首页期刊导航|Computer methods in applied mechanics and engineering
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Computer methods in applied mechanics and engineering
North-Holland Pub. Co.
Computer methods in applied mechanics and engineering

North-Holland Pub. Co.

周刊

0045-7825

Computer methods in applied mechanics and engineering/Journal Computer methods in applied mechanics and engineeringSCIISTP
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    Neurodevelopmental disorders modeling using isogeometric analysis, dynamic domain expansion and local refinement

    Qian K.Liao A.S.Webster-Wood V.A.Zhang Y.J....
    1.1-1.20页
    查看更多>>摘要:© 2024 The AuthorsNeurodevelopmental disorders (NDDs) have arisen as one of the most prevailing chronic diseases within the US。 Often associated with severe adverse impacts on the formation of vital central and peripheral nervous systems during the neurodevelopmental process, NDDs are comprised of a broad spectrum of disorders, such as autism spectrum disorder, attention deficit hyperactivity disorder, and epilepsy, characterized by progressive and pervasive detriments to cognitive, speech, memory, motor, and other neurological functions in patients。 However, the heterogeneous nature of NDDs poses a significant roadblock to identifying the exact pathogenesis, impeding accurate diagnosis and the development of targeted treatment planning。 A computational NDDs model holds immense potential in enhancing our understanding of the multifaceted factors involved and could assist in identifying the root causes to expedite treatment development。 To tackle this challenge, we introduce optimal neurotrophin concentration to the driving force and degradation of neurotrophin to the synaptogenesis process of a 2D phase field neuron growth model using isogeometric analysis to simulate neurite retraction and atrophy。 The optimal neurotrophin concentration effectively captures the inverse relationship between neurotrophin levels and neuron survival, while its degradation regulates concentration levels。 Leveraging dynamic domain expansion, the model efficiently expands the domain based on outgrowth patterns to minimize degrees of freedom。 Based on truncated T-splines, our model simulates the evolving process of complex neurite structures by applying local refinement adaptively to the cell/neurite boundary。 Furthermore, a thorough parameter investigation is conducted with detailed comparisons against neuron cell cultures in experiments, enhancing our fundamental understanding of the possible mechanisms underlying NDDs。

    Fatigue-constrained topology optimization method for orthotropic materials based on an expanded Tsai-Hill criterion

    Ye H.Xiao Y.Dong Y.Xie J....
    1.1-1.21页
    查看更多>>摘要:© 2024 Elsevier B。V。Fatigue-constrained topology optimization (FCTO) is a currently research hotspot, and its fatigue constraints have material property dependency, highly nonlinear, and local features, which lead to challenges for the algorithm stability, computational efficiency, and different material application of FCTO。 This research provides a FCTO method for structures subjected to variable-amplitude fatigue loading, incorporating the potential orthotropic behavior of materials。 Firstly, a fatigue failure function derived from the constitutive model of orthotropic materials and the polynomial form in the Tsai-Hill criterion is proposed to predict multiaxial fatigue failure with a given loading spectrum。 Secondly, a FCTO model minimizing structural weight is established based on the independent continuous mapping (ICM) method and constrained by a filtered, scaled, and aggregated fatigue failure function to enhance stability and convergence speed。 Thirdly, the sensitivities of objective and constraint in the FCTO model are analyzed, and the optimal model is solved using convolutional filters and the globally convergent method of moving asymptotes (GCMMA) to generate manufacturable design。 Finally, numerical examples demonstrate the feasibility of the method for 2D and 3D structures with varying material properties, load spectrums, and design domains。 The developed method aims to facilitate the creation of lightweight designs capable of withstanding fatigue loads and to provide a framework and references for the advancement of integrated material-structure-performance designs。

    Isogeometric topology optimization (ITO) of fiber reinforced composite structures considering stress constraint and load uncertainties

    Cheng J.Tan J.Fu H.Liu Z....
    1.1-1.26页
    查看更多>>摘要:© 2024 Elsevier B。V。A novel Isogeometric topology optimization (ITO) method considering stress constraint and load uncertainties is proposed for the fiber reinforced composite structures。 Firstly, with the density and fiber orientations at the control points of Non-Uniform Rational B-Splines (NURBS) defined as design variables while the magnitudes and direction angles of uncertain external loads described as interval variables, the ITO model for the fiber reinforced composite structures is constructed to minimize the structural compliance under the constraints on both material usage and global failure coefficient。 To accurately calculate the material properties and stress distribution within fiber reinforced composite structures, the Gauss subdivision and the Tsai-Hill criterion combined with the P-norm function are introduced。 Further, the critical loads leading to the worst structural performance are determined based on the weighted Sigmoid penalty of the stress constraint for balancing the performance requirements of high stiffness and high strength。 Finally, the ITO model is solved by integrating all the proposed innovations with the Method of Moving Asymptotes (MMA)。 The validity and effectiveness of the proposed ITO method are validated by both numerical and engineering examples。

    Adaptive parameter selection in nudging based data assimilation

    Cibik A.Fang R.Layton W.Siddiqua F....
    1.1-1.16页
    查看更多>>摘要:© 2024 Elsevier B。V。Data assimilation combines (imperfect) knowledge of a flow's physical laws with (noisy, time-lagged, and otherwise imperfect) observations to produce a more accurate prediction of flow statistics。 Assimilation by nudging (from 1964), while non-optimal, is easy to implement and its analysis is clear and well-established。 Nudging's uniform in time accuracy has even been established under conditions on the nudging parameter χ and the density of observational locations, H, Larios et al。 (2019)。 One remaining issue is that nudging requires the user to select a key parameter。 The conditions required for this parameter, derived through á priori (worst case) analysis are severe (Section 2。1 herein) and far beyond those found to be effective in computational experience。 One resolution, developed herein, is self-adaptive parameter selection。 This report develops, analyzes, tests, and compares two methods of self-adaptation of nudging parameters。 One combines analysis and response to local flow behavior。 The other is based only on response to flow behavior。 The comparison finds both are easily implemented and yields effective values of the nudging parameter much smaller than those of á priori analysis。

    A multi-level adaptive mesh refinement strategy for unified phase field fracture modeling using unstructured conformal simplices

    Pandey A.Kumar S.
    1.1-1.33页
    查看更多>>摘要:© 2024 Elsevier B。V。The phase field model (PFM) has emerged as a popular computational framework for analyzing and simulating complex fracture problems。 Despite PFM's inherent capacity to model relatively complex fracture phenomena such as nucleation, branching, deflection, etc。, the computational costs involved in the analysis are quite high。 Hence, a multi-level adaptive mesh refinement framework is proposed for a unified phase field model (PFCZM) to improve the computational efficiency。 The proposed adaptive framework can be implemented for structured as well as unstructured meshes, making it suitable for analyzing complex fracture problems。 This framework adaptively generates local mesh refinement at the discrete crack tip, based on an active element error indicator, until the damage is initiated, hence completely avoiding the pre-requisite of local mesh refinement。 Further, the gradient of energy degradation and the gradient of dissipated fracture energy based error indicators are proposed to capture the fracture domain and regions ahead of the crack tip, respectively。 The Newest vertex and Maubach's refinement routines are implemented as the element level-based hierarchical refinement strategies。 Unlike recently proposed adaptive strategies for PFCZM involving elements with hanging nodes, the proposed adaptive framework inherently addresses the conformity and reflectivity of the discretized domain efficiently。 The robustness and accuracy of the framework is checked against four benchmark fracture problems, demonstrating a significant reduction in computational costs with sufficient accuracy。

    Spherical harmonics-based pseudo-spectral method for quantitative analysis of symmetry breaking in wrinkling of shells with soft cores

    Zavodnik J.Brojan M.
    1.1-1.19页
    查看更多>>摘要:© 2024 The AuthorsA complete understanding of the wrinkling of compressed films on curved substrates remains illusive due to the limitations of both analytical and current numerical methods。 The difficulties arise from the fact that the energetically minimal distribution of deformation localizations is primarily influenced by the inherent nonlinearities and that the deformation patterns on curved surfaces are additionally constrained by the topology。 The combination of two factors – the need for dense meshes to mitigate the topological limitations of discretization in domains such as spheres where there is no spherically-symmetric discretizations, and the intensive search for minima in a highly non-convex energy landscape due to nonlinearity – makes existing numerical methods computationally impractical without oversimplifying assumptions to reduce computational costs or introducing artificial parameters to ensure numerical stability。 To solve these issues, we have developed a novel (less) reduced version of shell theory for shells subjected to membrane loads, such as during wrinkling。 It incorporates the linear contributions of the usually excluded tangential displacements in the membrane strain energy and thus retains the computational efficiency of reduced state-of-the-art methods while nearly achieving the accuracy of the full Kirchhoff–Love shell theory。 We introduce a Galerkin-type pseudo-spectral method to further reduce computational costs, prevent non-physical deformation distribution due to mesh-induced nucleation points, and avoid singularities at the poles of the sphere。 The method uses spherical harmonic functions to represent functions on the surface of a sphere and is integrated into the framework of minimizing the total potential energy subject to constraints。 This robust approach effectively solves the resulting non-convex potential energy problem。 Our method accurately predicts the transition between deformation modes based solely on the material and geometric parameters determined in our experiments, without the need to introduce artificial parameters for numerical stability and/or additional fitting of the experimental data。

    A novel Hybrid Particle Element Method (HPEM) for large deformation analysis in solid mechanics

    Fang H.Yin Z.-Y.
    1.1-1.23页
    查看更多>>摘要:© 2024 Elsevier B。V。This paper develops a novel Hybrid Particle Element Method (HPEM) to model large deformation problems in solid mechanics, combining the strengths of both mesh-based and particle approaches。 In the proposed method, the computational domain is discretized into two independent components: a set of finite elements and a set of particles。 The finite elements serve as a temporary tool to compute the spatial derivatives of field variables, while the particles are used for storing history variables and establishing equilibrium equations。 Spatial derivatives of field variables on particles are obtained by averaging the surrounding Gauss points of finite elements with a smoothing function。 When the finite element mesh becomes distorted, it can be arbitrarily adjusted or completely regenerated。 No global variable mapping is required when mesh adjustment or regeneration is performed, thus avoiding irreversible interpolation errors。 The proposed method is validated through six typical examples, assessing its accuracy, efficiency, and robustness。 The superior performance of the proposed method is comprehensively demonstrated through comparisons with several existing numerical methods。

    A physical-information-flow-constrained temporal graph neural network-based simulator for granular materials

    Zhao S.Chen H.Zhao J.
    1.1-1.25页
    查看更多>>摘要:© 2024 Elsevier B。V。This paper introduces the Temporal Graph Neural Network-based Simulator (TGNNS), a novel physical-information-flow-constrained deep learning-based simulator for granular material modeling。 The TGNNS leverages a series of frames, each representing material point positions, enabling particle dynamics to propagate through the sequence, resulting in a more physically grounded architecture for granular flow learning。 The TGNNS has been thoroughly trained, validated, and tested using simulation data derived from a hierarchical multiscale modeling approach, DEMPM, which combines the Material Point Method (MPM) and the Discrete Element Method (DEM)。 Results demonstrate that the TGNNS performs robustly with previously unseen datasets of varying granular column sizes, even under manually incorporated barrier boundary conditions。 Remarkably, the TGNNS operates at a speed 100 times faster than direct numerical simulation using the state-of-the-art GPU-based DEMPM。 Employing a unique deep learning architecture that is constrained by the flow of physical information, the TGNNS offers a pioneering learning paradigm for multiscale emerging behaviors of granular materials and provides a potential solution to physics-based modeling in digital twins involving granular materials。

    Kolmogorov-Arnold-Informed neural network: A physics-informed deep learning framework for solving forward and inverse problems based on Kolmogorov-Arnold Networks

    Wang, YizhengSun, JiaBai, JinshuaiAnitescu, Cosmin...
    1.1-1.37页
    查看更多>>摘要:AI for partial differential equations (PDEs) has garnered significant attention, particularly with the emergence of Physics-informed neural networks (PINNs)。 The recent advent of Kolmogorov- Arnold Network (KAN) indicates that there is potential to revisit and enhance the previously MLP-based PINNs。 Compared to MLPs, KANs offer interpretability and require fewer parameters。 PDEs can be described in various forms, such as strong form, energy form, and inverse form。 While mathematically equivalent, these forms are not computationally equivalent, making the exploration of different PDE formulations significant in computational physics。 Thus, we propose different PDE forms based on KAN instead of MLP, termed Kolmogorov-Arnold-Informed Neural Network (KINN) for solving forward and inverse problems。 We systematically compare MLP and KAN in various numerical examples of PDEs, including multi-scale, singularity, stress concentration, nonlinear hyperelasticity, heterogeneous, and complex geometry problems。 Our results demonstrate that KINN significantly outperforms MLP regarding accuracy and convergence speed for numerous PDEs in computational solid mechanics, except for the complex geometry problem。 This highlights KINN's potential for more efficient and accurate PDE solutions in AI for PDEs。

    Modelling high temperature progressive failure in C/SiC composites using a phase field model: Oxidation rate controlled process

    Hu X.Tan S.Sun Z.Wang T....
    1.1-1.26页
    查看更多>>摘要:© 2024 Elsevier B。V。High-temperature oxidation damage in C/SiC composite, alongside mechanical failure, has becoming a focal point of developing high performance motor components。 However, most of existing models focus on only one field and thus can hardly to simulate a complete process。 To address this, a thermodynamically consistent phase field model tailored specifically for C/SiC composites is proposed。 This model offers a long-desired capability to encompass both carbon fiber oxidation in oxidation controlled stage and mechanical fracture, as well as their intricate interactions。 Instead of relying on predefined fields or empirical knowledge, our model determines the oxygen field distribution and the evolution of new cracks through the differential equations rigorously, thereby providing a more accurate estimation of the location and extent of the failure process。 The validity and reliability of our model have been tested through a few numerical studies。 The proposed model has successfully captured the intricate characteristics of micro-crack propagation in C/SiC composites, including the saturation of cracks originating from the SiC matrix and the fracture process of carbon fibers after oxidation。 As a result, our research is anticipated to be serving as an invaluable foundation for quantitative investigations into the performance of C/SiC composites, paving the way for the development of more robust and reliable high-temperature C/SiC composites。