacturing. [ABSTRACT FROM AUTHOR]

Access cavity preparation represents the initial step in root canal treatment. Minimally invasive approaches have gained increasing attention and involve advancements in the traditional access cavity preparation. Simultaneously, the development of three‐dimensional finite element analysis (3D‐FEA) has provided a theoretical foundation for evaluating the merits and drawbacks of various access cavity preparations. Studies using static loading 3D‐FEA have suggested that conservative access cavity preparation reduces the concentration of stress in the cervical region, thereby strengthening fracture resistance. However, the lack of support from clinical data raises concerns about the validity of this suggestion. Conversely, studies involving cyclic loading 3D‐FEA and dynamic loading 3D‐FEA have challenged the prevailing perspectives by taking into account additional factors such as filling materials, thus providing a more comprehensive understanding of the impact of access cavity preparation on fracture resistance. Existing research lacks a comprehensive comparison of the different 3D‐FEA methods, and this review fills this gap by providing a systematic assessment of different 3D‐FEA methods and their applications in access cavity preparation. [ABSTRACT FROM AUTHOR]

Deep Anterior Lamellar Keratoplasty (DALK) is a surgical procedure used to restore sight and manage corneal diseases by replacing cloudy corneal tissue with allogeneic normal corneal tissue or artificial corneal material. However, the limited availability and mechanical defects of artificial corneal materials pose challenges in DALK. To predicting postoperative mechanical behavior of Deep Anterior Lamellar Keratoplasty (DALK), a three-dimensional finite element model of the postoperative DALK cornea with suture holes was developed. The postoperative corneal displacement and von Mises (VM) stress changes were also simulated under varying depths of cut (DOC: 0.16-0.26 μm), intraocular pressure (IOP: 12, 15, 18 mmHg), and central corneal thickness (CCT: 420-620 μm). The model indicated that higher IOP and CCT were associated with improved postoperative corneal stability. The postoperative corneal displacement increased from the edge to the center, while the maximum VM stress value occurs at the corneal suture hole. Corneal displacement and VM stress decrease with increasing CCT and decreasing IOP. DOC has a slight effect on corneal displacement and VM stress, with an overall positive relationship. The model has potential application in the preoperative assessment of risk in keratoplasty. [ABSTRACT FROM AUTHOR]

This paper presents a novel computational framework for neural-driven finite element muscle models, with an application to amyotrophic lateral sclerosis (ALS). The multiscale neuromusculoskeletal (NMS) model incorporates physiologically accurate motor neurons, 3D muscle geometry, and muscle fiber recruitment. It successfully predicts healthy muscle force and tendon elongation and demonstrates a progressive decline in muscle force due to ALS, dropping from 203 N (healthy) to 155 N (120 days after ALS onset). This approach represents a preliminary step towards developing integrated neural and musculoskeletal simulations to enhance our understanding of neurodegenerative and neurodevelopmental conditions through predictive NMS models. [ABSTRACT FROM AUTHOR]

The increasing prevalence of adult spinal deformity requires long spino-pelvic instrumentation, but pelvic fixation faces challenges due to distal forces and reduced bone quality. Bi-planar multi-energy X-rays (BMEX) were used to develop a patient-specific finite element model (FEM) for evaluating pelvic fixation. Calibration involved 10 patients, and an 81-year-old female test case was used for FEM customization and pullout simulation validation. Calibration yielded a root mean square error of 74.7 mg/cm3 for HU. The simulation accurately replicated the experimental pullout test with a force of 565 N, highlighting the method's potential for optimizing biomechanical performance for pelvic fixation. [ABSTRACT FROM AUTHOR]

The article aims to design and develop a topology-optimized endosseous cuspid tooth implant of the maxilla region. The manuscript presents a numerical analysis of the resulting von Mises stresses and effective strain resulting in the topology-optimized implant with occlusal loading of 110 N. Solid Isotropic Material with Penalization (SIMP) method is employed for topology optimization and four different models, namely model-1, model-2, model-3, and model-4, are developed based on volume reduction rates of 8%, 16%, 24%, and 32%, respectively. FEA results highlight that the maximum stress and strain in the screw increases with volume reduction rates. The comparative analyses of the resulting stresses in the compact and cancellous bone along with the strain in the screw led to the conclusion that model-1, model-2, and model-3 resulted in moderate stresses on compact and cancellous bone compared to the original model of the implant. However, the screw and bones are subjected to maximum stress and strain in the model-4. The study concludes that model-2, with 16% reduced volume and 14.2% reduced mass as compared to the original implant, may be considered as the optimized design of the model. The resulting model offers a significant reduction in the weight and volume with a minor increase in effective stress and strain without negatively impacting the functionality and bio-mechanical performance of the implant. The optimized dental implant prototype is also fabricated as a proof of concept by the Fused Deposition Modelling process. [ABSTRACT FROM AUTHOR]