【新文速递】2024年10月18日固体力学SCI期刊最新文章

 

今日更新：International Journal of Solids and Structures 1 篇，Mechanics of Materials 3 篇，Thin-Walled Structures 5 篇

International Journal of Solids and Structures

An optimal penalty method for the joint stiffening in beam models of additively manufactured lattice structures

T. Cadart, T. Hirschler, S. Bahi, S. Roth, F. Demoly, N. Lebaal

doi:10.1016/j.ijsolstr.2024.113107

增材制造晶格结构梁模型中节点加劲的最优惩罚方法

Additive manufacturing is revolutionizing structural design, with lattice structures becoming increasingly prominent due to their superior mechanical properties. However, simulating these structures quickly and accurately using the finite element method (FEM) remains challenging. Recent research has highlighted beam element simulation within FEM as a more efficient alternative to traditional solid FE simulations, achieving similar accuracy with reduced computational resources. However, a significant challenge is managing the lack of rigidity at nodes and the prevalence of low aspect ratio beams. While various methodologies have been proposed to address these issues, there is still a gap in the comprehensive evaluation of their limitations. An optimal node penalization methodology is required to expand the limited range of accurately represented lattice behavior. A preliminary study investigates lattice geometries through comparative analysis of solid and beam FE simulations. Built on this, we developed a methodology suitable to linear, dynamics and nonlinear beam FE simulations, contributing to enhanced computational speed and accuracy. Several lattice structures were printed using material jetting and quasi-static compressive tests were conducted to validate the methodology’s accuracy. The numerical results reveal a good accuracy between the proposed beam FE methodology and the experimental data, offering a better alternative to conventional FEM for energy absorption in terms of computing time.

增材制造正在彻底改变结构设计，晶格结构由于其优越的机械性能而变得越来越突出。然而，使用有限元方法快速准确地模拟这些结构仍然具有挑战性。最近的研究强调，有限元中的梁单元模拟是传统实体有限元模拟的更有效的替代方法，可以在减少计算资源的情况下达到相似的精度。然而，一个重大的挑战是管理节点缺乏刚度和低纵横比梁的流行。虽然提出了各种方法来解决这些问题，但在全面评价其局限性方面仍然存在差距。需要一种最优节点惩罚方法来扩展精确表示晶格行为的有限范围。通过对固体和梁有限元模拟的对比分析，初步研究了晶格几何形状。在此基础上，我们开发了一种适用于线性，动态和非线性梁有限元模拟的方法，有助于提高计算速度和准确性。利用材料喷射和准静态压缩实验验证了该方法的准确性。数值结果表明，所提出的梁有限元方法与实验数据具有较好的准确性，在计算时间上优于传统有限元方法。

Mechanics of Materials

Experimental and digital twinning in ZnAlMg coatings

Ahmed Zouari, Mikel Bengoetxea-Aristondo, Filip Siska, Aymen Bouzid, Fabrice Gaslain, Aurélien Chopin, Houssem Eddine Chaieb, Kais Ammar, Pascal Bertho, Joost De Strycker, Jean-Michel Mataigne, Samuel Forest

doi:10.1016/j.mechmat.2024.105173

ZnAlMg涂层的实验孪生和数字孪生

Twinning is a major deformation mechanism in various materials, especially when few dislocation slip systems are operative. It is the case of zinc-rich coatings in galvanised steel sheets, made of pancake grains on a substrate and where the slip systems with a non-vanishing component along the c -axis present high critical resolved shear stress values. In addition, the abrupt lattice orientation change associated to twinning, the stress relaxation during its propagation and the localised nature of its early stages make it difficult to reproduce this deformation mechanism by using classical crystal plasticity models conceived for dislocation slip. In this sense, this work proposes a hierarchy of three twinning models in combination with a dislocation slip crystal plasticity model, for the case of a ZnAlMg coating. These three models are: a relaxed-Taylor model applied to individual crystal orientations of the coating, a “pseudo-slip” model for twinning and a localised twinning model. The latter incorporates a linear softening in the material law accounting for the unstable twinning initiation and enforces twinning lattice reorientation. A microstructure portion extracted from an in-situ SEM tensile experiment on galvanised steel is used to perform 3D full-field finite element simulations within a finite strain formulation. SEM observations and EBSD acquisitions are used to compare simulation and experimental results during the different steps of the in-situ SEM test, regarding the deformation and damage modes of the zinc-rich coating. The focus is set on twinning evolution inside some individual grains, and the pros and the cons of the three models are finally discussed.

孪生是各种材料的主要变形机制，特别是在少数位错滑移系统起作用时。这是镀锌钢板上的富锌涂层的情况，由基底上的煎饼颗粒制成，其中沿c轴具有不消失成分的滑移系统呈现高临界分解剪切应力值。此外，与孪晶相关的晶格取向突变、孪晶传播过程中的应力松弛以及早期阶段的局域性，使得用位错滑移的经典晶体塑性模型难以再现这种变形机制。从这个意义上说，本工作提出了三个孪生模型的层次结构，并结合了ZnAlMg涂层的位错滑移晶体塑性模型。这三种模型是：一种适用于涂层单个晶体取向的松弛泰勒模型，一种用于孪生的“伪滑移”模型和一种局部孪生模型。后者在材料律中包含线性软化，用于解释不稳定的孪晶起始并强制孪晶晶格重定向。从镀锌钢的原位扫描电镜拉伸实验中提取的微观结构部分用于在有限应变公式内进行三维全场有限元模拟。通过SEM观察和EBSD采集，对比了原位SEM测试不同步骤的模拟结果和实验结果，研究了富锌涂层的变形和损伤模式。重点讨论了个别晶粒内部的孪晶演化，并讨论了三种模型的优缺点。

The influences of temperature on the macroscopic elastoplastic behaviors of heterogeneous materials

W.Q. Shen

doi:10.1016/j.mechmat.2024.105176

温度对非均质材料宏观弹塑性行为的影响

The microstructure of heterogeneous materials affectes importantly their macroscopic mechanical behavior. For a thermal-mechanical coupling problem, the temperature also has a significant effect. Firstly, the effect of temperature on the elastic behavior of heterogeneous material has been investigated in the present work with the consideration of its microstructure. Then, an explicit expression of the macroscopic yield criterion has been derived for the plastic behavior of porous material by using the homogenization approach. This yield criterion takes into account explicitly and simultaneously the influence of porosity and the effect of temperature on its overall mechanical behavior. To consider the pressure sensitivity of the matrix, the Drucker–Prager type criterion is adopted at the microscopic scale. After that, the heterogeneous material with a matrix reinforced by rigid inclusions has been studied. The microstructure information, such as the inclusion content, matrix property and the temperature have been considered explicitly in the obtained yield function. The influences of temperature and the confining pressure on the macroscopic material strength are captured by the obtained criterion. Then, the obtained result is applied to describe the temperature-dependent mechanical behaviors of sandstone.

非均相材料的微观结构对其宏观力学行为有重要影响。对于热-力耦合问题，温度也有显著的影响。本文首先从微观结构出发，研究了温度对非均质材料弹性行为的影响。然后，利用均匀化方法导出了多孔材料塑性行为的宏观屈服准则的显式表达式。该屈服准则明确地同时考虑了孔隙率和温度对其整体力学行为的影响。为了考虑基质的压力敏感性，在微观尺度上采用Drucker-Prager型判据。在此基础上，研究了由刚性夹杂物增强基体的非均质材料。得到的屈服函数明确考虑了夹杂物含量、基体性质和温度等微观结构信息。所得准则反映了温度和围压对材料宏观强度的影响。然后，将所得结果应用于描述砂岩随温度变化的力学行为。

Thermalized and mixed meanfield ADP potentials for magnesium hydrides

M. Molinos, M. Ortiz, M.P. Ariza

doi:10.1016/j.mechmat.2024.105175

氢氧化镁的热化和混合平均场ADP电位

We develop meanfield approximation and numerical quadrature schemes for the evaluation of Angular-Dependent interatomic Potentials (ADPs) for magnesium and magnesium hydrides at finite temperature (thermalization) and arbitrary atomic molar fractions (mixing) within a non-equilibrium statistical mechanical framework and derive local equilibrium relations. We numerically verify and experimentally validate the accuracy and fidelity of the resulting thermalized/mixed ADPs (TADPs) by means of selected numerical tests including free entropy, heat capacity, thermal expansion, molar volumes, equation of state and elastic constants. We show that the local equilibrium properties predicted by TADPs agree closely with those computed directly from ADP by means of Molecular Dynamics (MD).

在非平衡统计力学框架下，我们开发了平均场近似和数值正交方案，用于评估镁和氢化物在有限温度（热化）和任意原子摩尔分数（混合）下的角依赖原子间势（ADPs），并推导了局部平衡关系。通过自由熵、热容、热膨胀、摩尔体积、状态方程和弹性常数等数值测试，对所得的热化/混合ADPs （TADPs）进行了数值验证和实验验证。结果表明，用TADPs预测的局部平衡性质与用分子动力学（MD）直接从ADP计算的结果非常吻合。

Thin-Walled Structures

Unraveling anisotropic mechanical behaviors of lithium-ion battery separators: Microstructure insights

Zhiwei Hao, You Gao, Ji Lin, Lubing Wang

doi:10.1016/j.tws.2024.112593

揭示锂离子电池隔膜的各向异性力学行为：微观结构的见解

The mechanical properties of separators significantly affect the electrochemical stability and potential short circuit risks in lithium-ion batteries. An important aspect of their mechanical behavior is their anisotropy, which is predominantly influenced by the microstructures formed during manufacturing process. This study aims to bridge the gap between the anisotropic mechanical features of the separators and their microstructures caused by the manufacturing methods. Initially, we delve into the characterization of separators, featuring their heterogeneous components and orientated arrangement of fibers. Then, we conduct uniaxial tensile tests to measure the stress-strain relationships of separators along the machine direction (MD), diagonal direction (DD), and transverse direction (TD), revealing pronounced anisotropy in both strength and rate sensitivity. Subsequently, image processing techniques is adopted to obtain a representative configuration of separators, which is further divided into fibers and lamellae. According to the manufacturing process of separators, a viscoplastic model is used to describe the mechanical behavior of lamellae while a strengthened viscoplastic model is utilized to mimic the mechanical response of fibers. The finite element analyses underscore the dominant role of orientated fibers in determining anisotropic mechanical properties. Furthermore, we explore the effects of manufacturing and geometry parameters on the separator's anisotropic mechanical behavior. This research provides valuable insights for optimizing manufacturing parameters and enhancing safety measures for lithium-ion batteries.

隔膜的力学性能对锂离子电池的电化学稳定性和潜在短路风险有重要影响。其力学行为的一个重要方面是它们的各向异性，这主要受制造过程中形成的微观组织的影响。本研究旨在弥补由于制造方法造成的隔膜的各向异性力学特性与微观结构之间的差距。首先，我们深入研究了隔膜的特性，包括它们的异质成分和纤维的定向排列。然后，我们进行了单轴拉伸试验，以测量沿机器方向（MD），对角线方向（DD）和横向方向（TD）的应力-应变关系，揭示了强度和速率敏感性的明显各向异性。随后，采用图像处理技术得到具有代表性的隔膜结构，并将其进一步划分为纤维和片层。根据分离机的制造过程，采用粘塑性模型来描述片层的力学行为，采用强化粘塑性模型来模拟纤维的力学响应。有限元分析强调了取向纤维在确定各向异性力学性能方面的主导作用。此外，我们还探讨了制造参数和几何参数对分离器各向异性力学行为的影响。该研究为优化锂离子电池的制造参数和加强安全措施提供了有价值的见解。

Damage behavior of composite honeycomb sandwich structure subject to low-velocity impact and compression-after-impact using experimental and numerical methods

Wanhui Ma, Hongliang Tuo, Qingtian Deng, Xinbo Li

doi:10.1016/j.tws.2024.112594

基于实验和数值方法的复合材料蜂窝夹层结构低速冲击和后冲击压缩损伤行为

The paper studies the damage initiation and evolution of composite honeycomb sandwich structure subject to low-velocity impact and CAI (compression after impact) loadings by a combination of experimental and numerical methods. The impact responses including impact force and energy absorption were obtained through impact tests, and detailed damage analysis was conducted using various testing methods including ultrasonic C-scan, DIC (digital image correlation), infrared thermography and SEM (scanning electron microscope). A damage model based on MMF (micro-mechanics of failure) and cohesive behavior were used to predict the mechanical behavior of composite facesheets, and an elastoplastic constitutive model with ductile damage was used to model the honeycomb core. The experimental and numerical results show good agreements and reveal that the matrix damage, delamination, core crushing and fiber damage will be induced in the composite honeycomb sandwich structure depending on the impact energy levels. During the CAI process, the strain concentration in the impact region will lead to local buckling of the sandwich structure, and the damage expands from the impact region to the free edges along the transverse direction until the final collapse, which will cause an obvious temperature increase in the damage area.

采用实验与数值相结合的方法，研究了复合材料蜂窝夹层结构在低速冲击和冲击后压缩载荷作用下的损伤起裂与演化过程。通过冲击试验获得了包括冲击力和能量吸收在内的冲击响应，并采用超声c扫描、DIC（数字图像相关）、红外热像仪和SEM（扫描电镜）等多种测试方法对其进行了详细的损伤分析。采用基于微破坏力学（MMF）和内聚行为的损伤模型预测复合材料面板的力学行为，采用含延性损伤的弹塑性本构模型模拟蜂窝芯。实验结果与数值计算结果吻合较好，表明不同的冲击能级会诱发复合材料蜂窝夹层结构的基体损伤、分层、芯层破碎和纤维损伤。在CAI过程中，冲击区域的应变集中会导致夹层结构局部屈曲，损伤沿横向方向从冲击区域向自由边缘扩展，直至最终坍塌，从而导致损伤区域温度明显升高。

A one-time training machine learning method for general structural topology optimization

Sen-Zhen Zhan, Xinhong Shi, Xi-Qiao Feng, Zi-Long Zhao

doi:10.1016/j.tws.2024.112595

用于一般结构拓扑优化的一次性训练机器学习方法

Machine learning (ML) methods have found some applications in structural topology optimization. In the existing methods, however, the ML models need to be retrained when the design domains and supporting conditions have been changed, posing a limitation to their wide applications. In this paper, we propose a one-time training ML (OTML) method for general topology optimization, where the self-attention convolutional long short-term memory (SaConvLSTM) model is introduced to update the design variables. An extension–division approach is used to enrich the training sets. By developing a splicing strategy, the training results of a small design space (i.e., a basic cell of either two- or three-dimensions) can be extended to tackling the optimization problem of a large design domain with arbitrary geometric shapes. Using the OTML method, the ML model needs to be trained for only one time, and the trained model can be used directly to solve various optimization problems with arbitrary shapes of design domains, loads, and boundary conditions. In the SaConvLSTM model, the material volume of the post-processed thresholded designs can be precisely controlled, though the control precision of the gray-scale designs might be slightly sacrificed. The effects of model parameters on the computational cost and the result quality are examined. Four examples are provided to demonstrate the high performance of this structural design method. For large-scale optimization problems, the present method can accelerate the structural form-finding process. This study holds a promise in the high-resolution structural form-finding and transdisciplinary computational morphogenesis.

机器学习方法在结构拓扑优化中有一定的应用。然而，在现有方法中，当设计领域和支持条件发生变化时，需要对机器学习模型进行重新训练，这限制了其广泛应用。在本文中，我们提出了一种用于一般拓扑优化的一次性训练机器学习（OTML）方法，其中引入自注意卷积长短期记忆（SaConvLSTM）模型来更新设计变量。采用可拓划分方法丰富训练集。通过开发一种拼接策略，可以将小设计空间（即二维或三维的基本单元）的训练结果扩展到具有任意几何形状的大设计域的优化问题。使用OTML方法，只需要对ML模型进行一次训练，训练后的模型可以直接用于解决具有任意形状的设计域、载荷和边界条件的各种优化问题。在SaConvLSTM模型中，后处理阈值设计的材料体积可以得到精确控制，但灰度设计的控制精度可能会有所牺牲。考察了模型参数对计算成本和结果质量的影响。通过四个算例验证了该结构设计方法的有效性。对于大规模优化问题，该方法可以加快结构寻形过程。该研究在高分辨率结构形态发现和跨学科计算形态发生方面具有前景。

Bearing and tearout of austenitic and duplex stainless steel bolted connections

Yuchen Song, Xue-Mei Lin, Michael C.H. Yam, Yuelin Zhang, Ke Ke, Jia Wang

doi:10.1016/j.tws.2024.112585

奥氏体和双相不锈钢螺栓连接的轴承和拆卸

Due to the unique material characteristics of stainless steel, the bearing and tearout behaviour of stainless steel bolted connections can be different from that of carbon steel bolted connections. Such difference has been gradually recognised in recent design provisions for stainless steel structures. However, it is noteworthy that the existing design methods were mainly developed for austenitic and ferritic stainless steel bolted connections. Their applicability to duplex stainless steel bolted connections is questionable. Moreover, comparing to the bearing failure of stainless steel connections, less attention has been paid to the tearout failure, as well as the combined bearing and tearout failure in multi-bolt connections. To fill these gaps, an experimental and numerical study is carried out on the bearing/tearout behaviour and design of stainless steel bolted connections. The experimental programme includes 22 connection specimens with either single-bolt or multi-bolt configurations, made of austenitic or duplex stainless steel. The experimental tests are supplemented by a comprehensive numerical parametric study with more than 200 individual models, performed based on a validated finite element modelling technique. The obtained test and numerical results are used to assess the effects of different design parameters, as well as the applicability of existing design methods. It is concluded that the ultimate bearing/tearout resistances of austenitic and duplex connections are not simply proportionate to the ultimate strengths of the two materials. Given the same geometric design, the bearing resistance of a duplex connection is considerably higher than that of an austenitic connection, despite the similar ultimate strengths of the two materials. This difference in bearing performance is attributed to the different strain-hardening characteristics of austenitic and duplex materials, as well as the premature shear cracking in austenitic connections that leads to insufficiently developed strain-hardening. In comparison, the tearout resistances of austenitic and duplex connections with the same geometry are much closer, since the smaller end distance leads to more uniform deformations and more completely developed strain-hardening. Moreover, the combined bearing and tearout resistance of multi-bolt connections is found to be lower than the sum of the respective resistances of individual bolts. Finally, an updated design method is proposed that can accurately predict the bearing/tearout resistance of both austenitic and duplex stainless steel bolted connections. Proper partial factors are determined for the proposed method based on a reliability analysis.

由于不锈钢独特的材料特性，不锈钢螺栓连接的承载和撕裂行为可能与碳钢螺栓连接不同。这种差异在最近的不锈钢结构设计规定中已逐渐被认识到。但值得注意的是，现有的设计方法主要是针对奥氏体和铁素体不锈钢螺栓连接开发的。它们对双相不锈钢螺栓连接的适用性值得怀疑。此外，与不锈钢连接的轴承失效相比，对拆出失效以及多螺栓连接的轴承和拆出组合失效的关注较少。为了填补这些空白，对不锈钢螺栓连接的承载/撕裂性能和设计进行了试验和数值研究。试验方案包括22个连接试件，采用单螺栓或多螺栓配置，由奥氏体或双相不锈钢制成。实验测试是由一个全面的数值参数研究，超过200个单独的模型，基于验证的有限元建模技术进行的补充。利用试验结果和数值计算结果对不同设计参数的影响以及现有设计方法的适用性进行了评价。由此得出结论，奥氏体连接和双相连接的极限承载/抗撕裂性能并不简单地与两种材料的极限强度成正比。在相同的几何设计下，尽管两种材料的极限强度相似，但双相连接的承载阻力要比奥氏体连接高得多。这种承载性能的差异是由于奥氏体和双相材料的应变硬化特性不同，以及奥氏体连接中的过早剪切开裂导致应变硬化不充分发展。相比之下，具有相同几何形状的奥氏体和双相连接的抗撕裂性更接近，因为较小的端距导致更均匀的变形和更完全的应变硬化。此外，发现多螺栓连接的联合承载和撕裂阻力小于单个螺栓各自的阻力之和。最后，提出了一种更新的设计方法，可以准确预测奥氏体和双相不锈钢螺栓连接的承载/撕裂阻力。在可靠性分析的基础上，确定了该方法的适当偏因子。

Development of self-centring beam-to-column joints with large-dimensional SMA buckling-restrained plates

Zhi-Peng Chen, Songye Zhu

doi:10.1016/j.tws.2024.112586

大尺寸SMA抗屈曲板自定心梁柱节点的研制

This paper presents an innovative self-centring beam-to-column joint (SC-BCJ) design that utilises shape-memory alloy (SMA) plates. The proposed SMA-SC-BCJ is constructed through a straightforward approach using large-scale SMA plates to concentrate inelastic deformation and achieve self-centring (SC) capability. This paper first introduces the components and configuration of SMA-SC-BCJ, followed by the development of a refined finite element model for simulations. Validation against previous experiments verifies the model accuracy in capturing joint behaviour. The analysis shows SMA-SC-BCJ exhibits desirable flag-shaped hysteretic behaviours with excellent SC capability, achieving approximately 92% recovery alongside moderate energy dissipation. Substantial inelastic deformation localises in the SMA fuse plate due to joint rocking, with minimal plastic strain around the rocking centre. Parametric studies on shear element construction, bolt pretension levels and beam gap distances provide additional insights into the joint design. The proposed design meets the objectives for a minimal-damage beam-to-column joint with a simple construction. The SMA-SC-BCJ design recommendations are presented on the basis of performance assessments, elucidating the effectiveness of the system. This work contributes an innovative seismic-resistant joint solution that advances the emerging practices towards resilient structures.

本文提出了一种利用形状记忆合金（SMA）板的创新自中心梁柱节点（SC-BCJ）设计。所提出的SMA-SC- bcj是通过一种简单的方法构建的，使用大规模SMA板来集中非弹性变形并实现自定心（SC）能力。本文首先介绍了SMA-SC-BCJ的组成和结构，然后建立了精细化的有限元模型进行仿真。通过对先前实验的验证，验证了模型在捕获关节行为方面的准确性。分析表明，SMA-SC-BCJ具有良好的旗形滞回性能，具有优异的SC性能，在适度耗能的同时实现了约92%的恢复。大量的非弹性变形在SMA保险丝板局部由于接头的摇摆，与最小的塑性应变周围的摇摆中心。剪切单元结构、螺栓预紧水平和梁间隙距离的参数化研究为节点设计提供了额外的见解。提出的设计方案满足了梁柱节点损伤最小、结构简单的目标。在性能评估的基础上提出了SMA-SC-BCJ设计建议，阐明了系统的有效性。这项工作为创新的抗震接缝解决方案做出了贡献，推动了新兴的弹性结构实践。