今日更新：International Journal of Solids and Structures 1 篇，Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 8 篇International Journal of Solids and StructuresMulti-step deformation lattice structures from the rotation of unit cellXiaodong Ma, Ning Zhang, Yujia Chang, Xiaogeng Tiandoi:10.1016/j.ijsolstr.2023.112599单元格旋转产生的多级变形晶格结构A multi-step deformation lattice structure (MSLS) is introduced. MSLS can exhibit multiple deformation pathways under compression. It leads to multi-stress plateaus in the stress-strain relationship. The underlying mechanism is caused by the rotation of the unit cell that composes the structures. Analytical models of plateau stress is first established based on the plastic hinge dissipation principle and is validated by experiments. By studying the MSLS composed of different unit cells rotated with different angles, four stress-strain relationships are obtained. Furthermore, the Young's modulus and the yield strength of MSLS show a tendency of decreasing and then increasing with the increase of rotation angle. Moreover, the rotation angle can lead to a transition of the MSLS between bending-dominated behavior and stretching-dominated behavior. Finally, it is found that MSLS has a negative Poisson's ratio and a minimum value is -0.9, and Poisson's ratio tends to zero rapidly when strains is larger than 0.3. This work provides new insights into the use of rotating unit cell to create multi-step pathways and auxetic lattices that can be used to design engineering structures with multiple tasks and application for impact protection.介绍了一种多级变形晶格结构（MSLS）。MSLS 在压缩条件下可表现出多种变形途径。它导致了应力-应变关系中的多应力高原。其基本机制是由组成结构的单元格旋转引起的。首先根据塑性铰链耗散原理建立了高原应力的分析模型，并通过实验进行了验证。通过研究由不同旋转角度的单元格组成的 MSLS，得到了四种应力-应变关系。此外，随着旋转角度的增大，MSLS 的杨氏模量和屈服强度呈现先减小后增大的趋势。此外，旋转角度会导致 MSLS 在弯曲主导行为和拉伸主导行为之间发生转变。最后，研究发现 MSLS 的泊松比为负值，最小值为-0.9，当应变大于 0.3 时，泊松比迅速趋于零。这项研究为利用旋转单元单元创建多级路径和辅助晶格提供了新的见解，这些路径和晶格可用于设计具有多重任务的工程结构，并可应用于冲击防护。Journal of the Mechanics and Physics of SolidsEnhancing the crack initiation resistance of hydrogels through crosswise cuttingZidi Zhou, Yetong Jia, Wenjing Lu, Jincheng Lei, Zishun Liudoi:10.1016/j.jmps.2023.105516通过横向切割增强水凝胶的抗开裂性The achievement of tough adhesion between hydrogels and solid surfaces has significantly expanded the potential applications of hydrogels. This robust adhesion is commonly attained by combining tough hydrogels with strong interfacial bonding and it is reflected in high adhesion toughness. However, the practical use of such strategies is limited since enhanced adhesion diminishes rapidly after cyclic loading. Furthermore, relying solely on adhesion toughness as a measure of adhesion quality may underestimate the adhesive's bearing capacity. To address these issues, here we introduce a macro-structural design strategy called crosswise cutting in hydrogels and propose a new measure of hydrogel adhesion named crack initiation resistance. This strategy can significantly enhance hydrogel adhesion by increasing the peak peel force while constraining the crack initiation length, thus improving the crack initiation resistance. The toughening mechanism behind this strategy is further explored by decomposing the crosswise cutting into longitudinal and transverse cuttings. Through extensive experiments, we demonstrate that longitudinal cutting can increase both the peak peel force and crack initiation length during peeling. Conversely, transverse cutting can constrain the crack initiation length while maintaining a high peak peel force. To quantitatively evaluate the crack initiation resistance of an adhesion system, we define a new parameter, the critical crack initiation energy release rate (Gc*), which considers both the peak peel force and crack initiation length. Theoretical derivations of Gc* for hydrogels with longitudinal and transverse cuttings are provided. By varying cutting types, hydrogel thickness, and cut sizes, the value of Gc* can be significantly increased, with the optimal choice being the crosswise cutting satisfying specific dimensions. The underlying mechanisms pertaining to the increase of Gc* via crosswise cutting are explained by the stress de-concentration effect, and the value of Gc* can be predicted by the modified Lake-Thomas model. It is hoped that this study will draw attention to the assessment of the adhesion quality of hydrogels in practical applications and provide some new insights for the design of future soft adhesives.水凝胶与固体表面之间的强力粘合大大拓展了水凝胶的潜在应用领域。这种强大的粘附力通常是通过将坚韧的水凝胶与强大的界面粘合力相结合而实现的，并反映在高粘附韧性上。然而，这种策略的实际应用受到限制，因为增强的粘附力在循环加载后会迅速减弱。此外，仅仅依靠粘附韧性来衡量粘附质量可能会低估粘合剂的承载能力。为了解决这些问题，我们在此引入了一种名为水凝胶横向切割的宏观结构设计策略，并提出了一种名为抗裂纹起始性的新的水凝胶粘附性测量方法。这种策略可以在限制裂纹起始长度的同时，通过增加峰值剥离力来显著增强水凝胶的粘附性，从而提高抗裂纹起始性。通过将横向切割分解为纵向和横向切割，我们进一步探索了这一策略背后的增韧机制。通过大量实验，我们证明纵向切削可以提高剥离过程中的峰值剥离力和裂纹起始长度。相反，横向切割可以在保持较高峰值剥离力的同时，限制裂纹萌发长度。为了定量评估粘附系统的抗裂纹萌发能力，我们定义了一个新参数--临界裂纹萌发能量释放率（Gc），它同时考虑了峰值剥离力和裂纹萌发长度。我们提供了纵向和横向切割水凝胶的 Gc 理论推导。通过改变切割类型、水凝胶厚度和切割尺寸，可以显著提高 Gc 值，最佳选择是满足特定尺寸的横向切割。应力去集中效应解释了通过横向切割提高 Gc 值的基本机制，而 Gc 值可通过修正的 Lake-Thomas 模型进行预测。希望这项研究能引起人们对实际应用中水凝胶粘附质量评估的关注，并为未来软粘合剂的设计提供一些新的见解。Mechanics of MaterialsAn electroplastic constitutive model of fcc metals and their alloys under high current densityZhifeng Dai, Ke Jin, Yong Koudoi:10.1016/j.mechmat.2023.104878高电流密度下 fcc 金属及其合金的电塑性结构模型The mechanical behavior of fcc (face center cubic) metals and their alloys such as copper-based and aluminum-based materials changes obviously under high current density, but there is a lack of suitable constitutive model to describe the electroplastic behavior of these materials, which limits the accuracy of the mechanical response prediction in applications, such as electromagnetic launch. In this paper, a novel nonlinear constitutive model for electroplastic behavior under the high current density of fcc metals and their alloys is proposed. The model proposed is based on the theory of dislocation evolution, energy transfer theory and electron transport theory and takes into account the effects of high current density on dislocation density, strain rate and resistivity. Considering the evolution of forward and reverse dislocations caused by pulsed current, the relationship between the evolution rate of reverse dislocation and strain is established. Due to the sensitivity of the electroplastic effect to strain rate, the strain rate under electric current is obtained by combining the theory of dislocation thermal activation and energy transfer. According to the concept of thermal resistance and dislocation resistance, the relationship between resistance and current density is derived. The quantitative results demonstrate that this model can well capture the flow stress softening under high current density (>3000 A/mm2) and the transient hardening after current removal because of the consideration of a more suitable strain rate and dislocation evolution. The critical current density that has a significant effect on the strain rate and the current density corresponding to the subsection point of the resistivity are quantitatively obtained. Especially, it is shown that the evolution rate of the reverse dislocation decreases nonlinearly with the increase of strain after the current is removed. These results will be helpful to study the mechanical behavior of the rail during electromagnetic launch and further optimize the design of electromagnetic launch device.fcc（面心立方）金属及其合金，如铜基和铝基材料，在高电流密度下的力学行为会发生明显变化，但目前缺乏合适的构成模型来描述这些材料的电塑性行为，这限制了电磁发射等应用中力学响应预测的准确性。本文针对 fcc 金属及其合金在高电流密度下的电塑行为提出了一种新的非线性构成模型。该模型基于位错演化理论、能量转移理论和电子传输理论，并考虑了高电流密度对位错密度、应变率和电阻率的影响。考虑到脉冲电流引起的正向和反向位错演化，建立了反向位错演化率与应变之间的关系。由于电塑性效应对应变率的敏感性，结合位错热活化和能量传递理论得到了电流下的应变率。根据热阻和位错电阻的概念，推导出电阻与电流密度之间的关系。定量结果表明，由于考虑了更合适的应变率和位错演化，该模型能很好地捕捉高电流密度（>3000 A/mm2）下的流动应力软化和电流消除后的瞬态硬化。定量得出了对应变率有显著影响的临界电流密度以及与电阻率分界点相对应的电流密度。特别是，研究表明，移除电流后，反向位错的演化率随应变的增加而非线性下降。这些结果将有助于研究电磁发射过程中轨道的力学行为，并进一步优化电磁发射装置的设计。International Journal of PlasticityA steady-state irradiation creep and thermal creep model for zirconium alloysShilin Li, Hanlu Xie, Long Yu, Xiazi Xiaodoi:10.1016/j.ijplas.2023.103814锆合金的稳态辐照蠕变和热蠕变模型In this work, a mechanistic steady-state creep model is developed to characterize the macroscopic strain rate of metallic materials affected by irradiation flux, testing temperature and applied stress. Thereinto, the steady-state strain rate is obtained by considering the density evolution of mobile dislocations, which involve the mechanisms of dislocation multiplication, dynamic annihilation and time-dependent dislocation annihilation. In order to effectively analyze the irradiation creep behavior in the low and high stress region, main attentions are focused on the influence of dislocation mobility on the process of time-dependent dislocation annihilation. At low stress, dislocation mobility is affected by dislocation climb and thermally activated glide. For the former, the absorption of irradiation-induced point defects can promote dislocation climb; whereas, thermally activated dislocation glide might be inhibited by the existing defect clusters. At high stress, the dominant deformation mechanism changes from dislocation climb to displacement cascade unpinning. For the latter, an explicit formula for dislocation mobility is deduced to address the influence of dislocation unpinning from the barriers on irradiation creep. To further verify the established model, thermal creep and irradiation creep data of zirconium alloys are considered to compare with the theoretical results. A good agreement is achieved over a wide range of temperature and stress indicating that the model can well describe the deformation behavior of steady-state creep. In addition, contribution of the dominant dislocation mobility components and dislocation density evolution components is compared under both thermal and irradiation creep, which can facilitate the comprehension of fundamental creep mechanisms of metallic materials.本研究建立了一个力学稳态蠕变模型，以描述金属材料受辐照通量、测试温度和外加应力影响的宏观应变速率。其中，稳态应变速率是通过考虑移动位错的密度演化得到的，涉及位错倍增、动态湮灭和随时间变化的位错湮灭机制。为了有效分析低应力和高应力区的辐照蠕变行为，主要关注了位错迁移率对随时间变化的位错湮灭过程的影响。在低应力下，位错迁移率受位错爬升和热激活滑行的影响。对于前者，辐照诱导的点缺陷的吸收可促进位错攀升；而热激活的位错滑行则可能受到现有缺陷簇的抑制。在高应力下，主要的变形机制从位错攀升转变为位错级联解宁。针对后者，我们推导出了一个明确的位错迁移率公式，以解决位错从势垒解脱对辐照蠕变的影响。为了进一步验证所建立的模型，研究人员考虑了锆合金的热蠕变和辐照蠕变数据，并将其与理论结果进行比较。在很宽的温度和应力范围内，二者的一致性都很好，这表明该模型能很好地描述稳态蠕变的变形行为。此外，还比较了热蠕变和辐照蠕变下主要位错移动成分和位错密度演化成分的贡献，这有助于理解金属材料的基本蠕变机制。Thin-Walled StructuresStudy on physical explosion equivalent of large diameter and high pressure natural gas pipelineHuayuan Ma, Xinghua Li, Xingbo Xie, Yaru Lv, Miao Yao, Mingshou Zhong, Junnan Zhangdoi:10.1016/j.tws.2023.111419大口径高压天然气管道物理爆炸当量研究High pressure natural gas pipelines are prone to material failure and explosion due to various reasons. Over the years, scholars have done in-depth research on the process of chemical explosion. In this paper, the energy components of high-pressure trunk natural gas pipeline under normal operation state were derived. Based on the assumption of adiabatic non isentropic, the pressure distribution in the pipeline within a period of time after the pipeline cracks was derived, and the energy released by the physical explosion of the pipeline was further derived. To verify the theoretical results, an original size pipe explosion experiment was organized, and the pressure distribution obtained from the experiment was found to be in good agreement with the theoretical calculation results. Through the crack propagation time and the duration of ground motion obtained from the experiment, the range of the duration of the pipeline burst crack impact was obtained, and the equivalent range of the pipeline explosion was further calculated. At the same time, through the regression analysis of ground motion, the equivalent of the pipe explosion in this experiment was about 160kg TNT, which was consistent with the theoretical results. Further, the theoretical model and experimental results were verified by numerical simulation, and deeply studied the influence factors of buried depth on the explosion equivalent, as well as the relationship between the environment of the pipeline and the explosion damage mode and hazard range of the pipeline. The research results of this paper give the calculation method and magnitude range of physical explosion equivalent of high-pressure trunk natural gas pipeline. It provides a reference for the formulation of safety standards for high-pressure trunk natural gas pipelines and inert gas pressure vessels.由于各种原因，高压天然气管道容易发生材料故障和爆炸。多年来，学者们对化学爆炸过程进行了深入研究。本文推导了高压天然气干线管道在正常运行状态下的能量分量。在绝热非等熵假设的基础上，推导了管道裂缝后一段时间内管道内的压力分布，并进一步推导了管道物理爆炸释放的能量。为了验证理论结果，组织了一次原始尺寸的管道爆炸实验，实验得出的压力分布与理论计算结果非常吻合。通过实验得到的裂纹传播时间和地面运动持续时间，得到了管道爆裂裂纹冲击持续时间的范围，并进一步计算了管道爆炸的等效范围。同时，通过对地面运动的回归分析，本次实验中管道爆炸的当量约为 160kg TNT，与理论结果一致。此外，还通过数值模拟验证了理论模型和实验结果，并深入研究了埋深对爆炸当量的影响因素，以及管道所处环境与管道爆炸破坏模式和危害范围之间的关系。本文的研究成果给出了高压干线天然气管道物理爆炸当量的计算方法和量级范围。为高压干线天然气管道和惰性气体压力容器安全标准的制定提供了参考。Seismic damage assessment for flexural double skin composite walls based on the modified Park-Ang modelHaowen Hou, Wei Wang, Yuelin Zhangdoi:10.1016/j.tws.2023.111445基于修正的 Park-Ang 模型的挠性双层复合墙体地震破坏评估The damage indices are widely used to evaluate the performance level and damage state of structural elements in buildings subjected to seismic actions. Despite the widespread promotion of double-skin composite walls (DSCWs) in global construction practices, the research related to the seismic damage assessment of DSCW members is still limited. In order to establish a seismic damage assessment procedure for DSCW members, an experimental database that includes 37 test results of DSCW specimens subjected to cyclic loads was built in this paper. Based on an existing modified Park-Ang model, an empirical expression of the combination coefficient is introduced. Six damage state levels of DSCWs are determined as follows: Basically intact (DS0), Slight damage (DS1), Mild damage (DS2), Moderate damage (DS3), Relatively severe damage (DS4), Severe damage (DS5), and Critical collapse (DS6). The typical damage characteristics and repair methods are introduced and discussed. Subsequently, a comprehensive statistical analysis is conducted to study the probabilistic correlation between these damage states and the corresponding index specific to DSCW members. Fragility functions for each damage state associated with the damage index have been developed. The threshold values of the damage index corresponding to the damage states are also provided. This paper intends to provide a theoretical foundation for performance-based seismic design and post-earthquake damage assessment of DSCW structures.破坏指数被广泛用于评估建筑物在地震作用下的性能水平和结构构件的破坏状态。尽管双层复合墙体（DSCW）在全球建筑实践中得到广泛推广，但与双层复合墙体构件地震损伤评估相关的研究仍然有限。为了建立 DSCW 构件的地震破坏评估程序，本文建立了一个实验数据库，其中包括 37 个 DSCW 试件在循环荷载作用下的测试结果。基于现有的修正 Park-Ang 模型，引入了组合系数的经验表达式。DSCW 的六种损伤状态等级确定如下：基本完好（DS0）、轻微损坏（DS1）、轻度损坏（DS2）、中度损坏（DS3）、相对严重损坏（DS4）、严重损坏（DS5）和临界坍塌（DS6）。介绍并讨论了典型的损坏特征和修复方法。随后，进行了全面的统计分析，以研究这些损坏状态与 DSCW 构件特有的相应指数之间的概率相关性。开发了与损伤指数相关的每种损伤状态的脆性函数。此外，还提供了与损伤状态相对应的损伤指数阈值。本文旨在为基于性能的 DSCW 结构抗震设计和震后损伤评估提供理论基础。Experimental and numerical study on the impact performance of concrete-filled high-strength steel tube (CFHSST)Chuan-Chuan Hou, Da-Hao Wu, Dan-Yang Madoi:10.1016/j.tws.2023.111450混凝土填充高强度钢管（CFHSST）冲击性能的实验和数值研究The performance of concrete-filled high-strength steel tubes (CFHSST) under transverse impact was studied through experiments and numerical analysis in this paper. A total of 14 specimens of concrete-filled BG890QL high-strength steel tubes and 8 specimens of concrete-filled Q345B carbon steel tubes were tested using a drop hammer apparatus. Test results showed that CFHSST presents a bending failure under transverse impact and has good impact resistance. However, CFHSST with a higher axial compression or bending resistances show lower impact resistance compared to that of the concrete-filled carbon steel tubes (CFST). This may be due to the relatively lower strain rate effect and the characters of the constitutive relation of the high-strength steel. A finite element analysis (FEA) model was then established to broadly compare the impact resistance of CFHSST and CFST. The finite element analysis shows that the impact resistance of CFHSST members is higher than that of CFST members with the same axial compression resistance and static bending resistance when the impact energy is relatively low. However, with the increase of the impact energy, the impact resistance of CFHSST is gradually lower than that of CFST, showing its potential mechanical shortcomings under extreme hazards compared to the conventional CFST. Finally, based on a parametric analysis, key parameters that may influence the impact resistance of CFHSST are identified.本文通过实验和数值分析研究了混凝土填充高强度钢管（CFHSST）在横向冲击下的性能。使用落锤仪测试了 14 个混凝土填充 BG890QL 高强度钢管试件和 8 个混凝土填充 Q345B 碳素钢管试件。测试结果表明，CFHSST 在横向冲击下会出现弯曲破坏，具有良好的抗冲击性。然而，与填充混凝土的碳钢管（CFST）相比，轴向抗压或抗弯强度较高的 CFHSST 的抗冲击性能较低。这可能是由于相对较低的应变率效应和高强度钢的构成关系特性造成的。随后建立了有限元分析模型，对 CFHSST 和 CFST 的抗冲击性能进行了大致比较。有限元分析表明，当冲击能量相对较低时，在轴向抗压性和静态抗弯性相同的情况下，CFHSST 构件的抗冲击性要高于 CFST 构件。然而，随着冲击能量的增加，CFHSST 的抗冲击性能逐渐低于 CFST，这表明与传统 CFST 相比，CFHSST 在极端危险情况下可能存在力学缺陷。最后，基于参数分析，确定了可能影响 CFHSST 抗冲击性能的关键参数。Experimental investigation on the dynamic response of half steel-concrete composite slabs under low-velocity impactZhe Zhang, Quanquan Guo, Xuqiang Dou, Yapeng Liudoi:10.1016/j.tws.2023.111451半钢-混凝土复合板在低速冲击下的动态响应实验研究The current research on the dynamic response of half steel-concrete (HSC) composite slabs is not only limited but also primarily concentrated on high-velocity impacts. This study investigates the dynamic response of such structures by examining failure modes, impact resistance mechanisms, and energy dissipation under low-velocity impacts through drop hammer impact tests conducted on five HSC specimens. In addition, the variation of the out-of-plane residual bearing capacity with the damage degree of specimens and impact energy is analyzed using static loading tests. Finally, the dynamic response differences between half steel-concrete slabs and steel-concrete (SC) slabs are analyzed by comparing multiple indicators. The results indicate that HSC slabs exhibit five distinct failure modes when subjected to low-velocity impact within a range of 3.13 m/s to 7.00 m/s. Additionally, five stages of the dynamic response process of the HSC slabs are proposed. Moreover, the bottom steel plate plays a crucial role in retaining structural out-of-plane residual bearing capacity. Furthermore, compared with the SC structure, the HSC slab is capable of absorbing input impact energy within a much smaller displacement.目前对半钢-混凝土（HSC）复合楼板动态响应的研究不仅有限，而且主要集中在高速冲击方面。本研究通过对五个 HSC 试样进行落锤冲击试验，研究低速冲击下的破坏模式、抗冲击机制和能量耗散，从而探讨此类结构的动态响应。此外，还利用静态加载试验分析了平面外残余承载力随试样损坏程度和冲击能量的变化。最后，通过比较多个指标，分析了半钢-混凝土板和钢-混凝土（SC）板的动态响应差异。结果表明，当受到 3.13 米/秒至 7.00 米/秒范围内的低速冲击时，HSC 板表现出五种不同的破坏模式。此外，还提出了 HSC 板动态响应过程的五个阶段。此外，底部钢板在保持结构平面外剩余承载力方面起着至关重要的作用。此外，与 SC 结构相比，HSC 板能够在更小的位移范围内吸收输入的冲击能量。Experimental and numerical studies of the multi-tube assembled buckling-restrained bracesMengsi Wei, Kejian Ma, Bo Yuan, Shiyu Zheng, Jing Chendoi:10.1016/j.tws.2023.111453多管装配式屈曲约束支撑的实验和数值研究In this paper, the multi-tube assembled bolt-connected buckling-restrained brace (MT-BRB) with four internally restrained rectangular steel tubes and one externally restrained square steel tube is experimentally analyzed. This study conducted cyclic loading tests on five specimens with different parameters to investigate the effects of different loading directions of the core plate, the presence or absence of unbonded materials, the gap-to-width ratio and the width-to-thickness ratio on the mechanical properties, seismic performance and failure mode of MT-BRB. The experimental results indicated that the MT-BRB specimens made of unbonded materials had stable cyclic performance and energy dissipation capacity. Subsequently, the same numerical model as the experimental specimen was established, and the hysteresis and stress curves extracted from the finite element model were compared with the experimental results. The simulation had ideal agreement with the experiment result, demonstrating that the model was effective for performance predictions. Based on this, the working mechanism of MT-BRB was further explored through finite element analysis. Finally, parameter analysis was conducted on the constraint ratio and constraint length ratio to further investigate the energy dissipation performance of MT-BRB. This study is beneficial for promoting the application of MT-BRB in energy dissipation and vibration reduction engineering.本文对具有四根内部约束矩形钢管和一根外部约束方形钢管的多管装配式螺栓连接屈曲约束支撑（MT-BRB）进行了实验分析。该研究对五个不同参数的试件进行了循环加载试验，以研究不同加载方向的芯板、有无未粘结材料、间隙与宽度之比以及宽度与厚度之比对 MT-BRB 的力学性能、抗震性能和破坏模式的影响。实验结果表明，无粘结材料制成的 MT-BRB 试件具有稳定的循环性能和耗能能力。随后，建立了与实验试件相同的数值模型，并将从有限元模型中提取的滞后和应力曲线与实验结果进行了比较。模拟结果与实验结果非常吻合，表明该模型在性能预测方面非常有效。在此基础上，通过有限元分析进一步探讨了 MT-BRB 的工作机理。最后，对约束比和约束长度比进行了参数分析，进一步研究了 MT-BRB 的耗能性能。这项研究有利于促进 MT-BRB 在消能减震工程中的应用。AT-PINN: Advanced time-marching physics-informed neural network for structural vibration analysisZhaolin Chen, Siu-Kai Lai, Zhichun Yangdoi:10.1016/j.tws.2023.111423AT-PINN：用于结构振动分析的高级时间行进物理信息神经网络Solving partial differential equations through deep learning has recently received wide attention, with physics-informed neural networks (PINNs) being successfully used and showing great potential. This study focuses on the development of an efficient PINN approach for structural vibration analysis in “long-duration” simulation that is still a technical but unresolved issue of PINN. The accuracies of the standard PINN (STD-PINN) and conventional time-marching PINN (CT-PINN) methods in solving vibration equations, especially free-vibration equations, are shown to decrease to varying degrees with the simulation time. To resolve this problem, an advanced time-marching PINN (AT-PINN) approach is proposed. This method is used to solve structural vibration problems over successive time segments by adopting four key techniques: normalization of the spatiotemporal domain in each time segment, a reactivating optimization algorithm, transfer learning and the sine activation function. To illustrate the advantages of the AT-PINN approach, numerical simulations of the forced and free vibration of a string, beam and plate are performed. In addition, the vibration analysis of a plate under multi-physics loads is also studied. The results show that the AT-PINN approach can provide accurate solutions with lower computational cost even in long-duration simulation. The techniques adopted are verified to effectively avoid the offset of the spatiotemporal domain, reduce the accumulative error and enhance the training efficiency. The present one overcomes the drawback of the existing PINN methods and is expected to become an effective method for solving time-dependent partial differential equations in long-duration simulation.通过深度学习求解偏微分方程近来受到广泛关注，其中物理信息神经网络（PINN）得到了成功应用，并显示出巨大潜力。本研究的重点是开发一种高效的 PINN 方法，用于 "长时间 "仿真中的结构振动分析。研究表明，标准 PINN（STD-PINN）和传统的时间行进 PINN（CT-PINN）方法在求解振动方程，尤其是自由振动方程时，其精度会随着模拟时间的延长而出现不同程度的下降。为了解决这个问题，我们提出了一种先进的时间行进 PINN（AT-PINN）方法。该方法通过采用以下四种关键技术来解决连续时间段的结构振动问题：每个时间段时空域的归一化、重新激活优化算法、迁移学习和正弦激活函数。为了说明 AT-PINN 方法的优势，我们对弦、梁和板的受力振动和自由振动进行了数值模拟。此外，还研究了板在多物理载荷下的振动分析。结果表明，即使在长时间模拟中，AT-PINN 方法也能以较低的计算成本提供精确的解决方案。经过验证，所采用的技术能有效避免时空域偏移、减少累积误差并提高训练效率。本方法克服了现有 PINN 方法的缺点，有望成为在长时间仿真中求解时变偏微分方程的有效方法。A concurrent design optimization framework for IMSFRP composite structures considering material and structural parameters simultaneouslyHanyu Zhang, Zhouzhou Song, Yacong Zhang, Lei Zhang, Ping Zhudoi:10.1016/j.tws.2023.111449同时考虑材料和结构参数的 IMSFRP 复合结构并行优化设计框架Injection molded short fiber reinforced polymer (IMSFRP) composite is a widely used lightweight material in the automobile industry. Due to the integrated molding characteristics of IMSFRP composite structures, its lightweight potential can be fully exploited through the simultaneous design of material and structural parameters. However, the efficient material-structure parallel optimization design method for IMSFRP composite structures has not been fully investigated. In this study, a framework of lightweight design containing the concurrent optimization of material and structure parameters is proposed, and it has been successfully applied to an automobile IMSFRP composite liftgate inner. Firstly, considering the skin-core-skin (SCS) structure of the material, a layered model is built up and a parameterized constitutive model is established to efficiently obtain material properties for various material parameters. Then, a parameter extraction and mapping method is proposed to map fiber distribution information to the structural analysis model to improve the accuracy of structural analysis. In addition, based on the Kriging model and a newly developed parallel boundary search particle swarm optimization algorithm, a lightweight design framework of composite liftgate inner is proposed to consider the material and structural design variables simultaneously. The results show that the proposed framework can solve the concurrent optimization design problem effectively and achieve a weight reduction of 10.5% for the composite liftgate inner under multiple working conditions.注塑短纤维增强聚合物（IMSFRP）复合材料是汽车行业广泛使用的一种轻质材料。由于 IMSFRP 复合材料结构具有一体化成型的特点，因此可以通过材料和结构参数的同步设计充分挖掘其轻量化潜力。然而，针对 IMSFRP 复合材料结构的高效材料-结构并行优化设计方法尚未得到充分研究。本研究提出了包含材料和结构参数并行优化的轻量化设计框架，并成功应用于汽车 IMSFRP 复合材料举升门内部。首先，考虑到材料的皮-芯-皮（SCS）结构，建立了分层模型和参数化构成模型，从而有效地获得各种材料参数的材料特性。然后，提出了一种参数提取和映射方法，将纤维分布信息映射到结构分析模型中，以提高结构分析的精度。此外，基于克里金模型和新开发的并行边界搜索粒子群优化算法，提出了同时考虑材料和结构设计变量的复合材料升降门内部轻量化设计框架。结果表明，所提出的框架能有效解决并行优化设计问题，并在多种工况下实现复合材料升降门内胆减重 10.5%。Cyclic behavior of dual-steel beam-to-column welded flange-bolted web connectionsFangxin Hu, Zhan Wangdoi:10.1016/j.tws.2023.111452双钢梁对柱焊接法兰-螺栓腹板连接的循环行为Cyclic loading tests on dual-steel beam-to-column welded flange-bolted web connections were conducted to quantify their moment resistance, plastic deformation and energy dissipation capacities. The test program consisted of five one-sided connection specimens, where Q355 grade beams and Q690 grade columns were used, to study the effects of beam-to-column welded flange connection details and panel zone shear strength on the connection seismic performance. Two types of welded connection details were considered; one was the traditional complete-joint-penetration (CJP) welded connections by use of backing bars, and the other type was those with the bottom backing bar further reinforced by a fillet weld. Three column web thicknesses were designed to arrive at strong, intermediate and weak panel zones, respectively. It was found that the CJP weld with the backing bar reinforced only under the bottom beam flange produced satisfactory performance and accommodated plastic rotations larger than 0.03 rad, while a maximum plastic rotation of 0.04 rad could be developed in the high-strength steel panel zone before fracture occurred. These results evidenced that those dual-steel connections could still sustain high seismic deformation demands.对双钢梁-柱焊接翼缘-螺栓腹板连接进行了循环加载试验，以量化其抗弯矩、塑性变形和耗能能力。试验项目包括五个单侧连接试件，使用 Q355 等级的梁和 Q690 等级的柱，研究梁柱焊接翼缘连接细节和面板区剪切强度对连接抗震性能的影响。研究考虑了两种类型的焊接连接细节：一种是使用支撑杆的传统全连接贯穿（CJP）焊接连接，另一种是底部支撑杆通过角焊缝进一步加固的连接。设计了三种柱腹板厚度，分别用于强板区、中间板区和弱板区。结果发现，仅在梁底翼缘板下加固支撑杆的 CJP 焊缝性能令人满意，可承受大于 0.03 rad 的塑性旋转，而在高强度钢板区，在发生断裂之前，最大塑性旋转可达 0.04 rad。这些结果表明，这些双钢连接仍能承受较高的地震变形要求。来源：复合材料力学仿真Composites FEM
