Computer Methods in Applied Mechanics and Engineering最新文献

{"title":"Modelling of thermo-mechanical coupling effects in rock masses using an enriched nodal-based continuous-discontinuous deformation analysis method","authors":"Yang Xia ,&nbsp;Yongtao Yang ,&nbsp;Hong Zheng ,&nbsp;Shuilin Wang","doi":"10.1016/j.cma.2024.117543","DOIUrl":"10.1016/j.cma.2024.117543","url":null,"abstract":"<div><div>In this paper, the nodal-based continuous-discontinuous deformation analysis method (NCDDAM) is enriched to simulate the thermo-mechanical coupling effects in rock masses. A distance-based contact potential algorithm is first incorporated into NCDDAM to avoid the dependency of element shape and size on the calculation of contact force between different blocks. Then, three types of heat conduction models, which can deal with heat conduction in continuum and discontinuum, are incorporated into NCDDAM to simulate the heat conduction effects of rock masses. Finally, a two-way staggered algorithm is adopted in the context of NCDDAM to simulate the thermo-mechanical coupling effects in rock masses. Several benchmark examples are used to verify the correctness of the enriched NCDDAM in handling contact problems, heat conduction problems and thermo-mechanical coupling problems. The effects of time step size on the accuracy of NCDDAM for both thermal simulation and mechanical simulation are investigated detailly. In addition, the thermal cracking processes of rock masses for both experiment and engineering scales are simulated by the enriched NCDDAM. The numerical results indicate that the enriched NCDDAM is a powerful tool to simulate the thermo-mechanical coupling processes of rock masses.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117543"},"PeriodicalIF":6.9,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive parameter selection in nudging based data assimilation","authors":"Aytekin Çıbık ,&nbsp;Rui Fang ,&nbsp;William Layton ,&nbsp;Farjana Siddiqua","doi":"10.1016/j.cma.2024.117526","DOIUrl":"10.1016/j.cma.2024.117526","url":null,"abstract":"<div><div>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 <span><math><mi>χ</mi></math></span> and the density of observational locations, <span><math><mi>H</mi></math></span>, 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.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117526"},"PeriodicalIF":6.9,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interpretable A-posteriori error indication for graph neural network surrogate models","authors":"Shivam Barwey ,&nbsp;Hojin Kim ,&nbsp;Romit Maulik","doi":"10.1016/j.cma.2024.117509","DOIUrl":"10.1016/j.cma.2024.117509","url":null,"abstract":"<div><div>Data-driven surrogate modeling has surged in capability in recent years with the emergence of graph neural networks (GNNs), which can operate directly on mesh-based representations of data. The goal of this work is to introduce an interpretability enhancement procedure for GNNs, with application to unstructured mesh-based fluid dynamics modeling. Given a black-box baseline GNN model, the end result is an interpretable GNN model that isolates regions in physical space, corresponding to sub-graphs, that are intrinsically linked to the forecasting task while retaining the predictive capability of the baseline. These structures identified by the interpretable GNNs are adaptively produced in the forward pass and serve as explainable links between the baseline model architecture, the optimization goal, and known problem-specific physics. Additionally, through a regularization procedure, the interpretable GNNs can also be used to identify, during inference, graph nodes that correspond to a majority of the anticipated forecasting error, adding a novel interpretable error-tagging capability to baseline models. Demonstrations are performed using unstructured flow field data sourced from flow over a backward-facing step at high Reynolds numbers, with geometry extrapolations demonstrated for ramp and wall-mounted cube configurations.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117509"},"PeriodicalIF":6.9,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel Hybrid Particle Element Method (HPEM) for large deformation analysis in solid mechanics","authors":"Huangcheng Fang,&nbsp;Zhen-Yu Yin","doi":"10.1016/j.cma.2024.117530","DOIUrl":"10.1016/j.cma.2024.117530","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117530"},"PeriodicalIF":6.9,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isogeometric topology optimization (ITO) of fiber reinforced composite structures considering stress constraint and load uncertainties","authors":"Jin Cheng ,&nbsp;Hengrui Fu ,&nbsp;Zhenyu Liu ,&nbsp;Jianrong Tan","doi":"10.1016/j.cma.2024.117537","DOIUrl":"10.1016/j.cma.2024.117537","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117537"},"PeriodicalIF":6.9,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrov–Galerkin Dynamical Low Rank Approximation: SUPG stabilisation of advection-dominated problems","authors":"Fabio Nobile,&nbsp;Thomas Trigo Trindade","doi":"10.1016/j.cma.2024.117495","DOIUrl":"10.1016/j.cma.2024.117495","url":null,"abstract":"<div><div>We propose a novel framework of generalised Petrov–Galerkin Dynamical Low Rank (DLR) Approximations in the context of random PDEs. It builds on the standard Dynamical Low Rank Approximations in their Dynamically Orthogonal formulation. It allows to seamlessly build-in many standard and well-studied stabilisation techniques that can be framed as either generalised Galerkin methods, or Petrov–Galerkin methods. The framework is subsequently applied to the case of Streamline Upwind/Petrov–Galerkin (SUPG) stabilisation of advection-dominated problems with small stochastic perturbations of the transport field. The norm-stability properties of two time discretisations are analysed. Numerical experiments confirm that the stabilising properties of the SUPG method naturally carry over to the DLR framework.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117495"},"PeriodicalIF":6.9,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling high temperature progressive failure in C/SiC composites using a phase field model: Oxidation rate controlled process","authors":"Xiaofei Hu ,&nbsp;Siyuan Tan ,&nbsp;Huiqian Xu ,&nbsp;Zhi Sun ,&nbsp;Tong Wang ,&nbsp;Lang Min ,&nbsp;Zilong Wang ,&nbsp;Weian Yao","doi":"10.1016/j.cma.2024.117544","DOIUrl":"10.1016/j.cma.2024.117544","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117544"},"PeriodicalIF":6.9,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spherical harmonics-based pseudo-spectral method for quantitative analysis of symmetry breaking in wrinkling of shells with soft cores","authors":"Jan Zavodnik ,&nbsp;Miha Brojan","doi":"10.1016/j.cma.2024.117529","DOIUrl":"10.1016/j.cma.2024.117529","url":null,"abstract":"<div><div>A 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.</div><div>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.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117529"},"PeriodicalIF":6.9,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-level adaptive mesh refinement strategy for unified phase field fracture modeling using unstructured conformal simplices","authors":"Anshul Pandey,&nbsp;Sachin Kumar","doi":"10.1016/j.cma.2024.117514","DOIUrl":"10.1016/j.cma.2024.117514","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117514"},"PeriodicalIF":6.9,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the novel zero-order overshooting LMS algorithms by design for computational dynamics","authors":"Yazhou Wang ,&nbsp;Dean Maxam ,&nbsp;Nikolaus A. Adams ,&nbsp;Kumar K. Tamma","doi":"10.1016/j.cma.2024.117522","DOIUrl":"10.1016/j.cma.2024.117522","url":null,"abstract":"<div><div>In this paper, a novel time-weighted residual methodology is developed in the two-field form of structural dynamics problems to enable generalized class of optimal zero-order overshooting Linear Multi-Step (LMS) algorithms by design. For the first time, we develop a novel time-weighted residual methodology in the two-field form of the second-order time-dependent systems, leading to the newly proposed ZOO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> schemes (zero-order overshooting with 4 roots) to achieve: second-order time accuracy in displacement, velocity, and acceleration, unconditional stability, zero-order overshooting, controllable numerical dissipation/dispersion, and minimal computational complexity. Particularly, it resolves the issues in existing single-step methods, which exhibit first-order overshooting in displacement and/or velocity. Additionally, the relationship between the newly proposed ZOO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> schemes and existing methods is contrasted and analyzed, providing a new and in-depth understanding to the recent advances in literature from the time-weighted residual viewpoint. Rigorous numerical analysis, verification, and validation via various numerical examples are presented to substantiate the significance of the proposed methodology in accuracy and stability analysis, particularly demonstrating the advancements towards achieving zero-order overshooting in numerically dissipative schemes for linear/nonlinear structural dynamics problems.</div></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":"433 ","pages":"Article 117522"},"PeriodicalIF":6.9,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}