今日更新：International Journal of Solids and Structures 1 篇，Journal of the Mechanics and Physics of Solids 3 篇，Mechanics of Materials 2 篇，Thin-Walled Structures 9 篇International Journal of Solids and StructuresAnalysis of shear shock waves in soft materials: From periodic elastic laminates and fibre-reinforced composites to molecular chain networksHannah Conroy Broderick, Stephan Rudykhdoi:10.1016/j.ijsolstr.2024.112790分析软材料中的剪切冲击波：从周期性弹性层压板和纤维增强复合材料到分子链网络We investigate the effect of microstructure and molecular length-scale structures on the formation of shear shock waves in soft materials. We consider (i) soft materials with layered microstructures, (ii) transversely isotropic fibre-reinforced composites (FC), as well as (iii) polymer chain networks, using homogenised energy density functions at the continuum scale. Critical conditions for the formation of shear shocks are found analytically for laminates and FCs, and are shown to depend only on the angle between the initial orientation direction and the applied load. We elucidate the effects of the microstructural material parameters on the shock formation distance. Our results show that increased stiffness ratio and volume fraction of fibres decreases the shock formation distance. The analysis of polymer-chain networks indicates that an increase in the entanglement increases the critical shock formation distance. We also highlight that by an appropriate choice of loading and material parameters, shock formation can be avoided, providing guidance for design of protective materials and structures.我们研究了微结构和分子长度尺度结构对软材料中剪切冲击波形成的影响。我们考虑了（i）具有层状微结构的软材料、（ii）横向各向同性纤维增强复合材料（FC）以及（iii）聚合物链网络，并使用了连续尺度的均质化能量密度函数。通过分析发现了层压板和 FC 形成剪切冲击的临界条件，并证明其仅取决于初始取向方向与施加载荷之间的角度。我们阐明了微结构材料参数对冲击形成距离的影响。结果表明，纤维的刚度比和体积分数增加会减小冲击形成距离。对聚合物链网络的分析表明，缠结度的增加会增加临界冲击形成距离。我们还强调，通过适当选择加载和材料参数，可以避免冲击形成，从而为保护材料和结构的设计提供指导。Journal of the Mechanics and Physics of SolidsCosserat-phase-field modeling of grain nucleation in plastically deformed single crystalsFlavien Ghiglione, Anna Ask, Kais Ammar, Benoît Appolaire, Samuel Forestdoi:10.1016/j.jmps.2024.105628塑性变形单晶中晶粒成核的科塞拉特相场模型Thermomechanical processing of crystalline materials induces microstructural evolution such as grain nucleation and growth. In the numerical simulation of these processes, grain nucleation is generally treated as an additional ad hoc step in which circular or spherical grains are added in regions where a critical dislocation density, stress or strain are reached. In this paper, systematic finite element simulations are performed showing that the Kobayashi-Warren-Carter (KWC) phase field model and its coupling with Cosserat crystal plasticity predict spontaneous nucleation of new grains in single crystals in the presence of lattice orientation/rotation gradients. The numerical analysis of the stability of gradients of lattice rotation and dislocation-based stored energy indicates that a gradient of stored energy alone is not sufficient to trigger grain formation. As an application, the KWC-Cosserat model is used to simulate the torsion and annealing of a copper single crystal bar with a circular cross section. This mechanical loading produces a large, fairly uniform axial rotation gradient which induces nucleation in the form of a stack of cylindrical grains. Plastic strain gradients in cross-sections predicted by the 3D finite element simulation, are not strong enough to compete with the longitudinal nucleation process, as confirmed by experimental observations from the literature.晶体材料的热机械加工会引起微结构演变，如晶粒成核和生长。在这些过程的数值模拟中，晶粒成核通常被视为一个额外的临时步骤，即在达到临界位错密度、应力或应变的区域添加圆形或球形晶粒。本文进行了系统的有限元模拟，结果表明小林-沃伦-卡特（KWC）相场模型及其与 Cosserat 晶体塑性的耦合可预测在晶格取向/旋转梯度存在的情况下单晶体中新晶粒的自发成核。对晶格旋转梯度和基于位错的储能稳定性的数值分析表明，仅靠储能梯度不足以引发晶粒形成。在应用中，KWC-Cosserat 模型被用来模拟横截面为圆形的铜单晶棒的扭转和退火。这种机械加载产生了较大且相当均匀的轴向旋转梯度，从而诱发了圆柱形晶粒堆积形式的晶核形成。三维有限元模拟预测的横截面塑性应变梯度不足以与纵向成核过程相抗衡，文献中的实验观察结果也证实了这一点。A local variational principle for fractureChristopher J. Larsendoi:10.1016/j.jmps.2024.105625断裂的局部变分原理The seminal paper of Francfort and Marigo (1998) introduced a variational formulation for Griffith fracture (Griffith, 1920) that has resulted in substantial theoretical and practical progress in modeling and simulating fracture. In particular, it led to the phase-field approximation proposed in Bourdin et al. (2000), which has been widely implemented. However, the formulation in Francfort and Marigo (1998) is known to have limitations, including its inability to treat applied loads and its reliance on global minimization. In addition, the phase-field model (Bourdin et al., 2000) and its extensions, as implemented, are not generally approximations of the global minimizers in Francfort and Marigo (1998). In this paper, we show that there is a local variational principle satisfied by global and local minimizers of the energy introduced in Francfort and Marigo (1998), which is compatible with loads, and which is a generalization of the stress intensity factor. We use this principle to reformulate variational fracture, including formulations that, for the first time, can include all forms of applied loads. We conclude by showing the connection between phase-field models, as implemented, and our formulations.Francfort 和 Marigo（1998 年）的开创性论文提出了格里菲斯断裂（格里菲斯，1920 年）的变分法，在断裂建模和模拟方面取得了重大的理论和实践进展。尤其是 Bourdin 等人（2000 年）提出的相场近似法，已得到广泛应用。然而，众所周知，Francfort 和 Marigo（1998 年）提出的方法有其局限性，包括无法处理外加载荷以及依赖于全局最小化。此外，相场模型（Bourdin 等人，2000 年）及其扩展模型，一般来说并不是 Francfort 和 Marigo（1998 年）中全局最小化模型的近似值。在本文中，我们展示了 Francfort 和 Marigo (1998) 中引入的能量的全局和局部最小化所满足的局部变分原理，该原理与负载兼容，是应力强度因子的广义化。我们利用这一原理重新表述变异断裂，包括首次包含所有外加载荷形式的表述。最后，我们将展示相场模型与我们的公式之间的联系。Kresling origami mechanics explained: Experiments and theoryShixi Zang, Diego Misseroni, Tuo Zhao, Glaucio H. Paulinodoi:10.1016/j.jmps.2024.105630克瑞林折纸力学解析：实验与理论From a kinematics perspective, a Kresling origami cell couples axial displacement (contraction/expansion) with twist, leading to non-rigid origami behavior. From an energy landscape perspective, the selection of the Kresling origami geometry, together with its fabrication process and material, lead to energy envelopes allowing single or multiple stable states. In this context, this paper explores the Kresling origami mechanics through mathematical modeling integrated with experimental testing. On the theoretical mechanics front, we present a comprehensive model incorporating the representative geometrical parameters of the Kresling origami cell into the corresponding energy function in order to capture its essential mechanical behavior. On the experimental mechanics front, we create two fixtures that demonstrate the ability to control axial displacement (contraction/expansion) and twist independently, without imposing any constraints on the chiral arrangement of individual cells within the Kresling origami array (composed of multiple cells). Finally, we show the coexistence of multiple mechanical and morphological configurations within the same Kresling array by programming its loading modes, i.e., compression or twist. The fundamental nature of this work makes it applicable to several field of engineering, including soft robotics and mechanical computing.从运动学的角度来看，克瑞斯林折纸单元将轴向位移（收缩/膨胀）与扭转结合在一起，导致了非刚性折纸行为。从能量分布的角度来看，克瑞斯林折纸几何形状的选择，加上其制造工艺和材料，会产生允许单一或多重稳定状态的能量包络。在此背景下，本文通过数学建模与实验测试相结合的方法探索克瑞斯林折纸力学。在理论力学方面，我们提出了一个综合模型，将克瑞斯林折纸电池的代表性几何参数纳入相应的能量函数，以捕捉其基本力学行为。在实验力学方面，我们制作了两个夹具，展示了独立控制轴向位移（收缩/膨胀）和扭转的能力，而不对克瑞斯林折纸阵列（由多个细胞组成）中单个细胞的手性排列施加任何限制。最后，我们展示了在同一个克瑞斯林阵列中，通过对其加载模式（即压缩或扭曲）进行编程，可实现多种机械和形态配置的共存。这项工作的基本性质使其适用于多个工程领域，包括软机器人和机械计算。Mechanics of MaterialsInterstitial fluid transport in cortical bone porosities: Effects of blood pressure and mass exchange using porous media theoryKasra Soleimani, Ahmad Ghasemloonia, Les Jozef Sudakdoi:10.1016/j.mechmat.2024.104981皮质骨孔隙中的间隙流体传输：利用多孔介质理论分析血压和质量交换的影响This research focuses on the importance of understanding bone adaptation for gaining insights into diseases such as osteoporosis. The study investigates the role of fluid flow in cortical bone adaptation, with a specific focus on the network of osteocyte canaliculi and the chemical reactions involved in bone resorption. Prior studies have implemented methods such as poroelasticity theory and dual porosity, but these models did not account for mass exchange between the solid and fluid phases within the bone or the pressure exerted by arteries. The movement of interstitial fluid between the vascular porosity and lacuno-canalicular porosity in cortical bone, as well as the velocity of the fluid, are affected by both the pressure exerted by arteries and the exchange of mass between the solid and fluid components of the bone. To incorporate these effects in the model, the authors propose a dual porosity model based on the theory of porous media. The model considers the transfer of mass between vascular and lacunar-canalicular porosities, as well as between solid and fluid phases, while also accounting for blood pressure variations. To verify the proposed model, a numerical example is solved and compared with the results of previous studies. The model enables the measurement and analysis of the interstitial fluid velocity and the pressure in the respective porosities. The results reveal that accounting for blood pressure pulses and mass exchange between solid and fluid phases can alter the velocity and pressure fields of interstitial fluid within cortical bone. In addition, this study investigates transient examples and various scenarios of the bone remodeling. Overall, this research provides a more accurate understanding of the bone remodeling and the effects of blood pressure variation and mass exchange between solid and fluid phases of cortical bone.这项研究的重点是了解骨适应对深入了解骨质疏松症等疾病的重要性。研究调查了流体流动在皮质骨适应性中的作用，特别关注骨细胞管网和骨吸收过程中的化学反应。之前的研究采用了孔弹性理论和双孔隙率等方法，但这些模型没有考虑骨内固相和液相之间的质量交换或动脉施加的压力。皮质骨中的血管孔隙和裂隙-钙质孔隙之间的间隙流体运动以及流体的速度都会受到动脉施加的压力以及骨中固态和液态成分之间的质量交换的影响。为了将这些影响纳入模型，作者根据多孔介质理论提出了双孔模型。该模型考虑了血管孔隙和裂隙-椎管孔隙之间以及固相和流体相之间的质量转移，同时还考虑了血压变化。为了验证所提出的模型，对一个数值示例进行了求解，并与之前的研究结果进行了比较。该模型可以测量和分析间质流体的速度和各孔隙中的压力。结果表明，考虑到血压脉冲以及固相和流体相之间的质量交换，可以改变皮质骨内间隙流体的速度场和压力场。此外，这项研究还调查了骨重塑的瞬态示例和各种情况。总之，这项研究能让人们更准确地理解骨重塑以及皮质骨中血压变化和固相与流体相之间质量交换的影响。Thermomechanical response and elastocaloric effect of shape memory alloy wiresLonghuan Tian, Jianyou Zhou, Pan Jia, Zheng Zhongdoi:10.1016/j.mechmat.2024.104985形状记忆合金丝的热机械响应和弹性效应Refrigeration technologies based on the elastocaloric effect of shape memory alloys (SMAs) have attracted much interest in recent years. To seek for schemes that can improve the temperature span and efficiency of elastocaloric devices, this work explores more practical loading conditions (between adiabatic and isothermal) of SMAs. To account for the smoothness of the martensite phase transformation of SMAs, a general polynomial form of hardening-like function is adopted in the phenomenological multi-physics coupling framework. The modeling framework is further calibrated by measurements of the thermomechanical responses of pre-trained Ni–Ti wires. Due the hardening-like function, the martensitic volume fraction cannot be explicitly expressed. Accordingly, a new numerical scheme is also presented in this work. Moreover, an empirical function of the maximum transformation strain is proposed based on the experimental observation, which improves the capability of the model to capture experimental data. This work aims to provide a paradigm from material characterization to theoretical modeling and numerical simulation, and then to elastocaloric cooling performance analysis of SMAs.基于形状记忆合金（SMA）弹性热效应的制冷技术近年来备受关注。为了寻求能提高弹性热效应设备的温度跨度和效率的方案，这项研究探索了更实用的 SMA 加载条件（介于绝热和等温之间）。为了解释 SMA 马氏体相变的平滑性，在现象学多物理场耦合框架中采用了一般多项式形式的类硬化函数。通过测量预训练镍钛丝的热机械响应，进一步校准了建模框架。由于采用了类硬化函数，马氏体体积分数无法明确表达。因此，本研究还提出了一种新的数值方案。此外，还根据实验观察结果提出了最大转变应变的经验函数，从而提高了模型捕捉实验数据的能力。这项工作旨在提供一个从材料表征到理论建模和数值模拟，再到 SMA 弹性冷却性能分析的范例。Thin-Walled StructuresDynamic responses of concrete-filled steel tubes impacted horizontally by a rigid vehicle: Experimental study and numerical modellingShuhong LIN, Bing ZHANG, Sumei ZHANG, Yijie ZHANG, Xiamin HUdoi:10.1016/j.tws.2024.111826刚性车辆水平撞击混凝土填充钢管的动态响应：实验研究和数值模拟Concrete-filled steel tubes (CFSTs), composed of an outer tube made of steel as the confining material and an inner concrete core, have been popularly utilized as high-rise building columns and urban bridge piers owing to their superior structural behavior. Since the invention of CFSTs, their mechanical performance under static and seismic loading conditions have been extensively studied, while the investigation on their dynamic behavior under impact loading is relatively limited. Of these limited studies about CFSTs under impact loading conditions, most experiments were completed using a drop-hammer testing facility or a pendulum-hammer testing device. Against this background, this study investigated six large CFSTs being impacted horizontally by a rigid vehicle to analysis their dynamic response. All specimens were vertically placed with the bottom pedestal fixed on the lab floor and the top end free. The main parameters of these CFSTs included the impact velocity (i.e., vi = 3.16 ∼ 7.18 m/s), the CFST section size (i.e., D = 180 ∼ 300 mm), as well as the CFST column height (i.e., hc = 1500 ∼ 2100 mm). Test results revealed that, (1) all CFSTs experienced a bending-dominant failure when impacted horizontally by a rigid vehicle; (2) the impact velocity had a positive correlative trend with the peak impact force F_peak and the peak lateral displacement δ_peak of the CFST column; (3) a larger section size of the CFST column resulted in a higher flexural stiffness and a larger flexural capacity, thus leading to a higher F_peak, a smaller time duration T and a smaller δ_peak; (4) the column height would affect the inertial response of the CFST column; a larger column height led to a larger F_peak caused by the larger inertia effect of the CFST segment above the impact point. Finite-element model was established on the platform of LS-DYNA to simulate these CFSTs under horizontal impact loading, which was able to predict both impact force-time history curves and lateral displacement-time history curves with reasonably accuracy.混凝土填充钢管（CFST）由钢制外管和混凝土内芯组成，由于其优异的结构性能，已被广泛用作高层建筑的支柱和城市桥梁的桥墩。自 CFST 发明以来，人们对其在静态和地震荷载条件下的力学性能进行了广泛的研究，而对其在冲击荷载下的动态行为的研究则相对有限。在这些有限的关于 CFST 在冲击荷载条件下的研究中，大多数实验都是使用落锤试验设备或摆锤试验装置完成的。在此背景下，本研究调查了六种大型 CFST 受刚性车辆水平冲击的情况，以分析其动态响应。所有试样均垂直放置，底座固定在实验室地板上，上端自由。这些 CFST 的主要参数包括冲击速度（即 vi = 3.16 ∼ 7.18 m/s）、CFST 截面尺寸（即 D = 180 ∼ 300 mm）以及 CFST 柱高（即 hc = 1500 ∼ 2100 mm）。试验结果表明：(1) 所有 CFST 在受到刚性车辆水平撞击时都会发生以弯曲为主的破坏；(2) 撞击速度与 CFST 柱的峰值撞击力 F_peak 和峰值横向位移 δ_peak 呈正相关趋势； (3) CFST 柱的截面尺寸越大，抗弯刚度越大，抗弯能力越强，因此 F_peak 值越大，持续时间 T 越小，δ_peak 值越小；(4) 柱高会影响 CFST 柱的惯性响应；柱高越大，F_peak 值越大，这是由于冲击点上方的 CFST 段具有较大的惯性效应。在 LS-DYNA 平台上建立了有限元模型来模拟这些 CFST 在水平冲击荷载下的响应，该模型能够合理准确地预测冲击力-时间历史曲线和侧向位移-时间历史曲线。Ballistic performance of thin CFRP lamindisatediss under complex in-plane preloadShijia Xu, Shuhan Zhou, Beiyao Xiao, Naihang Kuang, Gang Wei, Wei Zhangdoi:10.1016/j.tws.2024.111829 薄 CFRP 片材在复杂面内预紧力作用下的弹道性能In this research, we explore the effects of complex in-plane quasi-static loads on the high-velocity impact response of Carbon Fiber Reinforced Plastic (CFRP) composite laminates, grounded in the practical context of various working loads combined with potential high-velocity impacts experienced by aircraft. The specific complex in-plane loads studied include uniaxial tension and compression, biaxial tension and compression, and a combination of tension and compression preloading. The results show that the complexity of in-plane preloads, along with pre-compression, reduces the ballistic limit velocity. Biaxial preloading, especially in compression, greatly compromises the specimen's ballistic resistance. The study also proposes a theoretical model based on energy conservation principles to predict the ballistic limit velocity of CFRP laminates under various preloading conditions. The research provides valuable insights for designing composite structures and highlights the importance of considering in-plane preloads in assessing thin CFRP ability to withstand ballistic impacts.在这项研究中，我们以飞机所经历的各种工作载荷与潜在高速撞击的实际情况为基础，探讨了复杂面内准静态载荷对碳纤维增强塑料（CFRP）复合材料层压板高速撞击响应的影响。研究的具体复杂面内载荷包括单轴拉伸和压缩、双轴拉伸和压缩以及拉伸和压缩预加载组合。结果表明，平面内预紧力的复杂性以及预压缩会降低弹道极限速度。双轴预加载，尤其是压缩预加载，会大大降低试样的抗弹性。研究还提出了一个基于能量守恒原理的理论模型，用于预测各种预加载条件下 CFRP 层压板的弹道极限速度。该研究为设计复合材料结构提供了宝贵的见解，并强调了在评估薄 CFRP 承受弹道冲击能力时考虑面内预载的重要性。Unified machine-learning-based design method of normal and high strength steel I-section beam–columnsAndi Su, Jinpeng Cheng, Xuelai Li, Yukai Zhong, Shuai Li, Ou Zhao, Ke Jiangdoi:10.1016/j.tws.2024.111835基于机器学习的普通和高强度工字钢梁柱统一设计方法High strength steel is regarded as a promising construction material due to its superior mechanical properties. However, the codified failure load predictions for high strength steel welded I-section beam–columns are not accurate in some cases owing to the lack of relevant design codes for high strength steel structures. In addition, current design codes ignore the interaction effect of the cross-section plate elements, leading to the inaccuracy of codified predictive ultimate resistances for both normal and high strength steel beam–columns. In this paper, a unified and accurate design method was proposed based on machine learning for both normal and high strength steel welded I-section beam–columns failing by different failure modes. Firstly, a total of 812 experimental and numerical data on welded I-section beam–columns with various steel grades, geometric dimensions, including cross-section dimensions and member lengths, and failure modes, including global buckling, local buckling and local–global interactive buckling were collected to establish a database. Seven machine learning algorithms, including Decision Tree, Random Forest, Support Vector Machine, K-Nearest Neighbour, Adaptive Boosting, Extreme Gradient Boosting and Categorical Boosting were applied to develop regression models to predict failure loads. Based on the established database, each machine learning model was then trained and key hyperparameters were optimised. The model performance was evaluated through a series of statistical indicators and the feature importance analysis, and the evaluated results indicated that the XG-trained regression model had the highest level of accuracy. Finally, the predictions given by the XG-trained regression model were compared with those of the existing codified design provisions, as given in Eurocode and American codes. The evaluation results indicated that the codified predictive bearing capacities of I-section beam–columns were scattered and inaccurate, while the XG-trained regression model provided substantially improved failure load predictions.高强度钢因其优越的机械性能而被视为一种前景广阔的建筑材料。然而，由于缺乏相关的高强度钢结构设计规范，在某些情况下，对高强度钢焊接工字钢梁柱的破坏荷载进行的规范化预测并不准确。此外，现行设计规范忽略了截面板元素的相互作用效应，导致普通钢梁柱和高强度钢梁柱的编纂极限抗力预测不准确。本文提出了一种基于机器学习的统一而精确的设计方法，适用于以不同破坏模式破坏的普通和高强度钢焊接工字形梁柱。首先，收集了不同钢种、几何尺寸（包括截面尺寸和构件长度）和失效模式（包括全局屈曲、局部屈曲和局部-全局交互屈曲）的焊接工字钢梁柱的 812 个实验和数值数据，建立了数据库。应用七种机器学习算法（包括决策树、随机森林、支持向量机、K-近邻、自适应提升、极梯度提升和分类提升）来开发预测失效载荷的回归模型。在已建立的数据库基础上，对每个机器学习模型进行了训练，并对关键超参数进行了优化。通过一系列统计指标和特征重要性分析对模型性能进行了评估，评估结果表明，XG 训练的回归模型具有最高的准确性。最后，将 XG 训练回归模型给出的预测结果与欧洲规范和美国规范中现有的成文设计规定进行了比较。评估结果表明，规范中对工字节梁柱承载力的预测是分散和不准确的，而 XG 训练回归模型提供的破坏荷载预测则有很大改进。Multiscale modeling for fatigue crack propagation of notched laminates using the UMAP clustering algorithmDanhui Yang, Mingze Ma, Viska Wei, Jianping Li, Jin Zhou, Xinyi Song, Zhongwei Guan, Xuefeng Chendoi:10.1016/j.tws.2024.111819利用 UMAP 聚类算法对缺口层压板的疲劳裂纹扩展进行多尺度建模In this study, a novel multiscale fatigue-damage model was developed based on the parametric finite-volume direct-averaging micromechanics theory (FVDAM), the uniform manifold approximation and projection (UMAP) algorithm, and the extended finite element method (XFEM) to accurately portray the progressive propagation of fatigue cracks in notched laminates. The UMAP clustering technique was integrated with fatigue damage evolution for the first time, enabling the construction of a reduced-order unit cell with fatigue information. Compared with the conventional FVDAM unit cell, the data was reduced to 0.4% of its original size, significantly accelerating fatigue damage calculations. The reduced-order unit cell was then incorporated into XFEM, functions as the fatigue damage criterion, transmitting fatigue damage information to meso- and macro-scales, and enables fatigue crack simulation in notched laminates. To further accelerate the calculation, a cycle-jump scheme was integrated, resulting in computational time being 10 times shorter compared to cycle-by-cycle simulation while maintaining accuracy. To validate the effectiveness of the proposed model, experiments of notched [ ±60]7s glass-fibre/epoxy laminates under three different fatigue loads were conducted. The simulation results of all three loads were within a scatter band of factor two, which was a good accuracy in fatigue, showing the effectiveness of the proposed model.本研究基于参数化有限体积直接平均微观力学理论（FVDAM）、均匀流形近似和投影算法（UMAP）以及扩展有限元法（XFEM），建立了一种新型多尺度疲劳损伤模型，以准确描述缺口层板中疲劳裂纹的逐渐扩展过程。UMAP 聚类技术首次与疲劳损伤演化相结合，从而构建了包含疲劳信息的降阶单元。与传统的 FVDAM 单元相比，数据量减少到原来的 0.4%，大大加快了疲劳损伤计算速度。然后，将缩减阶单元纳入 XFEM，作为疲劳损伤准则，将疲劳损伤信息传递到中观和宏观尺度，实现了缺口层板的疲劳裂纹模拟。为了进一步加快计算速度，还集成了循环跳转方案，在保持精度的前提下，计算时间比逐个循环模拟缩短了 10 倍。为了验证所提模型的有效性，对三种不同疲劳载荷下的缺口[ ±60]7s 玻璃纤维/环氧树脂层压板进行了实验。三种载荷的模拟结果都在因数 2 的散布带内，这在疲劳中是一个很好的精度，显示了所提模型的有效性。Experimental and theoretical study on mechanical performance of Fe-SMA/steel single lap jointsYue Shu, Xuhong Qiang, Xu Jiang, Yuepeng Lidoi:10.1016/j.tws.2024.111824铁-SMA/钢单搭接接头机械性能的实验和理论研究The activated iron-based shape memory alloy (Fe-SMA) can introduce considerable prestress in the damaged zone of deteriorated steel structures through bonding technologies. In China, it has been successfully applied to several kilometer-span steel bridges, such as Sutong Bridge and Hangzhou Bay Bridge. The shear and interfacial performance of steel-to-Fe-SMA plates are crucial issues in bonding Fe-SMA to reinforce deteriorated steel structures, which remain unclear. This paper investigates the shear characteristics of Fe-SMA/steel single lap joints (SLJs), considering the effects of adhesive types, adhesive layer thicknesses and overlap lengths. The stress distribution and the interfacial shear stress at the overlap zone are obtained through experiments, and the damage evolution and load-transfer mechanisms of adhesive layers are analyzed. The experimental outcomes indicate that the maximum tensile stresses of Fe-SMA plates can reach 61 % of their ultimate strength. The failure modes and ultimate load of Fe-SMA/steel SLJs are affected by adhesive types. Interface failure occurs in CH 120 and PCMdur™-15 specimens, whereas interface, cohesive and mixing failure are formed in Sika 31 specimens. Due to the adverse effects of adhesive layer defects, out-of-plane bending moment, and damage accumulation of the adhesive layers, the distribution of surface strain and interfacial shear stress of all specimens are mainly at the effective overlap zone. For an efficient engineering design, the linear and polynomial fitting models of cohesive zone models with different adhesive types and adhesive layer thicknesses are proposed based on experiments. The experimental and theoretical achievements can provide design recommendations for deteriorated steel structures rehabilitated by bonding Fe-SMA.活化铁基形状记忆合金（Fe-SMA）可通过粘结技术在劣化钢结构的损坏区引入相当大的预应力。在中国，该技术已成功应用于苏通大桥、杭州湾跨海大桥等多座跨度达千米的钢结构桥梁。钢-Fe-SMA 板的剪切性能和界面性能是粘结 Fe-SMA 以加固劣化钢结构的关键问题，目前仍不清楚。本文研究了铁-SMA/钢单搭接接头（SLJ）的剪切特性，考虑了粘合剂类型、粘合剂层厚度和搭接长度的影响。通过实验获得了重叠区的应力分布和界面剪应力，并分析了粘合剂层的损伤演变和载荷传递机制。实验结果表明，Fe-SMA 板的最大拉伸应力可达其极限强度的 61%。铁-SMA/钢 SLJ 的破坏模式和极限载荷受粘合剂类型的影响。CH 120 和 PCMdur™-15 试样会出现界面破坏，而 Sika 31 试样则会出现界面、内聚和混合破坏。由于粘合剂层缺陷、平面外弯矩和粘合剂层损伤累积的不利影响，所有试样的表面应变和界面剪应力主要分布在有效重叠区。为了有效地进行工程设计，在实验的基础上提出了不同粘合剂类型和粘合剂层厚度的内聚区模型的线性拟合模型和多项式拟合模型。这些实验和理论成果可为通过粘接 Fe-SMA 修复破损钢结构提供设计建议。Estimating welding deformation of ultra-thin mild steel bead-on-plate joints by means of inherent strain methodWei Liang, Zhixu Mao, Long Hu, Dean Dengdoi:10.1016/j.tws.2024.111825用固有应变法估算超薄低碳钢焊珠与钢板连接处的焊接变形The inherent strain method as an efficient computational tool has been widely used to predict welding deformation for large and complex structures with thin and medium-thick plates. For ultra-thin plate welded structures, geometric non-linear phenomena often arise during welding because of the low stiffness. In this study, the welding deformation of 0.8 mm thick bead-on-plate mild steel joints was studied by both experimental method and thermal-elastic-plastic finite element method (T-E-P FEM), and the influences of weld lengths on Tendon force, transverse shrinkage and angular distortion were examined experimentally and numerically. Meanwhile, a non-linear elastic finite element method based on the inherent strain theory using ABAQUS software as a platform was developed to reproduce the welding deformation of the ultra-thin bead-on-plate joints with different weld lengths, and the adaptability of the inherent strain method to ultra-thin plate weldments was clarified.固有应变法作为一种高效的计算工具，已被广泛用于预测大型复杂结构中薄板和中厚板的焊接变形。对于超薄板焊接结构，由于刚度较低，在焊接过程中往往会出现几何非线性现象。本研究采用实验法和热-弹-塑有限元法（T-E-P FEM）研究了 0.8 毫米厚的钢珠-钢板低碳钢接头的焊接变形，并通过实验和数值分析了焊缝长度对拉伸力、横向收缩和角变形的影响。同时，以 ABAQUS 软件为平台，开发了基于固有应变理论的非线性弹性有限元方法，再现了不同焊缝长度的超薄珠对板接头的焊接变形，明确了固有应变方法对超薄板焊接的适应性。Manufacturing of curved profiles using an extrusion-bending continuous forming processLiang Xu, Yongsheng Pei, Zhiwen Liu, Cong Gao, Pengfei Xie, Congchang Xu, Luoxing Lidoi:10.1016/j.tws.2024.111831利用挤压弯曲连续成型工艺制造弯曲型材An extrusion-bending continuous forming process (EBCFP) is proposed for manufacturing curved profiles, which enables online bending of the extruded profiles at the die outlet with the guide of a robotic arm. Experimental setups were designed and constructed. Extrusion-bending experiments were conducted using AA6063 aluminum alloy under different process parameters. The Springback, cross-section deformation, microstructure, and mechanical properties of the extruded-bent profiles were investigated. Compared to conventional stretch-bent profiles, the extruded-bent profiles exhibit reduced springback and cross-sectional deformation and higher mechanical properties.提出了一种用于制造曲面型材的挤压弯曲连续成型工艺（EBCFP），该工艺可在机械臂的引导下在模具出口处对挤压型材进行在线弯曲。实验装置已设计完成。使用 AA6063 铝合金在不同工艺参数下进行了挤压弯曲实验。研究了挤压弯曲型材的回弹、截面变形、微观结构和机械性能。与传统的拉伸弯曲型材相比，挤压弯曲型材的回弹和截面变形更小，力学性能更高。Advanced virtual modelling aided stochastic nonlinear dynamic stability analysis of the GPLR-FGP plate in thermal environmentsLuo Bo, Jize Zhang, Huiying Wangdoi:10.1016/j.tws.2024.111833 热环境中 GPLR-FGP 板的高级虚拟建模辅助随机非线性动态稳定性分析This paper explores the crucial yet challenging task of stochastic nonlinear dynamic buckling investigations of the GPLR-FGP plate under biaxial impacts in thermal environments with multi-dimensional uncertainties for the first time. An advanced virtual modelling technique, namely the Extended Support Vector Regression (XSVR) with a fresh S-spline polynomial kernel, is newly developed to alternatively depict the underpinned and sophisticated relationship between the inevitable system uncertainties and concerned nonlinear buckling response in an efficient fashion. Adequate statistical information of stability performance is furnished for the safety assessment and reliability-based design of the GPLR-FGP composite. The superior competence, advisable exactness, and appealing efficiency of the proposed uncertainty quantification framework are vividly demonstrated through benchmark tests and comprehensive numerical experiments against established machine learning algorithms. Moreover, the user-friendly modularity feature, and unique capabilities of expeditious information update and responsiveness highlight the versatile applicability of the proposed technique in realistic structural implementation under swiftly changing environments.本文首次探讨了在多维不确定性的热环境中对双轴冲击下的 GPLR-FGP 板进行随机非线性动态屈曲研究这一关键而又具有挑战性的任务。我们新开发了一种先进的虚拟建模技术，即带有全新 S-样条多项式内核的扩展支持向量回归（XSVR），以另一种高效的方式描述不可避免的系统不确定性与相关非线性屈曲响应之间的复杂关系。为 GPLR-FGP 复合材料的安全评估和可靠性设计提供了充分的稳定性能统计信息。通过基准测试和全面的数值实验，对照已有的机器学习算法，生动地展示了所提出的不确定性量化框架的卓越能力、可取的精确性和极具吸引力的效率。此外，该技术还具有用户友好的模块化特点，以及快速更新信息和响应的独特能力，这一切都凸显了该技术在瞬息万变的环境下，在现实结构实施中的广泛适用性。Investigation of FGM membrane wrinkling using reduced models based on a multi-scale methodSiham Khalil, Oussama Elmhaia, Bouazza Braikat, Abdellah Hamdaoui, Heng Hu, Adnane Boukamel, Noureddine Damildoi:10.1016/j.tws.2024.111834使用基于多尺度方法的简化模型研究 FGM 膜起皱问题In this article, we show that the reduced model proposed in our recent article to study the wrinkling of homogeneous elastic membranes does not reproduce the wrinkling observed in the case of an FGM-type composite membrane. New reduced models are then proposed to investigate the wrinkling of membranes made from Functionally Graded Materials (FGM). We examine, by this way, the influence of material functional parameters on determining the critical load and post-critical behavior under different loads. These reduced models, created using a multi-scale method based on Fourier series with slowly varying coefficients, enrich the reference model. In addition, these reduced models also allow us to significantly decrease the computation time and the number of finite elements compared to the complete model. The robustness of these reduced models is demonstrated in the case of wrinkling of membranes modeled by very thin shells, which are discretized using DKT18-type finite elements as described in literature. The resulting nonlinear problems are solved using a High-Order Continuation Method (HOCM).在这篇文章中，我们证明了在我们最近的文章中提出的用于研究均质弹性膜起皱的简化模型不能再现在 FGM 型复合膜中观察到的起皱现象。因此，我们提出了新的简化模型来研究由功能分级材料（FGM）制成的膜的起皱问题。通过这种方法，我们研究了材料功能参数对确定不同载荷下的临界载荷和临界后行为的影响。这些简化模型是基于系数缓慢变化的傅里叶级数的多尺度方法创建的，丰富了参考模型。此外，与完整模型相比，这些简化模型还能大大减少计算时间和有限元数量。这些简化模型的稳健性在以极薄的壳为模型的膜起皱案例中得到了证明，这些极薄的壳使用文献中描述的 DKT18 型有限元进行离散化。由此产生的非线性问题采用高阶连续法 (HOCM) 进行求解。来源：复合材料力学仿真Composites FEM
