Computers and Geotechnics最新文献

Stability of conical foundations on anisotropic clay: A comprehensive three-dimensional study on V-H-M failure envelopes 各向异性粘土上锥形地基的稳定性：关于 V-H-M 破坏包络的综合三维研究

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-16 DOI: 10.1016/j.compgeo.2024.106906

Duy Tan Tran , Jim Shiau , Van Qui Lai , Suraparb Keawsawasvong

This paper is concerned with the V-H-M failure envelopes for conical foundations under combined loadings on anisotropic clay. The study employs the three-dimensional finite element limit analysis (3D FELA) technique and utilizes the well-established Anisotropic Undrained Shear (AUS) failure criteria. The focus of the study is on evaluating the influences of the cone apex angle (β) and the anisotropic factor (r_e) on the bearing capacity of conical foundations subjected to external forces of vertical force (V), horizontal force (H), and moment (M). The combinations of V-H, V-M, and H-M load spaces are analyzed using dimensionless output parameters (V/s_uTCA, H/s_uTCA, M/s_uTCAD), and the various characteristics of failure mechanisms of the conical foundation are examined. Alongside FELA, the study introduces an innovative machine learning approach using Categorical Boosting (CATBoost), Extreme Gradient Boosting (XGBoost), and Gradient Boosting Machine (GBM) to evaluate the correlation between input parameters and their outcomes. The proposed machine learning models are rigorously verified and validated with the CATBoost model, showing exceptional agreement with numerical results, as demonstrated by an impressive R² value of 99.99 %. The present study is a practical and efficient method for evaluating the 3D failure envelope of conical foundations on anisotropic clay under general loading conditions in (V-H-M) space.

本文主要研究各向异性粘土在组合荷载作用下锥形地基的 V-H-M 破坏包络。研究采用了三维有限元极限分析（3D FELA）技术，并使用了成熟的各向异性排水剪切（AUS）破坏标准。研究的重点是评估锥顶角 (β) 和各向异性系数 (re) 对承受垂直力 (V)、水平力 (H) 和力矩 (M) 等外力的锥形地基承载力的影响。使用无量纲输出参数（V/suTCA、H/suTCA、M/suTCAD）分析了 V-H、V-M 和 H-M 荷载空间的组合，并研究了锥形地基破坏机制的各种特征。除 FELA 外，该研究还引入了一种创新的机器学习方法，使用分类提升（CATBoost）、极梯度提升（XGBoost）和梯度提升机（GBM）来评估输入参数与其结果之间的相关性。提出的机器学习模型与 CATBoost 模型进行了严格的验证和确认，显示出与数值结果的极高一致性，令人印象深刻的 R2 值高达 99.99 %。本研究是评估各向异性粘土上锥形地基在 (V-H-M) 空间一般加载条件下的三维破坏包络的一种实用而高效的方法。

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引用次数: 0

Effect of the connection mode on the dynamic characteristics of the pile-wheel composite foundation for offshore wind turbines 连接模式对海上风力涡轮机桩轮复合地基动态特性的影响

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-15 DOI: 10.1016/j.compgeo.2024.106908

Zijian Yang, Xinjun Zou, Minhua Zhou, Lanyi Huang

This study elucidates the horizontal vibration response of the monopile-wheel composite foundation in terms of coupled arrangement. In this paper, the displayed expression of the lateral resistance and resisting moment provided by the rotating wheel and embedded pile are represented by using the linear elastic Winkler foundation model, in which the springs and dashpot coefficients are derived by Biot’s poroelastic theory and plane-strain model. The hydrodynamic force along the foundation shaft is obtained by the radiation wave theory. A connection degree coefficient is defined to describe the change of wheel action. Then, the dynamic governing equations for the vibrating pile based on the Timoshenko beam theory are re-established. Combined with foundation bottom boundary condition, the frequency domain analytical solutions for the horizontal and rocking impedances at the head of the composite foundation are obtained. A comparison with some existing results is carried out to verify the correctness and reasonableness of the proposed model. Finally, systematic studies are conducted to analyze the horizontal vibration characteristics of the innovative foundation under different pile-wheel connection mode. The results from these calculation examples show that the pile-wheel composite foundation with decoupled or coupled arrangement has its own advantages in resisting deformation.

本研究从耦合布置的角度阐明了单桩-轮复合地基的水平振动响应。本文使用线性弹性温克勒地基模型来表示旋转轮和嵌入桩所提供的侧阻力和阻力矩的显示表达式，其中弹簧和冲头系数由 Biot 的孔弹性理论和平面应变模型推导得出。沿地基轴的流体动力由辐射波理论求得。定义了一个连接度系数来描述车轮作用的变化。然后，根据季莫申科梁理论重新建立了振动桩的动力控制方程。结合地基底部边界条件，得到了复合地基头部水平阻抗和摇摆阻抗的频域解析解。通过与一些已有结果的对比，验证了所提模型的正确性和合理性。最后，系统研究分析了不同桩轮连接模式下创新地基的水平振动特性。这些计算实例的结果表明，解耦或耦合布置的桩轮复合地基在抵抗变形方面具有自身的优势。

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引用次数: 0

Particle shape distribution effects on the critical strength of granular materials 颗粒形状分布对颗粒材料临界强度的影响

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-13 DOI: 10.1016/j.compgeo.2024.106896

Sergio Carrasco , David Cantor , Carlos Ovalle , Frédéric Dubois

This study investigates the influence of correlations between particle morphology and gradation on the critical shear strength of three-dimensional granular assemblies via numerical simulations. While grain shape is acknowledged to play a central role in the mechanical behavior of granular media, only a few works have explored the combined effects of grain shapes varying with grain size. Employing three-dimensional discrete-element simulations, we explore the shear behavior of samples with diverse particle size distributions, where grain shapes (ranging from spheres to very angular polyhedra) are assigned based on the relative size of each particle. Using drained triaxial shear tests, we analyze the macroscopic behavior up to large deformation levels. Micro-mechanical analyses are also conducted to understand the underlying mechanisms governing the observed macroscopic behavior, highlighting the role of grain connectivity and force transmission. Surprisingly, well graded samples composed of coarse angular grains and fine rounded ones are not capable of developing higher shear strengths than uniform samples with the same diversity on grain shapes. Conversely, samples where coarser grains are rounded and fines are angular, show constant shear strength as the particle size distribution becomes broader. These findings underscore the importance of simultaneously considering grain size and shape distributions for the assessment of realistic granular soil behavior.

本研究通过数值模拟研究了颗粒形态和级配之间的相关性对三维颗粒集合体临界剪切强度的影响。虽然粒形被认为在颗粒介质的力学行为中起着核心作用，但只有少数研究探讨了粒形随粒度变化的综合影响。利用三维离散元素模拟，我们探索了具有不同粒度分布的样品的剪切行为，其中粒形（从球形到角度极大的多面体）是根据每个颗粒的相对尺寸分配的。利用排水三轴剪切试验，我们分析了直至大变形水平的宏观行为。我们还进行了微观力学分析，以了解观察到的宏观行为的基本机制，突出晶粒连通性和力传递的作用。令人惊讶的是，与具有相同晶粒形状多样性的均匀样品相比，由粗角晶粒和细圆晶粒组成的良好分级样品并不能产生更高的剪切强度。相反，粗粒呈圆形、细粒呈角形的样品，随着粒度分布的扩大，其剪切强度保持不变。这些发现强调了同时考虑粒度和粒形分布对评估实际粒状土行为的重要性。

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引用次数: 0

Investigation of elastoplastic constitutive model of rubber-sand mixture 橡胶-砂混合物弹塑性结构模型研究

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-13 DOI: 10.1016/j.compgeo.2024.106904

Zhen-Dong Cui, Min-Zhe Xu, Xiao-Dong Wang

The rubber-sand mixture (RSM) has been extensively applied in the engineering construction as a lightweight filling material. However, the mechanical characteristics of RSMs are still not completely understood and the constitutive model used to simulate the RSMs by FEM analysis is also lacking. This study presents a newly developed constitutive model based on the critical state framework that describes the stress–strain relationship and dilatancy behavior of RSMs with different rubber contents. The relationship between rubber contents and critical state parameters was introduced in the established constitutive model. The comparisons of test results and model calculations show the RSM model can better capture the strain softening behavior, dilatancy characteristics and the critical state of RSMs. The RSM model was compiled by the user-defined material (UMAT) in ABAQUS and then utilized to simulate the triaxial tests. The developed RSM model is suitable for the triaxial compressive test using monotonic radial loading in triaxial space. The calculation results demonstrate the correctness and effectiveness of the developed model, which can be used as a reference in the engineering practice.

橡胶砂混合物（RSM）作为一种轻质填充材料已被广泛应用于工程建设中。然而，人们对 RSM 的力学特性仍不完全了解，也缺乏用于通过有限元分析模拟 RSM 的构成模型。本研究基于临界状态框架提出了一种新开发的构成模型，用于描述不同橡胶含量的 RSM 的应力-应变关系和膨胀行为。在已建立的构成模型中引入了橡胶含量与临界状态参数之间的关系。试验结果和模型计算结果的比较表明，RSM 模型能更好地捕捉 RSM 的应变软化行为、膨胀特性和临界状态。RSM 模型由 ABAQUS 中的用户自定义材料（UMAT）编制，然后用于模拟三轴试验。所开发的 RSM 模型适用于在三轴空间中使用单调径向加载的三轴压缩试验。计算结果证明了所开发模型的正确性和有效性，可作为工程实践的参考。

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引用次数: 0

Evaluation of the shear stiffness and load redistribution of framed structures affected by tunnelling 评估受隧道工程影响的框架结构的剪切刚度和荷载重新分布情况

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-13 DOI: 10.1016/j.compgeo.2024.106899

Jingmin Xu , Zehui Yu , Rui Chen , Tao Xu , Churong Chen , Ziqi Wang

This technical note examines the shear distortion of plane strain framed structures resulting from tunnelling-induced surface differential settlements. An equation for calculating the shear stiffness is derived, considering various structural parameters. The effectiveness of the proposed method is validated through both experimental and finite element modeling results, with its accuracy emphasized by comparison with existing methods. Additionally, a method for estimating the redistribution of pressure beneath the foundation of plane strain framed buildings due to tunnelling is proposed and validated through numerical simulations which adopt an advanced soil constitutive model. The parametric study further demonstrates the applicability of the proposed methods for estimating shear stiffness in three-dimensional structures characterized by similar vertical wall and horizontal slab stiffness. The research findings provide tunnelling engineers with a tool for the rapid estimation of shear stiffness in framed structures and a reliable evaluation of pressure redistribution beneath foundations caused by tunnelling.

本技术说明探讨了隧洞引起的表面差异沉降对平面应变框架结构造成的剪切变形。考虑到各种结构参数，得出了剪切刚度计算公式。通过实验和有限元建模结果验证了所提方法的有效性，并通过与现有方法的比较强调了其准确性。此外，还提出了一种估算平面应变框架建筑地基下因隧道开挖而产生的压力重新分布的方法，并通过采用先进土壤构成模型的数值模拟进行了验证。参数研究进一步证明了所提出的方法适用于估算垂直墙和水平板刚度相似的三维结构的剪切刚度。研究成果为隧道工程师提供了一种工具，用于快速估算框架结构的剪切刚度，并对隧道开挖造成的地基下压力重新分布进行可靠评估。

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引用次数: 0

DEM Validation for impact Wave propagation in dry sand: A comparison with experimental results 干砂中冲击波传播的 DEM 验证：与实验结果的比较

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-13 DOI: 10.1016/j.compgeo.2024.106901

K Balamonica , Goh Siang Huat

In wave propagation problems, soil is often idealized as a continuum, neglecting its granular nature. Discrete element method (DEM) offers an explicit representation of granular interactions, providing valuable insights into its micro-mechanics. However, previous studies using DEM primarily focused on small-strain scenarios like bender element tests, with limited exploration of transient loads like those resulting from impacts or blasts. This research investigates the capability of DEM for modelling impact wave propagation in dry sand. A dry sand column under 1-D impact loading is simulated using DEM and compared with experimental data. Key characteristics of the wave propagation, such as wave velocity and attenuation, are compared to assess the ability of DEM to capture the dispersive wave and attenuative characteristics of dry sand to transient loads. In addition, the importance of characterising the viscous damping in DEM to model the wave propagation under realistic loading conditions is highlighted.

在波传播问题中，土壤通常被理想化为连续体，而忽略了其颗粒性质。离散元法（DEM）明确表示了颗粒的相互作用，为了解颗粒的微观力学提供了宝贵的资料。然而，以往使用 DEM 进行的研究主要集中在弯管元件测试等小应变情况，对冲击或爆炸等瞬态载荷的研究有限。本研究探讨了 DEM 模拟干砂中冲击波传播的能力。使用 DEM 模拟了一维冲击载荷下的干沙柱，并与实验数据进行了比较。对波速和衰减等波传播的主要特征进行比较，以评估 DEM 在捕捉干沙对瞬态荷载的分散波和衰减特征方面的能力。此外，还强调了在 DEM 中描述粘性阻尼的重要性，以模拟实际加载条件下的波传播。

引用次数: 0

Compression characteristics and particle scale stress distribution of sand-rubber mixtures with particle size disparity effect 具有粒度差异效应的砂橡胶混合物的压缩特性和颗粒尺度应力分布

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-12 DOI: 10.1016/j.compgeo.2024.106905

Deyun Liu , Zhen-Yu Yin

This research investigates the particle-scale stress transmission characteristics at the end of isotropic consolidation stage for sand-rubber mixtures, focusing on the effects of particle size disparity, density, and stress levels. The discrete element method was adopted with total 450 simulations being conducted for sand-rubber mixtures with increasing size disparities to quantify the particle-scale stress distribution between sand and rubber materials. This study reveals that the variation of coordination number and void ratio for sand-rubber mixtures align with those observed in conventional gap-graded soils, while the inclusion of deformable rubber clumps significantly increases coordination number values. A complex interplay between packing density and stress level was evident, illustrating the nuanced role of rubber in stress transmission. As packing density and stress levels decrease, the efficacy of deformable rubber clumps in stress transfer increases. An inverse relationship between the efficiency of stress transmission and particle size disparity was observed for all these sand-rubber mixtures. The findings indicate that, despite variations in size disparity, the proportion of stress transferred by rubber remains consistently lower than their volumetric contribution. This study underscores the complexities of using sand-rubber mixtures and highlights that the effect of particle property disparity outweighs the that of particle property disparity.

本研究调查了砂-橡胶混合物在各向同性固结阶段末期的颗粒尺度应力传递特性，重点关注颗粒尺寸差异、密度和应力水平的影响。研究采用离散元素法，对粒度差异不断增大的砂橡胶混合物进行了 450 次模拟，以量化砂和橡胶材料之间的颗粒级应力分布。研究结果表明，砂橡胶混合物的配位数和空隙率的变化与在传统间隙级配土壤中观察到的变化一致，而加入可变形橡胶团块会显著增加配位数值。堆积密度和应力水平之间的复杂相互作用显而易见，说明了橡胶在应力传递中的微妙作用。随着堆积密度和应力水平的降低，可变形橡胶团块在应力传递中的功效也随之增加。所有这些砂橡胶混合物的应力传递效率与颗粒大小差异之间都存在反比关系。研究结果表明，尽管粒度差异存在变化，但橡胶传递应力的比例始终低于其体积贡献。这项研究强调了使用砂橡胶混合物的复杂性，并突出表明颗粒特性差异的影响大于颗粒特性差异的影响。

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引用次数: 0

Coupled CFD-DEM modelling of clogging of granular columns by cohesive fines 粘性细粒堵塞颗粒柱的 CFD-DEM 耦合模型

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-12 DOI: 10.1016/j.compgeo.2024.106902

Thao Doan , Buddhima Indraratna , Thanh T. Nguyen , Cholachat Rujikiatkamjorn

The ubiquitous phenomenon of particle migration and clogging in porous media, particularly when involving cohesive fines necessitates a critical need for in-depth understanding from a microscale perspective. Therefore, this study aims to elucidate the migration and clogging behaviour of polydisperse cohesive fines across a granular medium by using the coupled Computational Fluid Dynamics-Discrete Element Method (CFD-DEM). Primary governing factors including the relative coarse–fine size ratio and the strength of interparticle cohesive force through the concept of bond number are examined in detail from both macro- and micromechanical perspectives. The results reveal that the presence of interparticle cohesion drastically modifies the migration of fine particles, associating with a notable reduction in the infiltration ratio and an increased likelihood of particle deposition. This study innovatively explores the combined effect of the coarse–fine size ratios and cohesive strength on the migratory behaviour of fines through the infiltration ratio and critical time ratio, whereby clogging carries substantial implications on the geo-hydraulic performance of the granular medium. Moreover, in the context of cohesive fines, the Authors propose a comprehensive and novel algorithm for detecting and analysing cohesion-induced agglomeration effect. The results reveal that the formation and breakage of agglomerates due to the metastability of cohesive bonds between fines can be captured to explain the unstable flows occurring through the clogged zones.

颗粒在多孔介质中的迁移和堵塞现象无处不在，尤其是涉及粘性细粒时，因此亟需从微观角度进行深入了解。因此，本研究旨在利用计算流体力学-离散元耦合方法（CFD-DEM）阐明多分散粘性细粒在颗粒介质中的迁移和堵塞行为。从宏观和微观机械的角度详细研究了主要控制因素，包括相对粗细尺寸比和通过粘合力概念计算的颗粒间粘合力强度。研究结果表明，颗粒间内聚力的存在极大地改变了细颗粒的迁移，同时显著降低了渗透比，增加了颗粒沉积的可能性。这项研究创新性地探讨了粗细粒径比和内聚强度通过渗透比和临界时间比对细颗粒迁移行为的综合影响，其中堵塞对颗粒介质的地质水文性能具有重大影响。此外，针对内聚性细粒材料，作者提出了一种全面而新颖的算法，用于检测和分析内聚引起的团聚效应。研究结果表明，由于细粒之间内聚键的易变性而导致的团聚体的形成和破裂，可以用来解释堵塞区发生的不稳定流。

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引用次数: 0

Simple and efficient geotechnical reliability-based design based on transformed limit state functions by target reliability-oriented sampling 通过以可靠性为导向的目标取样，基于变换后的极限状态函数，进行简单高效的岩土工程可靠性设计

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-12 DOI: 10.1016/j.compgeo.2024.106877

Bin Li , Yong-kai Shen , Zi-Jun Cao , Qi Wan , Chen-Zhe Ma

This paper develops a novel reliability-based design (RBD) approach from a new perspective. The approach is relatively simple as it does not need direct reliability calculations for different designs and gives the critical design satisfying the target reliability requirement without involving a trial-and-error procedure. It specifies the critical design, which is unknown, as the one that achieves the limit state at its corresponding design point given a prescribed target reliability requirement. This is inverse to geotechnical reliability calculations based on the design point where the design point is determined for calculating the reliability, which is unknown, given a design. From this inverse perspective, geotechnical RBD is transformed into determination of a design point given a target reliability level and its corresponding design. In this study, this is accomplished by a target reliability-oriented sampling algorithm and transforming the original limit state function (LSF) to represent the design parameter as a function of uncertain parameters. The proposed approach is illustrated by three design examples. Results show that the proposed approach provides accurate design outcomes in a cost-effective way. It provides a useful complementary tool to existing RBD methods due to its simplicity and efficiency.

本文从一个新的角度提出了一种新颖的基于可靠性的设计（RBD）方法。这种方法相对简单，因为它不需要对不同的设计进行直接的可靠性计算，并能给出满足目标可靠性要求的临界设计，而不涉及试错程序。它将未知的临界设计定义为在规定的目标可靠性要求下，在相应设计点达到极限状态的设计。这与基于设计点的岩土工程可靠性计算是相反的，在设计点的确定是为了计算给定设计的未知可靠性。从这一反向角度来看，岩土工程的可靠性和可重复性设计被转化为根据目标可靠性水平及其相应的设计确定设计点。本研究采用以目标可靠性为导向的采样算法，并将原始极限状态函数（LSF）转换为代表设计参数的不确定参数函数。本文通过三个设计实例对所提出的方法进行了说明。结果表明，所提出的方法能以经济有效的方式提供精确的设计结果。由于其简单高效，它为现有的 RBD 方法提供了有用的补充工具。

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引用次数: 0

A constitutive model of rock based on strain cone surface and the parameter calibration method with high efficiency 基于应变锥面的岩石构成模型及高效参数校准方法

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-11-12 DOI: 10.1016/j.compgeo.2024.106876

Jie Li , Shaobin Hou , Yalong Jiang , Helin Fu , Kaixun Hu

The elastic and plastic strains of rock during the compression process cannot be accurately identified by common constitutive models. This paper investigated the strain evolution of rock under monotonic compressive load by referring to results from damage-controlled cyclic loading tests, and discussed the contradiction between the flow rule of traditional elastoplastic constitutive models and real plastic strain development. Therefore, a strain cone surface constitutive model was proposed, where the yield surface was replaced with strain cone surfaces for both elastic and plastic strains. The magnitude and direction of vectors regarding elastic and plastic strain increments occurring on these conical surfaces were explored. Then, the proposed model was validated against cyclic loading tests. Furthermore, a robust parameter calibration method was developed based on genetic algorithm, and its ability to search for optimal parameters was verified by comparing the simulated constitutive relationships with the practical stress–strain curves. The results show that the traditional flow rule could be incompatible with the real plastic strain variation. In contrast, the proposed model could accurately simulate the evolution of elastic and plastic strains, demonstrating high precision and applicability. Moreover, the calibration method enables the determination of model parameters with high accuracy and efficiency.

岩石在压缩过程中的弹塑性应变无法通过普通的构造模型准确识别。本文参考破坏控制循环加载试验的结果，研究了岩石在单调压缩荷载作用下的应变演化过程，探讨了传统弹塑性构造模型的流动规律与实际塑性应变发展之间的矛盾。因此，提出了一种应变锥面构成模型，即用应变锥面代替屈服面来表示弹性应变和塑性应变。研究了这些锥形表面上出现的弹性和塑性应变增量的矢量大小和方向。然后，根据循环加载试验对所提出的模型进行了验证。此外，还开发了一种基于遗传算法的稳健参数校准方法，并通过比较模拟构成关系和实际应力应变曲线，验证了该方法寻找最佳参数的能力。结果表明，传统的流动规则可能与实际塑性应变变化不相容。相比之下，所提出的模型可以准确模拟弹性应变和塑性应变的演变，显示出较高的精度和适用性。此外，校准方法还能高精度、高效率地确定模型参数。

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引用次数: 0