今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 2 篇,International Journal of Plasticity 3 篇,Thin-Walled Structures 9 篇
Optimization of slenderness ratio and visco-elastic material properties in a 2D hybrid auxetic lattice for enhanced impact mitigation
Xuedong Zhai, Xiaoming Mao, Ellen M. Arruda
doi:10.1016/j.ijsolstr.2025.113659
优化二维杂化形变晶格的长细比和粘弹性材料性能,以增强抗冲击能力
Armor is known to protect underlying targets by reducing force trans mission during impact events. However, the kinetic energy associated with an impact, often underappreciated, can be as destructive as the force, causing relative motion in the target and consequent damage. Therefore, efficient protective gear and packaging should be lightweight and effective at both force reduction and energy mitigation. Although auxetic lattices have been studied as lightweight alternatives for force reduction, the simultaneous optimization of force reduction and energy dissipation in impact mitigation, through geometric configurations and material selection, has not been addressed. In the present study, we demonstrate that a 2D auxetic lattice, optimized for the slenderness ratio of its struts and for elastic and viscoelastic material properties, can not only reduce the trans mitted peak force but also significantly mitigate energy. By employing a multi-step optimization method integrated with Finite Element (FE) ana lysis, we achieve an optimal auxetic lattice design that simultaneously considers both peak force and energy mitigation. Our results are further validated through theoretical an alyses from existing literature.
众所周知,在撞击事件中,装甲通过减少力的传递来保护潜在的目标。然而,与撞击相关的动能,经常被低估,可能与力一样具有破坏性,导致目标的相对运动和随之而来的破坏。因此,有效的防护装备和包装应该是轻量级的,在减少力量和减少能量方面都是有效的。虽然已经研究了作为减力的轻量级替代方案的减力晶格,但通过几何配置和材料选择同时优化减力和能量耗散的冲击缓解,尚未得到解决。在本研究中,我们证明了一种针对其支撑的长细比以及弹性和粘弹性材料性能进行优化的二维auxetic晶格,不仅可以减少传递的峰值力,还可以显着减轻能量。通过采用与有限元分析相结合的多步优化方法,我们实现了同时考虑峰值力和能量缓解的最佳辅助晶格设计。通过对已有文献的理论分析,进一步验证了我们的研究结果。
A fully coupled THMC-MPM framework for modeling coupled phase transition and large deformation in methane hydrate-bearing sediment
Jidu Yu, Jidong Zhao, Kenichi Soga, Shiwei Zhao, Weijian Liang
doi:10.1016/j.jmps.2025.106368
基于全耦合THMC-MPM框架的含甲烷水合物沉积物相变与大变形模拟
Methane hydrate-bearing sediment (MHBS) is a multiphase granular system characterized by complex thermo-hydro-mechanical–chemical (THMC) interactions involving phase transitions and large deformation behavior. Hydrate dissociation weakens sediment strength, potentially initiating geohazards such as submarine landslides. Simultaneously, large deformations in MHBS alter the sediment’s state, influencing hydrate reaction kinetics. Despite recent progress, modeling the coupled processes of hydrate dissociation and large deformation in MHBS remains a significant challenge. This study develops a THMC-coupled material point method (MPM) framework to simulate the pre- to post-failure behavior of MHBS associated with hydrate dissociation. The framework incorporates three key advancements: (i) a six-field governing equation integrated with the Kim-Bishnoi hydrate reaction model to resolve dynamic phase transitions, multiphase interactions, and large deformations; (ii) a strain-softening Mohr–Coulomb model with hydrate saturation-dependent strength to capture sediment mechanical degradation; and (iii) a hybrid explicit-implicit time integration scheme designed to enhance computational efficiency for systems with low permeability and high reaction rates. The framework is validated against Masuda’s hydrate dissociation experiment and an extended Terzaghi consolidation benchmark, before being applied to simulate biaxial compression tests and hydrate dissociation-triggered slope failures. We reveal that (1) shear dilation generates negative excess pore pressure in undrained conditions, triggering hydrate dissociation within the shear bands ; (2) shear heating resulting from rapid, large deformation promotes hydrate dissociation, exacerbating sediment softening; and (3) sediment strength degradation, hydrothermal variations, slope geometry, and other factors collectively shape the dynamic progression of retrogressive failures in MHBS. This work provides a powerful framework for modeling hydrate-related granular mechanics and geohazards.
甲烷水合物沉积物(MHBS)是一种多相颗粒体系,具有复杂的热-水-机械-化学(THMC)相互作用,涉及相变和大变形行为。水合物分解会削弱沉积物的强度,可能引发海底滑坡等地质灾害。同时,MHBS的大变形改变了沉积物的状态,影响了水合物反应动力学。尽管最近取得了进展,但在MHBS中模拟水合物解离和大变形的耦合过程仍然是一个重大挑战。本研究开发了一个thmc耦合的物质点法(MPM)框架来模拟MHBS与水合物解离相关的失效前到失效后的行为。该框架包含三个关键进展:(i)集成了Kim-Bishnoi水合物反应模型的六场控制方程,以解决动态相变、多相相互作用和大变形;(ii)基于水合物饱和度相关强度的应变软化Mohr-Coulomb模型来捕捉沉积物的力学退化;(iii)一种混合显式-隐式时间积分方案,旨在提高低渗透率和高反应速率系统的计算效率。该框架通过Masuda的水合物解离实验和扩展的Terzaghi固结基准进行验证,然后应用于模拟双轴压缩试验和水合物解离引发的边坡破坏。研究发现:(1)在不排水条件下,剪切膨胀产生负超孔隙压力,引发剪切带内水合物解离;(2)快速大变形引起的剪切加热促进水合物解离,加剧沉积物软化;(3)沉积物强度退化、热液变化、边坡几何形状等因素共同影响了MHBS中退化破坏的动态进展。这项工作为水合物相关的颗粒力学和地质灾害建模提供了一个强大的框架。
Computational optimization of director patterns in liquid crystal elastomers
Tingting Xu, Thao D. Nguyen, James K. Guest
doi:10.1016/j.jmps.2025.106369
液晶弹性体中定向图案的计算优化
We present a computational framework for optimizing the director distributions in viscoelastic liquid crystal elastomer (LCE) structures. The framework begins with a finite element implementation of a viscoelastic finite strain model to capture the time-dependent behavior of LCEs. This model is coupled with an optimization scheme that optimizes the spatially continuous director field for targeted mechanical performance. A time-dependent adjoint sensitivity an alysis is employed to enable efficient gradient-based design updates. The framework is demonstrated through numerical examples that maximize mechanical work and maximize energy dissipation. Maximizing the mechanical work produces optimized director patterns that are aligned with principal stress directions, resulting in minimal reorientation and increased stiffness. Maximizing the energy dissipation produces director patterns that depend on whether viscous director rotation or network deformation is the dominant dissipation mechanis m. These results highlight opportunities for optimizing LCE structures and underscore the importance of accurately modeling the viscoelastic response when designing LCE structures for reliable, long-term functionality.
提出了一种优化粘弹性液晶弹性体(LCE)结构中定向器分布的计算框架。该框架从粘弹性有限应变模型的有限元实现开始,以捕获LCEs的时间依赖性行为。该模型与优化方案相结合,优化空间连续导向场以实现目标机械性能。采用时间相关的伴随灵敏度分析来实现基于梯度的有效设计更新。通过数值算例证明了该框架能最大限度地实现机械功和能量耗散。最大限度地增加机械功可以优化导向模式,使其与主应力方向一致,从而减少定向,增加刚度。最大限度地耗散能量产生的导向模式取决于粘性导向旋转还是网络变形是主要的耗散机制。这些结果突出了优化LCE结构的机会,并强调了在设计LCE结构时准确建模粘弹性响应的重要性,以获得可靠的长期功能。
Functional fatigue and restoration in superelastic NiTi shape-memory alloys
Junyu Chen, Wenqiang Wang, Fei Liu, Boxin Wei, Liping Lei, Gang Fang, Robert O. Ritchie, Upadrasta Ramamurty
doi:10.1016/j.ijplas.2025.104483
超弹性NiTi形状记忆合金的功能疲劳与恢复
Functional fatigue in NiTi-based shape-memory alloys (S MAs), a critical barrier to their widespread adoption for a variety of technologies, remains a key challenge with incomplete mechanistic understanding. Here we investigate functional fatigue and its restoration in superelastic NiTi S MAs with wide-ranging grain sizes and subjected to elastocaloric cycling under varying maximum applied stresses (σ_max). Results show that larger grain sizes and/or higher σ_max significantly exacerbate the kinematic irreversibility caused by the fatigue-induced increased dislocation density and martensite retention. It is demonstrated that functional restoration can be achieved through a simple overheating treatment (‘healing’) after cycling, which reverts the retained martensite into austenite for subsequent transformation while preserving dislocations. Retained martensite alone lowers the critical forward transformation stress during cycling, but its effect is fully reversible by healing, irrespective of grain size and σ_max. Both dislocations and retained martensite impair the cyclic transformation capacity of the material, leading to elastocaloric degradation. The contribution of retained martensite, which can be revoked by healing for elastocaloric restoration, increases with σ_max and eventually outweighs the influence of dislocations; refinement in the grain size accelerates this transition. The work provides quantitative insights into the micro-mechanis ms underlying functional fatigue and restoration in NiTi S MAs, advancing the development of sustainable elastocaloric technologies.
镍钛基形状记忆合金(S MAs)的功能疲劳是其在多种技术中广泛应用的关键障碍,目前对其机制的理解仍不完整。在此,我们研究了具有不同晶粒尺寸的超弹性镍钛形状记忆合金在不同最大施加应力(σ_max)下的弹性热循环中的功能疲劳及其恢复情况。结果表明,较大的晶粒尺寸和/或较高的σ_max会显著加剧疲劳引起的位错密度增加和马氏体保留所导致的运动不可逆性。我们证明,通过在循环后进行简单的过热处理(“修复”),可以实现功能恢复,这会使保留的马氏体在后续的转变中重新转变为奥氏体,同时保留位错。仅保留的马氏体就会降低循环过程中的临界正向转变应力,但无论晶粒尺寸和σ_max如何,其影响都可以通过修复完全逆转。位错和保留的马氏体都会损害材料的循环转变能力,从而导致弹性热性能下降。残余马氏体的贡献会随着 σ_max 的增大而增加,最终超过位错的影响,其可通过愈合实现弹性热效应的恢复;晶粒尺寸的细化会加速这一转变。该研究为镍钛形状记忆合金的功能疲劳和恢复的微观机制提供了定量见解,推动了可持续弹性热技术的发展。
Prolonged work hardening in bimodal grain structured aluminum matrix composites: a sequential heterostructure effect
Zhiqi Guo, Xiaotong Li, Sijie Wang, Zhanqiu Tan, Zhenming Yue, Bo Cui, Genlian Fan, Zhiqiang Li, Di Zhang
doi:10.1016/j.ijplas.2025.104485
双峰晶粒组织铝基复合材料的长时间加工硬化:顺序异质组织效应
High-strength aluminum matrix composites (AMCs) suffer from poor ductility, due to the limited work hardening capacity. In this study, a remarkable prolonged work hardening is sustained in ultrastrong Al-5Mg matrix composites via an optimized bimodal grain heterostructure, with triple or even fourfold uniform elongation and raised tensile/yield strength. The prolonged work hardening proceeds through two sequential deformation stages. In the first stage with minor strains (<2.5%), a high gradient of geometrically necessary dislocations in soft coarse-grained (CG) zones generates strong back stress, which promotes not only hetero-deformation induced (HDI) hardening but also dislocation multiplication in hard ultrafine-grained (UFG) zones. The work hardening of UFG is thus improved with higher density of dislocations interacting with some nanoparticles. Subsequently, the stress of UFG zones rises sufficiently to induce dispersed microvoids formation within UFG zones, instead of localized cracking at hetero-zone boundaries. Therefore, an effective HDI hardening depending on the well-bonded hetero zones is sustained in the second stage (strain >2.5%). Such a sequential heterostructure effect is an alyzed to obtain an appropriate width range of soft zones for bimodal grained AMCs, improving the conventional empirical heterostructure design principle. This work advances the understandings on heterostructured AMCs that when employing intermediate-sized soft zones, the hard UFG zones play a key role in obtaining good ductility, instead of only providing high strength.
高强度铝基复合材料由于加工硬化能力有限,塑性较差。在本研究中,通过优化的双峰晶粒异质结构,超强Al-5Mg基复合材料持续了显著的长时间加工硬化,具有三倍甚至四倍的均匀伸长率和提高的抗拉/屈服强度。长时间的加工硬化通过两个连续的变形阶段进行。在第一阶段,当应变较小(<2.5%)时,软粗晶区(CG)中几何必需位错的高梯度产生了强背应力,这不仅促进了异质变形诱导(HDI)硬化,而且促进了硬超细晶区(UFG)中的位错增殖。因此,与纳米颗粒相互作用的位错密度越高,UFG的加工硬化就越好。随后,UFG区域的应力上升到足以在UFG区域内形成分散的微孔,而不是在异质区边界处局部开裂。因此,在第二阶段(应变>2.5%),有效的HDI硬化取决于结合良好的异质区。分析了这种顺序异质结构效应,得到了双峰晶型碳纤维的合适软区宽度范围,改进了传统的经验异质结构设计原则。本工作进一步加深了对异质结构碳纤维的理解,即当采用中等大小的软区时,硬区的UFG区在获得良好延性方面起着关键作用,而不仅仅是提供高强度。
A Novel Constitutive Model Emphasizing Disclination-induced Back Stress in Strain Hardening
Jinzhao Li, Zhiping Guan, Junfu Chen, Yongsen Yu
doi:10.1016/j.ijplas.2025.104486
一种强调应变硬化中斜向反应力的新本构模型
Back stress hardening is a component of strain hardening during plastic deformation. Traditionally, the theory of dislocations has attributed the microscopic origin of back stress in polycrystalline metal materials to the long-range stress fields generated by geometrically necessary dislocations (GNDs), which accommodate the translational lattice incompatibility of the crystal. However, the lattice incompatibility also contains a rotational component, associated with disclinations. Similar to GNDs, disclinations also generate long-range internal stress fields, yet their role in back stress remains insufficiently understood. This study introduces a disclination-induced back stress mechanis m and proposes a novel single-ended disclination pile-up model, ana logous to the single-ended GND pile-up model. This model accounts for the reduction in the average distance of long-range stress fields due to the growth of disclinations within grains. Integrating back stress contributions from both GNDs and disclinations, a new constitutive model is developed. Uniaxial tension simulations of 6061-T5 aluminum alloy sheets demonstrate that the predicted back stress from this model closely aligns with experimental results from tension-compression tests, thereby validating its accuracy. The simulation results show that while GND-induced back stress rapidly increases initially and then stabilizes, disclination-induced back stress continues to rise, constituting 65% of the total back stress at a strain of 0.16. This work not only advances our understanding of the origins of back stress in disclinations but also underscores the significance of incorporating disclinations in back stress calculations, offering new insights into the relationship between microstructure evolution and strain hardening behavior.
背应力硬化是塑性变形过程中应变硬化的一个组成部分。传统的位错理论将多晶金属材料中背应力的微观来源归因于几何必要位错(GNDs)产生的远程应力场,这种应力场适应了晶体的平动晶格不相容。然而,晶格不相容也包含一个旋转分量,与偏斜有关。与GNDs类似,斜向也会产生长期的内部应力场,但它们在背应力中的作用仍未得到充分的了解。本研究引入斜交引起的背应力机制,并提出了一种新的单端斜交堆积模型,类似于单端GND堆积模型。该模型解释了由于晶粒内偏斜的生长而导致的远程应力场平均距离的减小。综合GNDs和disations的背应力贡献,建立了一个新的本构模型。对6061-T5铝合金板进行了单轴拉伸仿真,结果表明,该模型预测的背应力与拉伸压缩试验结果吻合较好,验证了该模型的准确性。模拟结果表明,gnd诱导的背应力先快速增大后趋于稳定,而斜斜诱导的背应力持续上升,在应变为0.16时占总背应力的65%。这项工作不仅促进了我们对斜向中背应力起源的理解,而且强调了将斜向纳入背应力计算的重要性,为微观结构演变与应变硬化行为之间的关系提供了新的见解。
An updated Lagrangian computational homogenization framework for large deformation of thin composite beams/shells
Tianyun He, Xiaowei Bai, Qun Huang, Jie Yang, Hamid Zahrouni, Heng Hu
doi:10.1016/j.tws.2025.113999
薄复合梁/壳大变形的改进拉格朗日计算均匀化框架
This paper proposes a novel computational homogenization framework for the an alysis of large rotations and finite strains in thin composite beams/shells. The macroscopic beam/shell is modeled as a continuum beam/shell described by the Kirchhoff shell kinematics (or Euler beam kinematics) within the updated Lagrangian formulation. At the micro-scale, through-thickness representative volume elements (RVEs) are considered and embedded at each integration point of the macroscopic beam/shell via a local co-rotational Cartesian coordinate system, thereby effectively decoupling the microscopic problem from the influence of macroscopic rotations. The RVEs are subjected to in-plane boundary conditions and zero out-of-plane tractions, representing the free top and bottom surfaces. Several numerical examples (e.g., large rotation, finite strain and buckling of thin composite beams and plates) are performed with comparison to the referenced direct numerical simulation. The results demonstrate that the proposed homogenized beam/shell models can accurately and efficiently predict both the macroscopic large deformations and the microscopic stress distributions, e.g., the multi-scale model achieves about 70% efficiency improvement while using the same number of iterations. This paper is believed to provide a powerful computational tool for the an alysis of in-plane periodic thin composite beams/shells.
本文提出了一种新的计算均匀化框架,用于分析薄复合梁/壳的大旋转和有限应变。宏观梁/壳被建模为一个连续体梁/壳,用更新的拉格朗日公式中的基尔霍夫壳运动学(或欧拉梁运动学)来描述。在微观尺度上,通过局部共旋转笛卡尔坐标系,考虑并嵌入通厚代表性体积元(RVEs),从而有效地将微观问题与宏观旋转的影响解耦。rve受面内边界条件和零面外牵引力的约束,代表自由的顶面和底面。对大旋转、有限应变和屈曲等问题进行了数值模拟,并与参考的直接数值模拟进行了比较。结果表明,本文提出的梁/壳均匀化模型能够准确有效地预测宏观大变形和微观应力分布,在相同迭代次数下,多尺度模型的预测效率提高了70%左右。本文为平面内周期性薄复合梁/壳的分析提供了一个强大的计算工具。
Mix vibration control of an elastic beam system with two nonlinear factors
Zheng Li, Yuhao Zhao
doi:10.1016/j.tws.2025.114008
具有两个非线性因素的弹性梁系统的混合振动控制
Given that when nonlinear oscillators are used in the coupling beam system to achieve system vibration control, other nonlinear factors may be introduced due to unfavorable factors such as nonlinear changes in the working characteristics of the connecting devices. At this time, the coupled beam system simultaneously has two nonlinear factors and is affected by their interaction. However, existing research has not explored the influence of the coexistence and interaction of two nonlinear factors on the dynamic behavior of the system. To achieve more comprehensive vibration control of the coupled beam system, this study innovatively proposes a nonlinear mixed control element (NMCE) that incorporates two nonlinear factors. A vibration physical model of a beam system with a nonlinear mixed control system (NMCS) consisting of the NMCE and an additional beam is constructed. Underpinned by the correctness of the calculations, the NMCE’s working characteristics and the dynamic behavior of the beam system influenced by its core parameters are systematically investigated and ana lyzed. The numerical an alysis shows that the NMCE has a significant vibration suppression effect and effectively reduces the vibration amplitude of the extra resonance region. Furthermore, the NMCE has linear and nonlinear work characteristics. It can be found that the nonlinear stiffness of the NMCE leads to the complex nonlinear response of the main beam during vibration, which leads to the targeted energy transfer phenomenon. The nonlinear stiffness combination of the NMCE in the amplitude suppression zone offers an efficient range for parameter selection to attenuate the vibrational response of the beam system. It demonstrates that the introduction of the NMCE provides the possibility for efficient vibration control of beam structures with multiple nonlinear factors in engineering.
考虑到在耦合梁系统中使用非线性振荡器实现系统振动控制时,由于连接装置工作特性的非线性变化等不利因素,可能会引入其他非线性因素。此时,耦合梁系统同时存在两个非线性因素,并受其相互作用的影响。然而,现有的研究尚未探讨两种非线性因素共存和相互作用对系统动力行为的影响。为了实现对耦合梁系统更全面的振动控制,本研究创新性地提出了一种包含两个非线性因素的非线性混合控制单元(NMCE)。建立了由非线性混合控制系统(NMCE)和附加梁组成的非线性混合控制系统梁系统的振动物理模型。在计算正确性的基础上,系统地研究和分析了NMCE核心参数对梁系工作特性和动力行为的影响。数值分析表明,NMCE具有显著的抑振效果,能有效地降低多余共振区的振动幅值。此外,NMCE具有线性和非线性两种工作特性。可以发现,NMCE的非线性刚度导致主梁在振动过程中的复杂非线性响应,从而导致目标能量传递现象。NMCE在幅值抑制区的非线性刚度组合为衰减梁系统的振动响应提供了有效的参数选择范围。结果表明,NMCE的引入为工程中具有多种非线性因素的梁结构的有效振动控制提供了可能。
Development and experimental study of self-centring connections incorporating thin-walled S MA plates for se is mic retrofitting of steel frames
Zeyu Zhou, Xuhong Zhou, Michael C.H. Yam, Yun Huang, Ke Ke
doi:10.1016/j.tws.2025.114011
钢框架抗震加固用薄壁S MA板自定心连接的开发与试验研究
This research reported the development of self-centring connections equipped with thin-walled shape memory alloy plates (S MA-plate connections) for seis mic retrofitting of steel frame structures, where the S MA plates primarily undergo ‘tension-release’ responses to provide moment resistance, self-centring driving force, and energy dissipation for the connection. An experimental study was conducted on four S MA-plate connection specimens to examine their hysteretic behaviour under different loading protocols. In addition, given the limited thickness of the S MA plates commercially available, the feasibility of using double layers of thin-walled S MA plates in the connection was examined in the tests. A hybrid modelling technique for S MA plates was used to conduct numerical simulations of the test results. Design equations were derived to predict the skeleton responses of the specimens. The experimental results demonstrated that the S MA-plate connection specimens exhibited flag-shaped self-centring hysteretic responses within a certain range of deformation. The S MA plates played a key role in achieving satisfactory self-centring performance and stable hysteretic responses, while the configuration of the web connector also affected the residual deformations and energy dissipation capacities. The viability of the double-layer configuration was evidenced by the enhanced strength, stiffness, and energy dissipation. The developed numerical models were capable of reproducing the deformed shapes and hysteresis curves of the specimens. The rationality of the design equations was validated by the good agreement between the predicted skeleton curves and those measured in the tests.
本研究报告了用于钢框架结构抗震加固的配备薄壁形状记忆合金板(S MA-板连接)的自中心连接的发展,其中S MA板主要进行“张力释放”响应,为连接提供力矩阻力,自中心驱动力和能量耗散。对4个s ma板连接试件进行了不同加载方式下的滞回特性试验研究。此外,考虑到市面上可用的S MA板厚度有限,在试验中考察了在连接中使用双层薄壁S MA板的可行性。采用混合建模技术对试验结果进行了数值模拟。推导了设计方程来预测试件的骨架响应。实验结果表明,s ma -板连接试件在一定变形范围内表现出旗形自中心滞回响应。S MA板在获得满意的自定心性能和稳定的滞回响应方面发挥了关键作用,而腹板连接件的配置也影响了残余变形和耗能能力。双层结构的可行性证明了增强的强度,刚度和耗能。所建立的数值模型能够较好地再现试件的变形形状和滞回曲线。预测骨架曲线与试验结果吻合较好,验证了设计方程的合理性。
Assess ment of a thin-web girder bridge subjected to distortion-induced fatigue utilising a vehicle-bridge dynamic interaction methodology based on the Eurocode FLM 4
Ana Célia Soares da Silva, Marilene Lobato Cardoso, Guilherme Santana Alencar, José Guilherme Santos da Silva
doi:10.1016/j.tws.2025.114009
基于欧洲规范flm4的车桥动力相互作用方法对薄壁梁桥变形疲劳的评估
Nowadays, many welded bridges are approaching their design operation life, with various fatigue-related damages becoming increasingly evident. On the other hand, the extensive inventory of highway bridges often necessitates the assess ment of the remaining service life of aging or defective structures, to support the decision about whether to replace or reinforce them. In this context, there is a growing need for reliable methods to predict the fatigue life of welded components and accurately assess their long-term performance under fatigue loading. Thus, a computational tool called VBI (Vehicle-Bridge Interaction) was developed in MATLAB and comprising an interface with the finite element program ANSYS. It is important to emphasize that, while current design codes evaluate welded joints for fatigue life using primarily the Nominal Stress Method (NS M), this research utilises the Hot-spot Stress Method (HS M) for a more accurate definition of stress. In order to illustrate the application of the proposed an alysis methodology, the details of a Finite Element (FE) global numerical model of a typical simply supported steel-concrete composite highway bridge are presented. Different damage scenarios based on the standard vehicle traffic prescribed by EN 1991-2: 2021 (Fatigue Load Model 4) are simulated with the proposed methodology considering the sub modelling technique combined with coarse FE models. An interesting and important structural detail mainly subjected to distortion-induced fatigue is investigated through sub modelling, thus allowing a more realistic approach to evaluate fatigue issues on thin-web girder bridges with typical web-gap details.
目前,许多焊接桥梁已接近设计使用寿命,各种疲劳损伤日益明显。另一方面,公路桥梁的广泛库存往往需要对老化或有缺陷的结构的剩余使用寿命进行评估,以支持是否更换或加固它们的决定。在这种情况下,越来越需要可靠的方法来预测焊接构件的疲劳寿命,并准确评估其在疲劳载荷下的长期性能。因此,在MATLAB中开发了一种计算工具VBI (Vehicle-Bridge Interaction),并与有限元程序ANSYS组成了一个接口。需要强调的是,虽然目前的设计规范主要使用标称应力法(NS M)来评估焊接接头的疲劳寿命,但本研究利用热点应力法(HS M)来更准确地定义应力。为了说明所提出的分析方法的应用,给出了典型简支钢-混凝土组合公路桥梁的有限元整体数值模型。基于en1991 -2: 2021(疲劳载荷模型4)规定的标准车辆交通的不同损伤情景,采用考虑子建模技术与粗有限元模型相结合的提出的方法进行了模拟。通过子模型研究了主要受扭曲疲劳影响的一个有趣而重要的结构细节,从而允许更现实的方法来评估具有典型腹板间隙细节的薄腹板梁桥的疲劳问题。
Eccentric compression behaviour of stainless steel-recycled aggregate concrete-carbon steel double skin tubular (SRCDST) columns
Yukai Zhong, Chengzhang Wu, Yupei Guo, Airong Liu, Jiyang Fu
doi:10.1016/j.tws.2025.114006
不锈钢-再生骨料混凝土-碳钢双皮管(SRCDST)柱的偏心受压性能
This paper presents experimental and numerical studies on the behaviour of stainless steel-recycled aggregate concrete-carbon steel double-skin tubular (SRCDST) columns subjected to eccentric compression. The experimental study included material tests of concrete and steel tubes, measurements of initial global geometric imperfections and eccentric compression tests of twelve SRCDST column specimens, which were designed with varying initial eccentricities, recycled coarse aggregate replacement levels and hollow ratios. The test results of failure loads, deformation responses and failure modes were reported, and the ductility performance, lateral deformation development and longitudinal strain distributions were ana lysed. Finite element models were developed, validated against the experimental data and subsequently employed to conduct parametric studies covering a wide range of geometric dimensions and loading combinations. Three design codes, including Chinese technical specification, European code and American specification, were evaluated for their applicability to eccentrically loaded SRCDST columns against the test and numerical results. The evaluation results generally revealed that the Chinese technical specification offered conservative and slightly scattered failure load predictions for eccentrically loaded SRCDST columns, while the European code resulted in accurate and consistent failure load predictions and the American specification provided accurate predictions but with slight scatter. Finally, a revised design method was proposed based on the Chinese technical specification, demonstrating improved design accuracy and consistency.
本文对不锈钢-再生骨料混凝土-碳钢双皮管(SRCDST)柱在偏心受压作用下的性能进行了试验和数值研究。试验研究包括混凝土和钢管的材料试验、初始整体几何缺陷测量和12个SRCDST柱试件的偏心压缩试验,这些试件设计了不同的初始偏心、再生粗骨料替代水平和空心比。报告了破坏荷载、变形响应和破坏模式的试验结果,分析了其延性、横向变形发展和纵向应变分布。开发了有限元模型,并根据实验数据进行验证,随后用于进行涵盖广泛几何尺寸和加载组合的参数化研究。结合试验结果和数值计算结果,对中国规范、欧洲规范和美国规范3种设计规范对SRCDST偏心受压柱的适用性进行了评价。评价结果普遍表明,中国规范对偏心加载SRCDST柱的破坏荷载预测保守且有轻微的分散,欧洲规范对偏心加载SRCDST柱的破坏荷载预测准确且一致,美国规范对偏心加载SRCDST柱的破坏荷载预测准确但有轻微的分散。最后,提出了一种基于中国技术规范的改进设计方法,提高了设计的准确性和一致性。
Seis mic behavior of concrete-filled steel tube columns strengthened with CFRP grid and ECC
Yuhong Yan, Pengpeng Wang, Dong Zhao, Zhenzhen Liu, Yiyan Lu
doi:10.1016/j.tws.2025.114012
CFRP格栅和ECC加固钢管混凝土柱的抗震性能
This study presents an investigation aim at evaluating the seis mic behavior of concrete-filled steel tube (CFST) columns strengthened with carbon fiber-reinforced polymer (CFRP) grid and engineered cementitious composite (ECC). Ten specimens were fabricated and tested under combined constant axial loads and cyclic lateral loads. The effects of the number of CFRP grid layers, diameter-to-thickness ratio of the steel tube, infilled concrete strength, and axial load ratio on the seis mic behavior of the strengthened columns were an alyzed. The results indicated that the strengthened columns exhibited ductile failure. The CFRP grid and ECC layer significantly prevented the local buckling of the steel tube. Although steel tube deformation at the plastic hinge region was minimal, the crushing of the infilled concrete demonstrated efficient utilization of material strength. After strengthening, the hysteretic curve of the columns became fuller, with lateral load-bearing capacity enhancements ranging from 16.7% to 32.3% and energy dissipation capacity increasing by 58.6%. Increasing the number of CFRP grid layers improved the lateral load-bearing capacity of the strengthened columns but reduced ductility due to more brittle rupture of CFRP. When the axial load ratio was below 0.30, its increase slightly enhanced lateral load-bearing and energy dissipation capacities. However, as the axial load ratio reached 0.45, lateral load-bearing capacity, ductility, and energy dissipation capacity significantly decreased. Considering the confining effects of both the strengthening layer and steel tube on the concrete core, a prediction model for the skeleton curves of the strengthened columns was developed.
本研究旨在评估碳纤维增强聚合物(CFRP)网格和工程胶凝复合材料(ECC)加固钢管混凝土(CFST)柱的抗震性能。制作了10个试件,在恒定轴向载荷和循环侧向载荷联合作用下进行了试验。分析了碳纤维布网格层数、钢管径厚比、填充混凝土强度和轴向荷载比对加固柱抗震性能的影响。结果表明,加固后的柱表现为延性破坏。CFRP格栅和ECC层对钢管的局部屈曲有明显的抑制作用。塑性铰区钢管变形很小,但对混凝土的破坏是材料强度的有效利用。加固后柱的滞回曲线更加饱满,横向承载力提高16.7% ~ 32.3%,耗能能力提高58.6%。增加碳纤维布网格层数提高了加固柱的横向承载能力,但由于碳纤维布脆性断裂的增加而降低了延性。当轴向载荷比小于0.30时,轴向载荷比的增大使其侧向承载能力和耗能能力略有增强。但当轴向载荷比达到0.45时,横向承载能力、延性和耗能能力显著降低。考虑加固层和钢管对混凝土核心的围合作用,建立了加固柱骨架曲线的预测模型。
Dynamic response an alysis of free-span pipelines with strength degradation subjected to underwater explosion
Chenyang Wang, Wei Xiao, Xiongliang Yao, Xiaojian Chen, Hui Wang, Kaixiang Yao
doi:10.1016/j.tws.2025.114013
水下爆炸作用下强度退化的自由跨管道动力响应分析
After the explosion incident of the Nord Stream natural gas pipeline, the safety of free-span pipelines has attracted extensive attention from the international community. However, there are few studies on the problem of pipeline underwater explosion (UNDEX), and the influence of strength degradation caused by vortex-induced vibration (VIV) fatigue damage on the pipeline has been ignored. Based on the strength degradation model and the VIV mechanis m, this study proposes a method for solving the residual strength of three-dimensional free-span pipelines. Taking into comprehensive consideration the fatigue-induced strength degradation of pipelines caused by VIV and the intense impact of UNDEX loads, this study systematically investigates the damage evolution process and deformation behavior of free-span pipelines subjected to UNDEX loading through numerical simulation methods. The results show that VIV fatigue damage can degrade the yield strength of the pipeline with 18 years of service from 448 MPa to 378 MPa. Strength degradation aggravates the structural response to UNDEX loads, and the response rate exhibits exponential growth. In addition, the influence of key factors such as the explosive equivalent, detonation location, and the hydrostatic pressure on the pipeline damage effect is discussed, which provides an important theoretical basis for the blast-resistant design and safety assess ment of free-span pipelines in complex marine environments.
“北溪”天然气管道爆炸事故发生后,自由跨管道的安全问题引起了国际社会的广泛关注。然而,对管道水下爆炸问题的研究较少,且忽略了涡激振动(VIV)疲劳损伤引起的强度退化对管道的影响。基于强度退化模型和振动振动机理,提出了一种求解三维自由跨管道残余强度的方法。综合考虑了管道在VIV作用下的疲劳强度退化和UNDEX荷载的强烈影响,通过数值模拟方法系统研究了自由跨管道在UNDEX荷载作用下的损伤演化过程和变形行为。结果表明:在使用18年的管道中,涡激疲劳损伤会使管道的屈服强度从448 MPa降低到378 MPa;强度退化加剧了结构对UNDEX荷载的响应,且响应率呈指数增长。此外,还讨论了炸药当量、爆轰位置、静水压力等关键因素对管道破坏效果的影响,为复杂海洋环境下自由跨管道的防爆设计和安全评价提供了重要的理论依据。
Dynamic behaviors of engineering-scaled laser-welded pyramid lattice sandwich panels under close-in explosions
Wenhao Wang, Jianhua Dong, Dongyu Shi, Jue Han, Hualin Fan
doi:10.1016/j.tws.2025.114014
近距离爆炸作用下工程尺度激光焊接金字塔格芯板的动力特性
Pyramid lattice sandwich panels (PLSPs) could meet the requirements of lightweight and high resistance, which has significant advantages in defense engineering. This study aims to propose a practical method to manufacture large-scaled PLSPs through laser cutting and welding with dimension over 1.0 m. Stainless steel 2205 with yielding strength of 640 MPa was chosen as the base material to resist strong explosion impacts. The dynamic responses against explosion of PLSPs were investigated via experimental tests and numerical an alyses. For PLSPs in this study, the critical scaled distance is 1.254 m/kg1/3. With the scaled distance decreasing, progressively buckling of the core occurs, followed by compaction, leading to large deformation of PLSPs. Finite element model (FEM) with damping was established, whose maximum displacement prediction error is less than 20%. The energy dissipated by the front face sheet, the lattice core and the back face sheet is close to 20%, over 50% and over 30% of the total energy dissipation, respectively. Compared with solid plate with equal mass, the displacement response of PLSPs shows significant attenuation over 80% in elastic stage over 20% in plastic stage. Meanwhile, PLSPs exhibited s maller deformation compared to other large-scale sandwich panels with close dimensions tested under similar airburst conditions.
金字塔格芯板能够满足轻量化和高阻力的要求,在国防工程中具有显著的优势。本研究旨在提出一种实用的方法,通过激光切割和焊接制造尺寸大于1.0 m的大型PLSPs。选用屈服强度为640mpa的2205不锈钢作为基材,以抵抗强烈的爆炸冲击。通过实验和数值分析,研究了聚苯乙烯聚苯乙烯对爆炸的动态响应。对于本研究的plsp,临界缩放距离为1.254 m/kg1/3。随着尺度距离的减小,岩心逐渐发生屈曲,随后发生压实,导致plsp发生较大变形。建立了带阻尼的有限元模型,最大位移预测误差小于20%。前端面片、点阵芯和后端面片耗散的能量分别接近总耗散的20%、50%以上和30%以上。与等质量实心板相比,plsp的位移响应在弹性阶段衰减80%以上,在塑性阶段衰减20%以上。同时,在类似的空爆条件下,与其他尺寸相近的大型夹层板相比,PLSPs的变形较小。
Benchmarking the Debonding Resistance of Large-Scale Thermal Protection System Composite Panels under Three-Point Bending Using Multi-Camera Digital Image Correlation
Yi Luo, Shibo Yan, Tengfei Xu, Han Liu, Xiquan Zhu, Bing Pan
doi:10.1016/j.tws.2025.114015
利用多相机数字图像相关技术对大型热防护系统复合板三点弯曲下的脱粘阻力进行基准测试
During prolonged atmospheric entry/re-entry of hyper Mach aircraft, maintaining the structural integrity of the thermal protection system (TPS) is of critical importance for safe flight. Large-scale TPSs are subjected to bending loads induced by fuselage flexure and pressure differentials, resulting in bending deformation. TPS debonding from the aircraft may occur when the interfacial stresses induced by structural deformation exceed the bonding load-bearing capacity, severely compromising flight safety. This study conducts a benchmarking experimental investigation on the debonding resistance of aerogel-based and phenolic impregnated carbon ablator (PICA)-based TPS. The debonding resistance of aerogel-based and PICA-based TPS composite panels was quantified and compared through three-point bending tests. Additionally, multi-camera digital image correlation (MC-DIC) was employed to investigate debonding mechanis ms. The comprehensive experiments conclusively establish that aerogel-based TPS composite panels exhibit enhanced debonding resistance to PICA-based TPS composite panels, attributable to the higher bending compliance of aerogel-based TPS composite panels, which mitigates localized strain accumulation and effectively delays debonding initiation. These findings provide crucial insights for optimizing debonding resistance in advanced TPS.
在超长时间进入大气层/再进入大气层时,保持热防护系统的结构完整性对飞行安全至关重要。大型TPSs受到由机身弯曲和压差引起的弯曲载荷,导致弯曲变形。当结构变形引起的界面应力超过粘接承载能力时,TPS可能会从飞机上脱落,严重影响飞行安全。本研究对气凝胶基和酚醛浸渍碳烧蚀(PICA)基TPS的脱粘性能进行了基准实验研究。通过三点弯曲试验对气凝胶基和pica基TPS复合材料板的脱粘抗力进行了量化和比较。此外,采用多相机数字图像相关(MC-DIC)来研究脱粘机制。综合实验结果表明,气凝胶基TPS复合材料板比pica基TPS复合材料板具有更强的抗脱粘能力,这是由于气凝胶基TPS复合材料板具有更高的弯曲顺应性,从而减轻了局部应变积累,有效地延缓了脱粘的发生。这些发现为优化高级TPS的脱粘阻力提供了重要的见解。