【新文速递】2024年9月12日复合材料SCI期刊最新文章_ACT_Mechanical_Additive_System_Inspire_断裂_复合材料_燃烧_化学_电子_铸造_离散元_裂纹_理论_材料_太阳能

【新文速递】2024年7月30日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Journal of the Mechanics and Physics of Solids 1 篇，Thin-Walled Structures 3 篇International Journal of Solids and StructuresControlling screw dislocation core structure and Peierls barrier in BCC interatomic potentialsZachary H. Aitken, Viacheslav Sorkin, Zhi Gen Yu, Shuai Chen, Teck Leong Tan, Zhaoxuan Wu, Yong-Wei Zhangdoi:10.1016/j.ijsolstr.2024.113004 BCC原子间势中螺位错核结构和peerls势垒的控制For screw dislocations in BCC metals, three mysteries have persisted, that is, compact vs degenerate core structure, single-hump vs double-hump Peierls barrier, and the relation between the core structure and Peierls barrier. We discover that the compact core consists of atoms in a FCC stacking sequence and that the degenerate core consists of atoms in a HCP stacking sequence, suggesting that BCC, FCC, and HCP must be considered to correctly capture the core structure. Informed by a machine learning model, we can generate interatomic potentials that reliably predict a compact core structure. We further show the compact core structure does not necessarily lead to the single-hump Peierls barrier.对于BCC金属的螺位错，存在紧致与简并核结构、单驼峰与双驼峰Peierls势垒以及核心结构与Peierls势垒之间的关系三个未解之谜。我们发现致密核由FCC堆叠顺序的原子组成，简并核由HCP堆叠顺序的原子组成，这表明必须考虑BCC, FCC和HCP才能正确捕获核心结构。通过机器学习模型，我们可以生成原子间电位，可靠地预测紧凑的核心结构。我们进一步证明，致密的核心结构并不一定导致单峰佩尔斯势垒。Journal of the Mechanics and Physics of SolidsTowards stable End Notched Flexure (ENF) testsXiaole Li, Gilles Lubineaudoi:10.1016/j.jmps.2024.105795走向稳定的端缺口弯曲(ENF)测试Mode II fracture toughness of interfaces in laminated structures is usually assessed through standardized tests. Standards are based on samples featuring regular shapes and uniform cross-sections, in which mode II propagation happens to be unstable. We explore here, via a semi-analytical approach, the potential of more complex geometry and shapes for stabilizing the crack propagation. Results demonstrate that an end-notch flexure (ENF) sample with increasing width along the propagation direction possesses a more stable fracture compared to the classical configuration. This leads to the conceptualization of a width-tapered ENF (WTENF) that can address the instability issue encountered by the classical ENF samples. The closed-form solution of WTENF is derived, including the compliance and energy release rate of the system, based on which, the stability status diagram of WTENF has been provided. A systematic validation is performed by numerical and physical experiments, confirming the validity and the accuracy of the associated data reduction model. The WTENF can be a robust method with enhanced stability for measuring the mode II delamination toughness. Beyond solving the WTENF, the derived equations hold significant potential for other applications, such as probing the length-scale effect for delamination of fiber-reinforced composites and guiding the design of toughening strategies for interfaces.层合结构界面II型断裂韧性通常通过标准化试验来评估。标准是基于具有规则形状和均匀截面的样品，其中II型传播恰好是不稳定的。我们在这里通过半解析的方法探索更复杂的几何形状和形状对稳定裂纹扩展的潜力。结果表明，与经典结构相比，端缺口弯曲(ENF)试样沿扩展方向宽度增大时具有更稳定的断裂。这导致了宽度锥形ENF (WTENF)的概念化，它可以解决经典ENF样本遇到的不稳定性问题。推导了WTENF的闭式解，包括系统的柔度和能量释放率，并在此基础上给出了WTENF的稳定状态图。通过数值和物理实验进行了系统验证，验证了相关数据约简模型的有效性和准确性。WTENF是测量II型分层韧性的一种稳定可靠的方法。除了求解WTENF外，导出的方程在其他应用中也具有重要的潜力，例如探测纤维增强复合材料分层的长度尺度效应，以及指导界面增韧策略的设计。Thin-Walled StructuresInterference effect on super large twin cooling towers exposed to stationary tornado-like vorticesXu Dong, Lin Zhao, Xu Chen, Degang Peng, Xiang Ren, Mao Chen, Shuyang Cao, Yaojun Gedoi:10.1016/j.tws.2024.112262超大型双冷却塔暴露在静止的类龙卷风涡旋中的干扰效应A comprehensive investigation was conducted aiming at the interference effects on wind pressure distribution, aerodynamics characteristics, structural stability and reinforcement areas of super large twin cooling towers exposed to tornado-like vortices, and the effects of swirl ratios of tornados, grouped tower layouts, and relative central distances between the towers and the tornado were analysed based on a tornado-like vortex simulator. Two types of rigid model wind tunnel experiments were constructed for base forces and wind pressure distribution measurements. The experimental results demonstrate that the interference effects on base forces and local wind pressures are significantly influenced by the swirl ratios, central distances, and grouped tower layouts, etc. Moreover, the layout with a tornado located on the side of tandem twin cooling towers (along with the tornado translation direction being perpendicular to the central axis of the tandem combined twin cooling towers) is the most unfavourable, resulting in obvious amplification effects on base forces and local wind pressures compared with an isolated tower, and the maximum of interference factors (IFs) is 1.68 and 1.41 for the along-wind total wind force coefficient and minimal net mean pressure coefficient respectively. Subsequently, local stability indices and time-variant dynamic reinforcement envelopes were selected as the other evaluation criteria for estimating the interference effects on the cooling towers exposed to the tornado-like vortices, and the interference effects result in enlargements of the structural responses with the maximal IF of 1.36 for the inside meridional reinforcement. Finally, the various interference criteria at aerodynamic loading and structural reinforcement aspects were contrastive analysed, showing that the criterion of time-variant dynamic reinforcement area envelopes is a more reasonable criterion for evaluating the interference effects on the super large cooling towers exposed to the tornado-like vortices. This investigation aims to contribute to a better understanding of the wind-related effects of the cooling towers exposed to extreme non-synoptic winds, particularly tornadic vortex impacts.基于类龙卷风涡模拟器，对超大双冷却塔在类龙卷风涡作用下的风压分布、空气动力学特性、结构稳定性和加固面积的干扰影响进行了全面研究，分析了龙卷风旋流比、塔群布局、塔与龙卷风相对中心距离等因素的影响。建立了两种刚性模型风洞试验，进行了基础力和风压分布测量。实验结果表明，旋涡比、中心距离和塔群布局等因素对基力和局地风压的干扰效应有显著影响。其中，位于串联双冷却塔侧面的龙卷风布局(且龙卷风平移方向垂直于串联双冷却塔中心轴线)最为不利，与孤立塔相比，对基地力和局部风压的放大效应明显。沿风总风力系数和最小净平均压力系数的干扰因子最大值分别为1.68和1.41。在此基础上，选取局部稳定性指标和时变动力加固包络线作为评价龙卷风涡作用下冷却塔干扰效应的评判标准，干涉效应导致结构响应增大，其中经向内加固的IF值最大，达到1.36。最后，对气动载荷和结构加固方面的各种干扰判据进行了对比分析，表明时变动力加固面积包络判据是评价超大冷却塔在龙卷风涡作用下的干扰效果更为合理的判据。这项调查的目的是为了更好地了解冷却塔在极端非天气风，特别是龙卷风涡旋影响下与风有关的影响。Hysteretic behavior optimization of hollow laminated viscoelastomer-filled steel tube damperJiale Li, Yun Zhou, Chenghao Shang, Feng Zhaodoi:10.1016/j.tws.2024.112277空心粘弹性体夹层钢管阻尼器滞回性能优化This study proposes a shape optimization approach for designing hollow laminated viscoelastomer-filled steel tube dampers (HLVSTDs), aiming to reduce stress concentration, enhance energy dissipation capacity, and improve low-cycle fatigue performance. The shape optimization curve is obtained based on the definition of stress contours for HLVSTD bending moments and shear forces, with the assumption that points on the same contour yield simultaneously. Cyclic loading experiments were conducted on four HLVSTDs. Numerical models were established and validated to further investigate the mechanical properties, energy dissipation capacity, and seismic performance of the shape-optimized HLVSTDs. The results demonstrate that the shape-optimized HLVSTDs specimen exhibits excellent energy dissipation capacity and improved low-cycle fatigue performance. The calculated initial stiffness and yield force closely align with experimental values. Compared to non-optimized HLVSTDs, the shape-optimized HLVSTDs exhibit more uniform stress and equivalent plastic strain distributions, effectively reducing the concentration of plastic strains. Additionally, structures equipped with shape-optimized HLVSTDs demonstrate superior seismic performance.本文提出了一种中空粘弹性体填充钢管层合阻尼器(HLVSTDs)的形状优化设计方法，旨在降低应力集中，增强消能能力，提高低周疲劳性能。基于HLVSTD弯矩和剪力应力轮廓的定义，假设同一轮廓上的点同时屈服，得到形状优化曲线。在4个高强度钢板上进行了循环加载试验。建立并验证了数值模型，进一步研究了形状优化后的HLVSTDs的力学性能、耗能能力和抗震性能。结果表明:优化后的HLVSTDs试样具有良好的耗能能力和较好的低周疲劳性能。计算的初始刚度和屈服力与实验值吻合较好。与未优化的HLVSTDs相比，形状优化的HLVSTDs具有更均匀的应力和等效塑性应变分布，有效降低了塑性应变的浓度。此外，配备形状优化的HLVSTDs的结构具有优越的抗震性能。Bayesian Optimization-based Model-Agnostic Meta-Learning: Application to Predict Maximum Cyclic Moment Resistance of Steel Bolted T-stub ConnectionsYanfei Shen, Mao Li, Yong Lidoi:10.1016/j.tws.2024.112279基于贝叶斯优化的模型不可知元学习:用于预测t型螺栓连接的最大循环弯矩阻力Accurately assessing the maximum moment resistance of steel bolted T-stub connections under cyclic loading is crucial for designing earthquake-resistant structures with such connections. Traditional methods based on design standards like ASCE 41-17 often lack precision. Recently, supervised machine learning techniques, particularly Artificial Neural Network (ANN), have been explored. However, conventional ANNs require substantial data for generalization, which is limited for steel bolted T-stub connections. To address these challenges, this study explores the feasibility of using the Model-Agnostic Meta-Learning (MAML) to predict the maximum cyclic moment resistance of steel bolted T-stub connections. MAML adapts task-specific model parameters rapidly and transfers knowledge across tasks to fine-tune global model parameters, potentially enhancing prediction accuracy with limited data. The MAML model is first optimized using Bayesian optimization with a Gaussian Process model to identify ideal hyperparameters. The optimized MAML model is then compared with two ANN models (one with optimized hyperparameters, another matching MAML's neural network architecture) and ASCE 41-17 method. Results demonstrate the optimized MAML model's superior generalization capabilities, offering a promising approach for steel bolted T-stub connections.准确评估t型连接在循环荷载作用下的最大抗弯矩能力，是设计t型连接抗震结构的关键。基于ASCE 41-17等设计标准的传统方法往往缺乏精度。最近，人们开始探索监督机器学习技术，特别是人工神经网络(ANN)。然而，传统的人工神经网络需要大量的数据来进行泛化，这对于钢制螺栓t型短段连接来说是有限的。为了解决这些挑战，本研究探索了使用模型不可知元学习(MAML)来预测钢螺栓t -短节连接的最大循环弯矩阻力的可行性。MAML快速适应特定于任务的模型参数，并跨任务传输知识以微调全局模型参数，从而在有限的数据下潜在地提高预测精度。首先利用贝叶斯优化和高斯过程模型对MAML模型进行优化，以识别理想的超参数。然后将优化后的MAML模型与两种人工神经网络模型(一种具有优化后的超参数，另一种匹配MAML的神经网络结构)和ASCE 41-17方法进行比较。结果表明，优化后的MAML模型具有良好的泛化能力，为钢螺栓t型短段连接提供了一种有前途的方法。来源：复合材料力学仿真Composites FEM

【新文速递】2024年9月12日复合材料SCI期刊最新文章

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【新文速递】2024年7月30日固体力学SCI期刊最新文章