Computational Mechanics最新文献_第2页

The discontinuous strain method: accurately representing fatigue and failure 非连续应变法：准确表现疲劳和失效

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-08-14 DOI: 10.1007/s00466-024-02526-9

Leon Herrmann, Alireza Daneshyar, Stefan Kollmannsberger

{"title":"The discontinuous strain method: accurately representing fatigue and failure","authors":"Leon Herrmann, Alireza Daneshyar, Stefan Kollmannsberger","doi":"10.1007/s00466-024-02526-9","DOIUrl":"https://doi.org/10.1007/s00466-024-02526-9","url":null,"abstract":"Fatigue simulation requires accurate modeling of unloading and reloading. However, classical ductile damage models treat deformations after complete failure as irrecoverable—which leads to unphysical behavior during unloading. This unphysical behavior stems from the continued accumulation of plastic strains after failure, resulting in an incorrect stress state at crack closure. As a remedy, we introduce a discontinuous strain in the additive elasto-plastic strain decomposition, which absorbs the excess strain after failure. This allows representing pre- and post-cracking regimes in a fully continuous setting, wherein the transition from the elasto-plastic response to cracking can be triggered at any arbitrary stage in a completely smooth manner. Moreover, the presented methodology does not exhibit the spurious energy release observed in hybrid approaches. In addition, our approach guarantees mesh-independent results by relying on a characteristic length scale—based on the discretization’s resolution. We name this new methodology the discontinuous strain method. The proposed approach requires only minor modifications of conventional plastic-damage routines. To convey the method in a didactic manner, the algorithmic modifications are first discussed for one- and subsequently for two-/three-dimensional implementations. Using a simple ductile constitutive model, the discontinuous strain method is validated against established two-dimensional benchmarks. The method is, however, independent of the employed constitutive model. Elastic, plastic, and damage models may thus be chosen arbitrarily. Furthermore, computational efforts associated with the method are minimal, rendering it advantageous for accurately representing low-cycle fatigue but potentially also for other scenarios requiring a discontinuity representation within a plastic-damage framework. An open-source implementation is provided to make the proposed method accessible.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"1 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multi-physics modeling of the 2022 NIST additive manufacturing benchmark (AM-Bench) test series 2022 年 NIST 增材制造基准 (AM-Bench) 测试系列的多物理场建模

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-08-13 DOI: 10.1007/s00466-024-02532-x

Qiming Zhu, Ze Zhao, Jinhui Yan

引用次数: 0

Nonlinear dynamic analysis of shear- and torsion-free rods using isogeometric discretization and outlier removal 利用等几何离散化和离群值去除对无剪切和无扭杆进行非线性动态分析

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-30 DOI: 10.1007/s00466-024-02527-8

Thi-Hoa Nguyen, Bruno A. Roccia, René R. Hiemstra, Cristian G. Gebhardt, Dominik Schillinger

{"title":"Nonlinear dynamic analysis of shear- and torsion-free rods using isogeometric discretization and outlier removal","authors":"Thi-Hoa Nguyen, Bruno A. Roccia, René R. Hiemstra, Cristian G. Gebhardt, Dominik Schillinger","doi":"10.1007/s00466-024-02527-8","DOIUrl":"https://doi.org/10.1007/s00466-024-02527-8","url":null,"abstract":"In this paper, we present a discrete formulation of nonlinear shear- and torsion-free rods introduced by Gebhardt and Romero (Acta Mechanica 232(10):3825–3847, 2021) that uses isogeometric discretization and robust time integration. Omitting the director as an independent variable field, we reduce the number of degrees of freedom and obtain discrete solutions in multiple copies of the Euclidean space (left( mathbb {R}^3right) ), which is larger than the corresponding multiple copies of the manifold (left( mathbb {R}^3 varvec{times } S^2right) ) obtained with standard Hermite finite elements. For implicit time integration, we choose the same integration scheme as Gebhardt and Romero in (2021) that is a hybrid form of the midpoint and the trapezoidal rules. In addition, we apply a recently introduced approach for outlier removal by Hiemstra et al. (Comput Methods Appl Mech Eng 387:114115, 2021) that reduces high-frequency content in the response without affecting the accuracy, ensuring robustness of our nonlinear discrete formulation. We illustrate the efficiency of our nonlinear discrete formulation for static and transient rods under different loading conditions, demonstrating good accuracy in space, time and the frequency domain. Our numerical example coincides with a relevant application case, the simulation of mooring lines.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"11 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unstructured moving least squares material point methods: a stable kernel approach with continuous gradient reconstruction on general unstructured tessellations 非结构移动最小二乘材料点方法：在一般非结构网格上采用连续梯度重构的稳定核方法

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-23 DOI: 10.1007/s00466-024-02524-x

Yadi Cao, Yidong Zhao, Minchen Li, Yin Yang, Jinhyun Choo, Demetri Terzopoulos, Chenfanfu Jiang

{"title":"Unstructured moving least squares material point methods: a stable kernel approach with continuous gradient reconstruction on general unstructured tessellations","authors":"Yadi Cao, Yidong Zhao, Minchen Li, Yin Yang, Jinhyun Choo, Demetri Terzopoulos, Chenfanfu Jiang","doi":"10.1007/s00466-024-02524-x","DOIUrl":"https://doi.org/10.1007/s00466-024-02524-x","url":null,"abstract":"The material point method (MPM) is a hybrid Eulerian Lagrangian simulation technique for solid mechanics with significant deformation. Structured background grids are commonly employed in the standard MPM, but they may give rise to several accuracy problems in handling complex geometries. When using (2D) unstructured triangular or (3D) tetrahedral background elements, however, significant challenges arise (e.g., cell-crossing error). Substantial numerical errors develop due to the inherent ({mathcal {C}}^0) continuity property of the interpolation function, which causes discontinuous gradients across element boundaries. Prior efforts in constructing ({mathcal {C}}^1) continuous interpolation functions have either not been adapted for unstructured grids or have only been applied to 2D triangular meshes. In this study, an unstructured moving least squares MPM (UMLS-MPM) is introduced to accommodate 2D and 3D simplex tessellation. The central idea is to incorporate a diminishing function into the sample weights of the MLS kernel, ensuring an analytically continuous velocity gradient estimation. Numerical analyses confirm the method’s capability in mitigating cell crossing inaccuracies and realizing expected convergence.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"14 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Space–time isogeometric analysis of tire aerodynamics with complex tread pattern, road contact, and tire deformation 具有复杂胎面花纹、路面接触和轮胎变形的轮胎空气动力学时空等距分析

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-17 DOI: 10.1007/s00466-024-02520-1

Takashi Kuraishi, Zhaojing Xu, Kenji Takizawa, Tayfun E. Tezduyar, Tsuyoshi Kakegami

{"title":"Space–time isogeometric analysis of tire aerodynamics with complex tread pattern, road contact, and tire deformation","authors":"Takashi Kuraishi, Zhaojing Xu, Kenji Takizawa, Tayfun E. Tezduyar, Tsuyoshi Kakegami","doi":"10.1007/s00466-024-02520-1","DOIUrl":"https://doi.org/10.1007/s00466-024-02520-1","url":null,"abstract":"The space–time (ST) computational method “ST-SI-TC-IGA” and recently-introduced complex-geometry isogeometric analysis (IGA) mesh generation methods have enabled high-fidelity computational analysis of tire aerodynamics with near-actual tire geometry, road contact, tire deformation, and aerodynamic influence of the car body. The tire geometries used in the computations so far included the longitudinal and transverse grooves. Here, we bring the tire geometry much closer to an actual tire geometry by using a complex, asymmetric tread pattern. The complexity of the tread pattern required an updated version of the NURBS Surface-to-Volume Guided Mesh Generation (NSVGMG) method, which was introduced recently and is robust even in mesh generation for complex shapes with distorted boundaries. The core component of the ST-SI-TC-IGA is the ST Variational Multiscale (ST-VMS) method, and the other key components are the ST Slip Interface (ST-SI) and ST Topology Change (ST-TC) methods and the ST Isogeometric Analysis (ST-IGA). They all play a key role. The ST-TC, uniquely offered by the ST framework, enables moving-mesh computation even with the topology change created by the contact between the tire and the road. It deals with the contact while maintaining high-resolution flow representation near the tire.The computational analysis we present is the first of its kind and shows the effectiveness of the ST-SI-TC-IGA and NSVGMG in tire aerodynamic analysis with complex tread pattern, road contact, and tire deformation.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"44 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141720279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modeling and simulation of chemo-elasto-plastically coupled battery active particles 化学弹性塑性耦合电池活性粒子的建模与仿真

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-16 DOI: 10.1007/s00466-024-02499-9

Raphael Schoof, Johannes Niermann, Alexander Dyck, Thomas Böhlke, Willy Dörfler

{"title":"Modeling and simulation of chemo-elasto-plastically coupled battery active particles","authors":"Raphael Schoof, Johannes Niermann, Alexander Dyck, Thomas Böhlke, Willy Dörfler","doi":"10.1007/s00466-024-02499-9","DOIUrl":"https://doi.org/10.1007/s00466-024-02499-9","url":null,"abstract":"As an anode material for lithium-ion batteries, amorphous silicon offers a significantly higher energy density than the graphite anodes currently used. Alloying reactions of lithium and silicon, however, induce large deformation and lead to volume changes up to 300%. We formulate a thermodynamically consistent continuum model for the chemo-elasto-plastic diffusion-deformation behavior of amorphous silicon and it’s alloy with lithium based on finite deformations. In this paper, two plasticity theories, i.e. a rate-independent theory with linear isotropic hardening and a rate-dependent one, are formulated to allow the evolution of plastic deformations and reduce occurring stresses. Using modern numerical techniques, such as higher order finite element methods as well as efficient space and time adaptive solution algorithms, the diffusion-deformation behavior resulting from both theories is compared. In order to further increase the computational efficiency, an automatic differentiation scheme is used, allowing for a significant speed up in assembling time as compared to an algorithmic linearization for the global finite element Newton scheme. Both plastic approaches lead to a more heterogeneous concentration distribution and to a change to tensile tangential Cauchy stresses at the particle surface at the end of one charging cycle. Different parameter studies show how an amplification of the plastic deformation is affected. Interestingly, an elliptical particle shows only plastic deformation at the smaller half axis. With the demonstrated efficiency of the applied methods, results after five charging cycles are also discussed and can provide indications for the performance of lithium-ion batteries in long term use.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"83 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141720281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Physics-informed neural network estimation of material properties in soft tissue nonlinear biomechanical models 物理信息神经网络估算软组织非线性生物力学模型中的材料特性

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-16 DOI: 10.1007/s00466-024-02516-x

Federica Caforio, Francesco Regazzoni, Stefano Pagani, Elias Karabelas, Christoph Augustin, Gundolf Haase, Gernot Plank, Alfio Quarteroni

{"title":"Physics-informed neural network estimation of material properties in soft tissue nonlinear biomechanical models","authors":"Federica Caforio, Francesco Regazzoni, Stefano Pagani, Elias Karabelas, Christoph Augustin, Gundolf Haase, Gernot Plank, Alfio Quarteroni","doi":"10.1007/s00466-024-02516-x","DOIUrl":"https://doi.org/10.1007/s00466-024-02516-x","url":null,"abstract":"The development of biophysical models for clinical applications is rapidly advancing in the research community, thanks to their predictive nature and their ability to assist the interpretation of clinical data. However, high-resolution and accurate multi-physics computational models are computationally expensive and their personalisation involves fine calibration of a large number of parameters, which may be space-dependent, challenging their clinical translation. In this work, we propose a new approach, which relies on the combination of physics-informed neural networks (PINNs) with three-dimensional soft tissue nonlinear biomechanical models, capable of reconstructing displacement fields and estimating heterogeneous patient-specific biophysical properties and secondary variables such as stresses and strains. The proposed learning algorithm encodes information from a limited amount of displacement and, in some cases, strain data, that can be routinely acquired in the clinical setting, and combines it with the physics of the problem, represented by a mathematical model based on partial differential equations, to regularise the problem and improve its convergence properties. Several benchmarks are presented to show the accuracy and robustness of the proposed method with respect to noise and model uncertainty and its great potential to enable the effective identification of patient-specific, heterogeneous physical properties, e.g. tissue stiffness properties. In particular, we demonstrate the capability of PINNs to detect the presence, location and severity of scar tissue, which is beneficial to develop personalised simulation models for disease diagnosis, especially for cardiac applications.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"9 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141720280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A discontinuous Galerkin/cohesive zone model approach for the computational modeling of fracture in geometrically exact slender beams 用于几何精确细长梁断裂计算建模的非连续伽勒金/粘合区模型方法

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-12 DOI: 10.1007/s00466-024-02521-0

Sai Kubair Kota, Siddhant Kumar, Bianca Giovanardi

{"title":"A discontinuous Galerkin/cohesive zone model approach for the computational modeling of fracture in geometrically exact slender beams","authors":"Sai Kubair Kota, Siddhant Kumar, Bianca Giovanardi","doi":"10.1007/s00466-024-02521-0","DOIUrl":"https://doi.org/10.1007/s00466-024-02521-0","url":null,"abstract":"Slender beams are often employed as constituents in engineering materials and structures. Prior experiments on lattices of slender beams have highlighted their complex failure response, where the interplay between buckling and fracture plays a critical role. In this paper, we introduce a novel computational approach for modeling fracture in slender beams subjected to large deformations. We adopt a state-of-the-art geometrically exact Kirchhoff beam formulation to describe the finite deformations of beams in three-dimensions. We develop a discontinuous Galerkin finite element discretization of the beam governing equations, incorporating discontinuities in the position and tangent degrees of freedom at the inter-element boundaries of the finite elements. Before fracture initiation, we enforce compatibility of nodal positions and tangents weakly, via the exchange of variationally-consistent forces and moments at the interfaces between adjacent elements. At the onset of fracture, these forces and moments transition to cohesive laws modeling interface failure. We conduct a series of numerical tests to verify our computational framework against a set of benchmarks and we demonstrate its ability to capture the tensile and bending fracture modes in beams exhibiting large deformations. Finally, we present the validation of our framework against fracture experiments of dry spaghetti rods subjected to sudden relaxation of curvature.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"14 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141609631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A membrane finite element for fast simulation of overlapping beads geometry during direct energy deposition additive manufacturing 用于快速模拟直接能量沉积增材制造过程中重叠珠几何形状的膜有限元

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-10 DOI: 10.1007/s00466-024-02525-w

Eric Feulvarch, Alain Rassineux, Jean-Christophe Roux, Alexey Sova, Cédric Pouvreau, François Josse

{"title":"A membrane finite element for fast simulation of overlapping beads geometry during direct energy deposition additive manufacturing","authors":"Eric Feulvarch, Alain Rassineux, Jean-Christophe Roux, Alexey Sova, Cédric Pouvreau, François Josse","doi":"10.1007/s00466-024-02525-w","DOIUrl":"https://doi.org/10.1007/s00466-024-02525-w","url":null,"abstract":"The aim of this paper is to propose a fast FEM strategy for simulating molten metal deposition geometry during additive manufacturing for studying the influence of the sequence of deposition on the geometry. The approach is inspired by the algorithm initially proposed by Feulvarch et al. (Eur J Mech A 89:104290, 2021) for coatings. In this article, the membrane finite element is notably improved and extended for simulating of a large stack of deposits in order to study the building of 3D geometries. A constant vertical evolution rate of the surface tension is introduced to adjust the geometry of the free surface of the molten pool which depends on the hydrodynamics of the liquid phase. The simulation is very fast because it is carried out on a 2D mesh composed of linear triangles that corresponds to the sole free surface of the liquid phase at each time step. Moreover, the implicit nonlinear algorithm developed has the advantage of avoiding matrix systems resolution (reduced RAM memory, efficient parallel computing). In addition, a simple and robust remeshing procedure is detailed in order to avoid too large distortions of the triangular elements during the ’inflating’ stage of the workpiece. Its interest lies in the fact that it does not require any field projection typically employed in remeshing procedures, as the geometry serves as the only historical data required to resume FEM computations following each remeshing step. Examples are proposed to clearly evidence the efficiency and robustness of the method developed in terms of geometry and CPU time.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"3 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141584893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spontaneous emergence of deformation bands in single-crystal plasticity simulations at small strain 小应变时单晶塑性模拟中变形带的自发出现

IF 4.1 2区工程技术

Computational Mechanics Pub Date : 2024-07-09 DOI: 10.1007/s00466-024-02519-8

M. Ryś, M. Kursa, H. Petryk

{"title":"Spontaneous emergence of deformation bands in single-crystal plasticity simulations at small strain","authors":"M. Ryś, M. Kursa, H. Petryk","doi":"10.1007/s00466-024-02519-8","DOIUrl":"https://doi.org/10.1007/s00466-024-02519-8","url":null,"abstract":"In metal single crystals, the observed formation of deformation banding pattern has been explained by greater latent hardening of slip systems than their self-hardening, which promotes spatial segregation of plastic slips and lamination towards single-slip domains. Numerical studies focusing on the formation of deformation bands usually involved initial imperfections, boundary-induced heterogeneity, or the postulate of minimal global energy expenditure which additionally promoted non-uniformity of deformation. This article analyses the case when no such mechanism enforcing locally non-uniform deformation is implemented in the finite element (FE) method, while the global system of equations of incremental equilibrium is solved in a standard way. The new finding in this paper is that the deformation banding pattern can appear spontaneously in FE simulations of homogeneous single crystals even in the absence of any mechanism favouring deformation banding in the numerical code. This has been demonstrated in several examples in the small strain formalism using a plane-strain model in which the twelve fcc slip systems are reduced to three effective plastic slip mechanisms. Incremental slips are determined at the Gauss-point level either by incremental work minimization in the rate-independent case or by rate-dependent regularization. In the rate-independent approach, the trust-region algorithm is developed for the selection of active slip systems with the help of the augmented Lagrangian method. Conditions under which a banding pattern appears spontaneously or is suppressed are discussed. In particular, a critical rate sensitivity exponent is identified.","PeriodicalId":55248,"journal":{"name":"Computational Mechanics","volume":"24 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141576691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0