International Journal of Solids and Structures最新文献_第2页

Dispersive properties of metamaterial beams with rod-like resonators: A coupled axial-flexural analysis 具有棒状谐振腔的超材料光束的色散特性：耦合轴向弯曲分析

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-19 DOI: 10.1016/j.ijsolstr.2024.113145

Andrea Burlon

This paper addresses the propagation of coupled axial-flexural waves in metamaterial beams with rod-like resonators. Utilizing an exact frequency-dependent stiffness method, based on Euler–Bernoulli beam assumption for rods and host beam, and fully accounting for axial-flexural coupling phenomena, several adimensional parametric analyses are performed for investigating the dispersive properties of the metamaterial beams. The analyses reveal novel and relevant aspects unaddressed in previous studies. Firstly, they show that certain rod configurations lead to significant interference between flexural resonance and the band gaps opened by axial resonance, whereas other configurations enable flexural resonance to open substantial band gaps without interference from axial resonance. Results are complemented by 3D finite element analyses proving evidence of the findings and validating the method. Additional analyses demonstrate that adding a tip mass to the rods, while keeping the total mass of the resonator unchanged, can significantly reduce the opening frequency of the band gaps and can attenuate or remove the interference caused by flexural resonance within the band gaps opened by axial resonance; the rotational inertia of the tip mass can also play a significant role in removing flexural resonance interference. Notably, the paper also reveals that the attenuation phenomena for the coupled problem with a single set of rods are governed by the opening of weak band gaps, rather than by traditional band gaps; this aspect is elucidated by showing Bloch mode shapes of the infinite metamaterial beam and frequency response of the corresponding finite beam. Results and proposed design prove to be useful and promising for locally resonant beams featuring rod-like resonators, both as an alternative to traditional beam-like resonators and for their applicability in the 3D printing process of locally resonant structures, where rods serve as elastic elements in constructing the resonators.

本文研究了耦合轴向弯曲波在具有棒状谐振腔的超材料梁中的传播。利用精确的频率相关刚度方法，基于欧拉-伯努利梁对杆和主梁的假设，并充分考虑轴向弯曲耦合现象，进行了一些一维参数分析，以研究超材料梁的色散特性。这些分析揭示了以前研究中未涉及的新颖和相关方面。首先，他们表明，某些杆配置导致弯曲共振和轴向共振打开的带隙之间的显著干扰，而其他配置使弯曲共振打开大量带隙而不受轴向共振的干扰。结果由三维有限元分析补充，证明了研究结果的证据并验证了该方法。进一步分析表明，在保持谐振腔总质量不变的情况下，增加棒的尖端质量可以显著降低带隙的打开频率，并可以衰减或消除轴向共振打开的带隙内弯曲共振引起的干扰；尖端质量的转动惯量也可以在消除弯曲共振干扰方面发挥重要作用。值得注意的是，本文还揭示了单组棒耦合问题的衰减现象是由弱带隙的打开而不是传统带隙控制的；通过展示无限超材料梁的布洛赫振型和相应有限梁的频率响应来阐明这方面。结果和提出的设计被证明对于具有棒状谐振器的局部谐振梁是有用的和有前途的，既可以作为传统的棒状谐振器的替代品，也可以用于局部谐振结构的3D打印过程，其中棒状谐振器作为构造谐振器的弹性元件。

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引用次数: 0

An accurate and efficient method based on the dynamic stiffness matrix for analyzing wave propagation in defective lattice structures 基于动态刚度矩阵的精确高效方法，用于分析缺陷晶格结构中的波传播

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-18 DOI: 10.1016/j.ijsolstr.2024.113147

B.W. Yan, Q. Gao

In this study, we present an efficient and accurate method for analyzing wave propagation in lattice structures with periodic defects, which are composed of three-dimensional (3D) unit cells arranged infinitely in two or three directions, with defects existing periodically along the directions of the arrangement. The unit cell is composed of 3D beams, and the dynamic stiffness formulation of the 3D beam is developed by combining the Timoshenko-Ehrenfest, Rayleigh-Love and torsion theories. Based on the dynamic stiffness matrix, any number or order of natural frequencies of defective lattice structures can be calculated accurately and efficiently using the Wittrick-Williams algorithm. By combining it with the Bloch theorem, the proposed method can be used to calculate the dispersion curves of lattice structures with periodic defects. The accuracy and efficiency of the proposed method are demonstrated through numerical examples. Additionally, the effects of periodic defects in the lattice structures on the bandgap are analyzed.

在本研究中，我们提出了一种高效、精确的方法，用于分析具有周期性缺陷的晶格结构中的波传播。这种结构由沿两个或三个方向无限排列的三维（3D）单元格组成，缺陷沿排列方向周期性存在。单元格由三维梁组成，通过结合 Timoshenko-Ehrenfest、Rayleigh-Love 和扭转理论，建立了三维梁的动态刚度公式。在动态刚度矩阵的基础上，利用 Wittrick-Williams 算法可以精确高效地计算出缺陷晶格结构的任意数量或顺序的固有频率。通过与布洛赫定理相结合，所提出的方法可用于计算具有周期性缺陷的晶格结构的频散曲线。通过数值示例证明了所提方法的准确性和高效性。此外，还分析了晶格结构中的周期性缺陷对带隙的影响。

引用次数: 0

An analytical model for the phase transformation front propagation in superelastic SMA under impact tensile loading 冲击拉伸加载下超弹性 SMA 中相变前沿传播的分析模型

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-16 DOI: 10.1016/j.ijsolstr.2024.113151

Y. Wang , B. Hou , S. Roux , H. Zhao

Shape-memory alloys (SMAs) exhibit superelastic behavior due to reversible phase transformations. Under dynamic (impact) loading, phase transformation is experimentally observed to occur along a band whose front propagates throughout the specimen. However, unlike the static case, the nucleation and propagation of these bands require further understanding. Recently, a Finite Element Method (FEM) simulation based on Thamburaja and Nikabdullah’s constitutive model successfully reproduced the experimental observations. In this study, the model is revisited in the specific case of a one-dimensional dynamic tension test, which allows for the derivation of an analytical closed-form one-dimensional stress–strain relation. When compared to FEM simulations of a single element, this analytical solution shows excellent agreement. From this closed form stress–strain relation, the propagation speed of the phase transformation shock front can be analytically computed. It also highlights that the shock front speed is primarily controlled by the strain reached after the complete transformation from the Austenite to the Martensite phase.

形状记忆合金（SMA）因可逆相变而表现出超弹性行为。在动态（冲击）加载条件下，实验观察到相变沿着一条带发生，其前沿在整个试样中传播。然而，与静态情况不同，这些带的成核和传播需要进一步了解。最近，基于 Thamburaja 和 Nikabdullah 构成模型的有限元法（FEM）模拟成功地再现了实验观察结果。在本研究中，我们在一维动态拉伸试验的特定情况下重新审视了该模型，从而可以推导出封闭形式的一维应力-应变分析关系。与单个元素的有限元模拟相比，该分析解决方案显示出极佳的一致性。根据这一封闭式应力应变关系，可以分析计算出相变冲击前沿的传播速度。它还突出表明，冲击前沿速度主要受奥氏体向马氏体相完全转变后所达到的应变控制。

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引用次数: 0

Vibration characteristics of cylindrical shells with discontinuous connections based on the spectral element method 基于谱元法的具有不连续连接的圆柱形壳体的振动特性

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-16 DOI: 10.1016/j.ijsolstr.2024.113148

Chai Kai , Liu Junfeng , Lou Jingjun , Liu Shuyong

Common shell of revolution, such as cylindrical, conical, and spherical shells, are widely used in marine, aerospace, and other engineering fields due to their excellent support and pressure-resistant properties. Research on their vibration characteristics has progressed from single shells to composite shells, from ribbed shells to those with complex internal substructures, and from uniform to discontinuous connections. The discontinuities in wave propagation at the boundaries of discontinuously connected cylindrical shells result in highly complex equation of vibration control, leading to limited studies in this area. This study first models the uniform cylindrical shell and annular plate as spectral elements, using trigonometric and Bessel functions to describe displacement solutions and obtain vibration responses for arbitrary boundary conditions. Then, based on artificial virtual spring theory and the weighted least squares method, the discontinuous connection between the cylindrical shell and annular plate is modeled as a circumferentially varying stiffness distribution, leading to the derivation of dynamic stiffness matrices for both continuous and discontinuous connections. Finite element simulations are conducted using ABAQUS to analyze the vibration characteristics of the discontinuously connected cylindrical shell under free, clamped, and simply supported boundary conditions. Finally, an experimental setup is used to measure the vibration response under harmonic excitation and perform impedance testing with an impact hammer. The results show that the spectral element method accurately calculates the natural frequencies of the stiffened cylindrical shell, with an overall error of less than 2 %, while the maximum error for the experimental shell is 5.8 %.

常见的旋转壳体，如圆柱形、圆锥形和球形壳体，因其优异的支撑和抗压性能，被广泛应用于船舶、航空航天和其他工程领域。对其振动特性的研究已经从单一壳体发展到复合壳体，从带肋壳体发展到具有复杂内部子结构的壳体，从均匀连接发展到不连续连接。不连续连接的圆柱形壳体在边界处波传播的不连续性导致振动控制方程非常复杂，因此这方面的研究非常有限。本研究首先将均匀圆柱壳和环形板建模为谱元件，使用三角函数和贝塞尔函数描述位移解，并获得任意边界条件下的振动响应。然后，根据人工虚拟弹簧理论和加权最小二乘法，将圆柱壳和环形板之间的非连续连接建模为圆周变化的刚度分布，从而推导出连续和非连续连接的动态刚度矩阵。使用 ABAQUS 进行有限元模拟，分析非连续连接的圆柱形壳体在自由、夹紧和简单支撑边界条件下的振动特性。最后，使用实验装置测量谐波激励下的振动响应，并用冲击锤进行阻抗测试。结果表明，谱元法准确计算了加劲圆柱形壳体的固有频率，总体误差小于 2%，而实验壳体的最大误差为 5.8%。

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引用次数: 0

Minimum energy combined and separated bounds on elastic constants of transversely-isotropic composites 横向各向异性复合材料弹性常数的最小能量组合约束和分离约束

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-15 DOI: 10.1016/j.ijsolstr.2024.113134

Duc-Chinh Pham

The considered linearly-elastic transversely-isotropic composite (TIC) is composed of

n

isotropic, or more generally, transversely-isotropic components sharing the materials’ common symmetry axis with that of the macroscopic material. Using the basic minimum energy and complementary energy principles with certain free-parameter-dependent mixed-longitudinal-transverse-mode strain and stress trial fields, various combination bounds involving some sets of the macroscopic (effective) mixed-mode elastic constants of the composite, which are inter-connected via the constitutive relations, have been established. Choosing the appropriate parameter values of/or optimizing over the free parameters in those inequalities, the separated bounds on the major effective mixed-transverse-longitudinal-mode elastic constants, including the transverse bulk modulus

K^{e f f}

, the longitudinal Young modulus

E^{e f f}

, and the longitudinal Poisson’s ratio

ν^{e f f}

, are derived, beside the classical arithmetic and harmonic average bounds on the pure-mode ones — the transverse shear (

μ^{e f f}

) and longitudinal shear (

{\bar{μ}}^{e f f}

) moduli. The separated bounds on 4 remaining effective mixed-mode elastic constants are also obtained. The illustrative numerical comparisons of the bounds, in the two component case, with those for the special subclass of unidirectional transversely-isotropic composites (UTIC), having the unidirectional cylindrical boundaries between the component materials parallel to their symmetry axis, and the exact coated-cylinder assemblage and laminate models are presented. The extreme models cover substantial parts between the bounds for TIC; however the laminate models lie outside the bounds for the subclass UTIC.

所考虑的线弹性横向各向同性复合材料（TIC）由 n 个各向同性或更一般的横向各向同性成分组成，这些成分与宏观材料共享共同的对称轴。利用基本的最小能量和互补能量原理以及某些与自由参数相关的纵向-横向混合模式应变和应力试验场，建立了涉及复合材料某些宏观（有效）混合模式弹性常数集的各种组合约束，这些常数集通过构成关系相互连接。选择这些不等式中自由参数的适当参数值或对自由参数进行优化，除了对纯模式弹性常数--横向剪切模量（μeff）和纵向剪切模量（μ̄eff）--的经典算术和谐波平均约束外，还推导出了主要有效横纵混合模式弹性常数的分离约束，包括横向体积模量 Keff、纵向杨氏模量 Eeff 和纵向泊松比 νeff。同时还得到了其余 4 个有效混合模式弹性常数的分离约束。在双组分情况下，对这些边界与单向横向各向同性复合材料（UTIC）特殊子类的边界进行了说明性数值比较，单向横向各向同性复合材料的各组分材料之间的单向圆柱边界平行于其对称轴，而精确的涂覆圆柱装配和层压模型也是如此。极端模型覆盖了 TIC 边界之间的大部分区域，而层压模型则超出了 UTIC 子类的边界。

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引用次数: 0

Stability discussion and application study of pseudo-corner models 伪角模型的稳定性讨论和应用研究

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-13 DOI: 10.1016/j.ijsolstr.2024.113136

Tianyin Zhang , Xianhong Han

Accurate plastic flow modelling under complex working conditions is crucial for metal deformation simulations. Recently, some advanced pseudo-corner models have been developed to describe corner effects and analyze strain localization problems. The present work consists of three parts. The first part discusses the intrinsic stability of the pseudo-corner model class, which forms the premise of application analysis. The second part applies the pseudo-corner models and the associated flow rule (AFR) to buckling onset estimation, plastic post-buckling analysis and shear band analysis. The experimental conditions are strictly reproduced and the optimal model parameters are determined. The results reveal that the pseudo-corner models and AFR are indistinguishable in the buckling onset estimation. AFR overestimates the post-buckling strength of circular tubes under axial compression, and cannot reproduce the shear band development during sheet bending; while the pseudo-corner models have better prediction performance in both scenarios. The results also suggest that the parameter values of pseudo-corner models are apparently inconsistent in the above two types of problems. Then in the third part, two representative influencing factors including strain gradient plasticity and initial imperfections are discussed, and this inconsistency is finally attributed to the shortwave surface defect which however is usually neglected by previous studies.

复杂工作条件下的精确塑性流动建模对于金属变形模拟至关重要。最近，人们开发了一些先进的伪转角模型来描述转角效应和分析应变定位问题。本研究包括三个部分。第一部分讨论了伪转角模型类的内在稳定性，这是应用分析的前提。第二部分将伪角模型和相关流动规则（AFR）应用于屈曲起始估计、屈曲后塑性分析和剪切带分析。严格再现了实验条件，并确定了最佳模型参数。结果表明，伪角模型和 AFR 在屈曲起始估计方面没有区别。AFR 高估了圆管在轴向压缩下的屈曲后强度，并且无法再现板材弯曲过程中的剪切带发展；而伪角模型在这两种情况下都具有更好的预测性能。结果还表明，在上述两类问题中，伪拐角模型的参数值明显不一致。第三部分讨论了两个具有代表性的影响因素，包括应变梯度塑性和初始缺陷，最后将这种不一致性归因于短波表面缺陷，然而之前的研究通常忽略了这一点。

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引用次数: 0

A new porous constitutive model for additively manufactured PLA 聚乳酸添加剂制造的新型多孔结构模型

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-12 DOI: 10.1016/j.ijsolstr.2024.113131

P. Areias, N. Silvestre, M.F. Vaz, M. Leite

We introduce a new specific hyperelastic/plastic model and porosity evolution law able to capture the deformation and damage of additively manufactured PLA-N polymers (Fused Filament Fabrication — FFF). Porosity growth is driven by projecting the right Cauchy–Green tensor in the normal to the deposition direction and by solving a local maximization problem. Fracture energy is introduced directly in the resulting law by means of a length scale. A full finite-strain plasticity model is adopted, based on the Hosford yield criterion. Strain softening is regularized with a gradient-enhanced technique, which is solved in tandem with the equilibrium equations. A comprehensive analysis of the hyperelastic transversely isotropic/porous constitutive law is performed, with physical insight on the directional strain softening behavior. A normalized CT test specimen is used to qualitatively assess the effect of deposition direction on the crack path and to investigate the effect of mesh density in the load/displacement curves. We then present a comparison with our experimental results for a cellular PLA-N beam composed of 3 × 13 cells, in terms of crack behavior and load/displacement results. Sequential collapse of the cells and strain localization match the experimental observations.

我们介绍了一种新的特定超弹性/塑性模型和孔隙率演化规律，能够捕捉到添加式制造的聚乳酸-N 聚合物（熔融长丝制造-FFF）的变形和损坏。通过在沉积方向的法线上投影右 Cauchy-Green 张量，并通过解决局部最大化问题来驱动孔隙率增长。断裂能通过长度标度直接引入所得到的定律中。根据霍斯福屈服准则，采用了完整的有限应变塑性模型。采用梯度增强技术对应变软化进行正则化，并与平衡方程同步求解。对超弹性横向各向同性/多孔组织法进行了全面分析，并对定向应变软化行为提出了物理见解。我们使用归一化 CT 试样来定性评估沉积方向对裂纹路径的影响，并研究网格密度对载荷/位移曲线的影响。然后，我们对由 3 × 13 个单元组成的聚乳酸-N 单元梁的裂纹行为和载荷/位移结果与实验结果进行了比较。单元的顺序塌陷和应变局部化与实验观察结果一致。

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引用次数: 0

Multiscale model for bottom-up prediction of failure parameters of unidirectional carbon-fiber-reinforced composite lamina from the atomic to filament-scales, and its application to failure modeling of open-hole quasi-isotropic composite laminates 自下而上预测单向碳纤维增强复合材料层压板从原子到细丝尺度失效参数的多尺度模型及其在开孔准各向同性复合材料层压板失效建模中的应用

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-09 DOI: 10.1016/j.ijsolstr.2024.113130

Tadashi Watanabe , Yoshiaki Kawagoe , Yamato Hoshikawa , Yosuke Nakai , Kazuki Ryuzono , Tomonaga Okabe

A multiscale model is developed to comprehensively predict the failure parameters associated with the elasto-plasticity of a unidirectional carbon-fiber-reinforced composite lamina; the prediction is performed according to the resin-matrix design. The developed model involves quantum-chemical reaction-path calculations, molecular-dynamics simulations, and micromechanical analyses at the filament scale. The presented model is further combined with an advanced numerical approach developed based on an extended finite-element method, to analyze composites at the laminate scale. Using the established four-scale model, the open-hole tension and compression of a quasi-isotropic laminate are simulated, starting from the composition of an epoxy resin. The predicted elasto-plastic properties and strengths of a unidirectional lamina are in good agreement with the previously reported experimental results. Furthermore, the strengths predicted for the open-hole tests are also plausible, as they are similar to the experimental values reported in literature. The established multiscale model is expected to be useful in composite-material development as it facilitates rapid and exhaustive analysis.

建立了一个多尺度模型，以全面预测与单向碳纤维增强复合材料薄片弹塑性相关的失效参数；预测是根据树脂-基质设计进行的。所开发的模型包括量子化学反应路径计算、分子动力学模拟以及丝状尺度的微观力学分析。该模型还与基于扩展有限元法开发的先进数值方法相结合，对复合材料进行层压分析。利用已建立的四尺度模型，从环氧树脂的成分出发，模拟了准各向同性层压板的开孔拉伸和压缩。预测的单向层压板弹塑性能和强度与之前报告的实验结果十分吻合。此外，开孔试验预测的强度也是可信的，因为它们与文献报道的实验值相似。所建立的多尺度模型有助于进行快速、详尽的分析，因此有望在复合材料开发中发挥作用。

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引用次数: 0

Coupled thermo-mechanical modeling of reflective cracking in flexible pavements 柔性路面反射裂缝的热机械耦合建模

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-07 DOI: 10.1016/j.ijsolstr.2024.113129

Mohammad Rahmani, Yong-Rak Kim

This study presents a coupled thermo-mechanical finite element modeling to simulate the reflective cracking of flexible pavements. The method integrates principles from computational fracture mechanics, specifically focusing on the mixture-level fracture characteristics of bituminous materials, and links them with a structural-level model for the deformation and cracking of pavements. Recognizing the substantial impact of mechanical and environmental factors on pavement damage performance, this study considers time- and temperature-dependent deformations and fracture of bituminous mixtures. To address this, the finite element method incorporated with cohesive zone fracture was used to account for the viscoelastic properties and temperature-dependent fracture characteristics of the bituminous mixtures. The concept of multiphysics modeling is elucidated within this context. To assess the capability of the modeling approach and its sensitivity under varying pavement design variables and loading conditions, a total of 14 cases with varying mixture properties, pavement layer configurations, and loading conditions (i.e., thermal loading only and coupled thermal–mechanical loading) were considered. The computational modeling presented in this study has the scientific rigor to predict complex fracture of mixtures and pavements with promising modelling efficiency with a few laboratory tests. Model simulation results demonstrate the effects of mixture properties and their layer configurations, which implies that coupled multiphysics modeling such as herein can differentiate the pavement damage performance influenced by interactive design variables and loading conditions. The pavement failure process is intensified when thermal and mechanical loads are applied simultaneously.

本研究提出了一种热力-机械耦合有限元模型，用于模拟柔性路面的反射裂缝。该方法综合了计算断裂力学的原理，特别关注沥青材料的混合物级断裂特性，并将其与路面变形和开裂的结构级模型联系起来。认识到机械和环境因素对路面损坏性能的重大影响，本研究考虑了沥青混合物随时间和温度变化的变形和断裂。为此，采用了包含内聚区断裂的有限元方法，以考虑沥青混合物的粘弹性和随温度变化的断裂特性。在此背景下，多物理场建模的概念得到了阐释。为了评估建模方法的能力及其在不同路面设计变量和加载条件下的灵敏度，共考虑了 14 个不同混合物特性、路面层配置和加载条件（即仅热加载和热机械耦合加载）的案例。本研究提出的计算模型具有科学严谨性，可预测混合物和路面的复杂断裂，并通过少量实验室测试实现良好的建模效率。模型模拟结果表明了混合料特性及其层配置的影响，这意味着本研究中的多物理场耦合建模可以区分受交互式设计变量和加载条件影响的路面损坏性能。当同时施加热荷载和机械荷载时，路面破坏过程会加剧。

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引用次数: 0

Defect dynamics modeling of mesoscale plasticity 中尺度塑性缺陷动力学建模

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-11-07 DOI: 10.1016/j.ijsolstr.2024.113132

Phu Cuong Nguyen , Nicole Aragon , Ill Ryu

The collective motion of defects and their interaction are the basic building blocks for plastic deformation and corresponding mechanical behaviors of crystalline metals. Especially, dislocations among various defects are the “carrier” of plastic deformation in many crystalline materials, particularly ductile materials. To get a fundamental understanding of plastic deformation mechanisms, it calls for an integrated computational platform to simultaneously capture detailed defects characteristics across several length scales together with corresponding macroscopic mechanical response. In this paper, we present a three-dimensional mesoscale defect dynamics model to directly couple the three dimensional discrete dislocation dynamics model with continuum finite element method, aiming at capturing both size dependent plasticity at micron-, and submicron scale and constitutive behaviors at larger scales where such size-dependence disappear. Using non-singular dislocation theories, our model could accurately consider both short- and long-range elastic interactions between multiple dislocation segments with even higher computational efficiency than traditional dislocation dynamics simulations, together with the careful consideration of crystal/material rotation in the coupled framework. In addition, our model could directly model dislocation nucleation from stress concentrators such as a void, crack and indentor tip, which could allow us to investigate various defects’ motion and their mutual interactions, predicting macroscopic mechanical response of complex structures. The developed concurrently coupled model could also consider multiphysical phenomena by solving coupled governing equations in finite element framework, which could shed light on complex defect behaviors under various physical environments.

缺陷的集体运动及其相互作用是结晶金属塑性变形和相应机械行为的基本组成部分。特别是在许多晶体材料，尤其是韧性材料中，各种缺陷之间的位错是塑性变形的 "载体"。为了从根本上了解塑性变形机制，需要一个综合计算平台，以同时捕捉多个长度尺度上的详细缺陷特征和相应的宏观力学响应。在本文中，我们提出了一种三维中尺度缺陷动力学模型，将三维离散位错动力学模型与连续有限元方法直接结合起来，旨在捕捉微米和亚微米尺度上的尺寸依赖性塑性以及尺寸依赖性消失的更大尺度上的构成行为。我们的模型采用非鞘状位错理论，能准确地考虑多个位错段之间的短程和长程弹性相互作用，其计算效率甚至高于传统的位错动力学模拟，同时在耦合框架中仔细考虑了晶体/材料的旋转。此外，我们的模型可直接模拟来自空洞、裂缝和压痕尖端等应力集中点的位错成核，从而研究各种缺陷的运动及其相互影响，预测复杂结构的宏观力学响应。所开发的并行耦合模型还可以通过在有限元框架内求解耦合控制方程来考虑多物理现象，从而揭示各种物理环境下的复杂缺陷行为。

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引用次数: 0