【新文速递】2024年12月28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，International Journal of Plasticity 3 篇，Thin-Walled Structures 2 篇

International Journal of Solids and Structures

Programmable wrinkling patterns of liquid crystal network bilayers on compliant substrates

Yifan Yang, Shichen Zhao, Zhijun Dai, Fan Xu

doi:10.1016/j.ijsolstr.2024.113206

柔性基板上液晶网络双层的可编程起皱模式

Smart soft materials have gained increasing attention in recent years because of their adaptive behaviors to external multi-physics stimuli, enabling diverse applications across multiple fields. Here, we show programmable wrinkling morphological patterns on liquid crystal network (LCN) bilayers bonded to compliant substrates under thermal load, by tuning the orientation of directors between LCN bilayers. We propose a solid-shell formulation that merges enhanced and natural assumed strain approaches to investigate the pattern formation and morphological transition of LCN bilayers. By introducing director-determined anisotropic spontaneous strains, we explore effects of director orientations determined by two angles θ (in-plane) and φ (out-of-plane) for each layer, on surface wrinkling pattern formation and evolution. When the directors are aligned in-plane, oblique angles of stripe wrinkles approximates to the average value of director angles in LCN bilayers, i.e., (θ_l+θ_u)/2. For more general spatial alignments of directors, phase diagrams on wrinkling modes indicate that diverse morphologies such as stripe, checkerboard, herringbone and parallel bead-chain modes, can emerge due to intricate nonlinear interactions between bilayers. Pattern selection is found to be primarily determined by the in-plane angle θ, rather than the out-of-plane angle φ. Our results could offer valuable insights into the functional design of smart surfaces related to wrinkling morphology.

近年来，智能软材料因其对外部多物理刺 激的适应性行为而备受关注，这使其在多个领域拥有广泛的应用。在此，我们展示了在热载荷作用下，通过调节液晶网络（LCN）双层膜之间指向矢的方向，在与柔顺基底粘合的 LCN 双层膜上可编程形成褶皱形态图案。我们提出了一种将增强型和自然假设应变方法相结合的固体壳层公式，以研究 LCN 双层膜的图案形成和形态转变。通过引入由指向矢决定的各向异性自发应变，我们探讨了由每层的两个角度 θ（平面内）和 φ（平面外）决定的指向矢方向对表面褶皱图案形成和演变的影响。当指向矢在平面内对齐时，条纹褶皱的倾斜角度近似于 LCN 双层膜中指向矢角度的平均值，即（θ_l + θ_u）/ 2 。对于更普遍的双层膜中分子取向的空间排列，关于起皱模式的相图表明，由于双层膜之间复杂的非线性相互作用，会出现诸如条纹、棋盘格、人字形和平行珠链等多种形态。模式的选择主要取决于平面内角度θ，而非平面外角度φ。我们的研究结果可为与起皱形态相关的智能表面的功能设计提供有价值的见解。

Journal of the Mechanics and Physics of Solids

Coupled large deformation phase-field and cohesive zone model for crack propagation in hard-soft multi-materials

Aimane Najmeddine, Shashank Gupta, Reza Moini

doi:10.1016/j.jmps.2024.106016

硬软复合材料裂纹扩展的大变形相场和内聚区耦合模型

This work presents a unified large deformation constitutive framework that couples the phase-field approach for bulk fracture with the potential-based Park-Paulino-Roesler cohesive zone model (PPR CZM) to study crack propagation in multi-material systems that contain interfaces. The phase-field component captures crack initiation and propagation within bulk constituents, whereas the PPR CZM captures failure mechanisms at interface regions. The proposed unified framework is implemented via a user-element subroutine (UEL) within Abaqus and incorporates a large-deformation extension of the PPR CZM. It was used to examine fracture mechanisms in four scenarios: bi-layer hard-hard composite containing crack impinging on (1) a perpendicular interface and (2) an oblique interface, (3) tri-layer hard-soft multi-material composite containing crack perpendicular to interfaces, and (4) fiber-reinforced matrix composite. Results demonstrated that the unified framework successfully captured crack deflection and penetration in hard-hard bi-layers with dissimilar properties and both perpendicular and oblique interfaces, consistent with Linear Elastic Fracture Mechanics. Furthermore, the large-deformation component of the framework was shown to provide an effective numerical tool for probing the underlying toughening mechanisms in hard-soft multi-material assemblies relative to their monolithic counterparts. Toughening in these composites was characterized by crack bridging and post-peak hardening in the force–displacement response. Finally, the framework accurately predicted complex fracture phenomena in fiber-reinforced composites, involving fiber–matrix debonding (via PPR CZM) and matrix cracking (via phase-field). The framework can inform the design of dissimilar hard-hard brittle materials and hard-soft composites, offering insights into fracture behavior and toughening mechanisms.

本文提出了一个统一的大变形本构框架，将相场方法与基于势的Park-Paulino-Roesler内聚区模型（PPR CZM）相结合，用于研究含有界面的多材料系统中的裂纹扩展。相场分量捕获了块体成分内部裂纹的萌生和扩展，而PPR CZM捕获了界面区域的失效机制。提出的统一框架是通过Abaqus中的用户元素子程序（UEL）实现的，并结合了PPR CZM的大变形扩展。研究了四种情况下的断裂机制：含裂纹撞击(1)垂直界面和(2)斜界面的双层硬-硬复合材料，含裂纹垂直界面的三层硬-软复合材料，以及(4)纤维增强基复合材料。结果表明，统一框架成功捕获了不同性能、垂直和倾斜界面的硬-硬双材料的裂纹挠曲和贯通，符合线弹性断裂力学。此外，框架的大变形组件被证明提供了一个有效的数值工具，用于探测硬-软多材料组件相对于其整体对应物的潜在增韧机制。复合材料的增韧表现为应力-位移响应中的裂纹桥接和峰后硬化。最后，该框架准确预测了纤维增强复合材料的复杂断裂现象，包括纤维-基体脱粘（通过PPR CZM）和基体开裂（通过相场）。该框架可以为不同的硬-硬脆材料和硬-软复合材料的设计提供信息，为断裂行为和增韧机制提供见解。

International Journal of Plasticity

Novel distortional anisotropic hardening model mediated by microstructure evolutions in polycrystalline metals: theory and validation

Seonghwan Choi, Soo-Chang Kang, Jinwoo Lee, Myoung-Gyu Lee

doi:10.1016/j.ijplas.2024.104227

由多晶金属微观结构演变介导的新型畸变各向异性硬化模型：理论与验证

In this study, we introduce a novel anisotropic hardening model designed to capture the macroscopic mechanical responses under complex loading paths while considering the mesoscopic evolutions of crystallographic structures. Based on the framework of homogeneous distortional anisotropic hardening, this model treats the plastic shear strain of each slip system as an internal variable. Utilizing the plastic work equivalence principle, the plastic shear rate within the slip system is determined, aligning with the evolution laws of rate-independent crystal plasticity (CP) theory. The model evaluates the Bauschinger effect and transient hardening at grain level and integrates it into the macroscopic yield function to describe phenomenological hardening responses. The model has been extensively validated against experimental and computational polycrystalline CP approaches, demonstrating its efficacy in capturing both the evolution of crystal textures and complex anisotropic hardening behaviors for both FCC and BCC materials. This proposed hardening model marks a significant advancement in material behavior modeling, effectively bridging the gap between microstructural mechanisms and macroscopic mechanical behavior in better practical way.

在这项研究中，我们引入了一种新的各向异性硬化模型，旨在捕捉复杂加载路径下的宏观力学响应，同时考虑晶体结构的细观演变。该模型基于均匀变形各向异性硬化框架，将各滑移体系的塑性剪切应变作为内部变量。利用塑性功等效原理，根据速率无关晶体塑性理论的演化规律，确定了滑移体系内的塑性剪切速率。该模型评估了包辛格效应和瞬态硬化在晶粒水平上的影响，并将其整合到宏观屈服函数中来描述现象性硬化响应。该模型已经通过实验和计算多晶CP方法进行了广泛的验证，证明了它在捕获FCC和BCC材料的晶体结构演变和复杂的各向异性硬化行为方面的有效性。提出的硬化模型标志着材料行为建模的重大进步，有效地弥合了微观结构机制和宏观力学行为之间的差距，更切合实际。

Bulging of grain boundaries and core-shell dislocation structures enhance mechanical properties of equiatomic high-entropy alloys

Jungwan Lee, Sun Ig Hong, Hyoung Seop Kim

doi:10.1016/j.ijplas.2024.104224

晶界胀形和核壳位错结构提高了等原子高熵合金的力学性能

Regulating elemental compositions of structural materials has been at the heart of interests for metallurgists to ensure target properties under harsh environments. For instance, metastability engineering that exploits phase transformation or deformation twinning depends on a minor modification in atomic compositions. Distinct from the well-studied control of elemental compositions, this work centers on a straightforward thermomechanical process of hot rolling to induce bulging of grain boundaries and core-shell dislocation cell structures. During the hot rolling, the bulging of grain boundaries releases high-density dislocation walls and more dislocations are distributed around the grain boundaries in equiatomic CoCrFeMnNi, one of the most studied high-entropy alloys. Under the tensile deformation at cryogenic temperatures with decreased stacking fault energy, the less stable grain boundaries promote the emanation of partial dislocations and the consequent formation of deformation twinning. As a result, the hot-rolled alloy exhibits an enhanced combination of yield strength of ∼941 MPa and uniform elongation of ∼54% at –196 °C, which is counterintuitive to low ductility of as-rolled metallic materials. This lies at the upper bound in comparison with tensile responses of precipitation-strengthened high-entropy alloys and high-strength steels. The higher propensity of deformation twins in hot-rolled alloy compared to that of cold-rolled and annealed one enhances strain hardening despite the hot-rolled state. Regarding the benefits of the streamlined thermomechanical history, this study validates the academic and industrial worth of hot-rolled metallic materials to develop the alloy science and fabricating technology.

调节结构材料的元素组成一直是冶金学家感兴趣的核心，以确保在恶劣环境下的目标性能。例如，利用相变或变形孪晶的亚稳态工程依赖于原子组成的微小改变。不同于已被充分研究的元素成分控制，这项工作集中在一个直接的热轧热力学过程中，以诱导晶界膨胀和核-壳位错细胞结构。等原子CoCrFeMnNi是研究最多的高熵合金之一，在热轧过程中，晶界的胀形释放出高密度的位错壁，晶界周围分布着更多的位错。在低温拉伸变形下，层错能降低，晶界不稳定，促进了部分位错的发散，从而形成变形孪晶。结果表明，热轧合金在-196℃时屈服强度达到~ 941 MPa，延伸率达到~ 54%，这与轧制时金属材料的低延展性相反。与析出强化高熵合金和高强钢的拉伸响应相比，这是上界。与冷轧和退火合金相比，热轧合金的变形孪晶倾向较高，在热轧状态下强化了应变硬化。考虑到热轧金属材料在热轧过程中所带来的好处，本研究验证了热轧金属材料在合金科学和制造技术发展中的学术和工业价值。

Influences of dislocation configuration and texture optimization on obtaining exceptional cryogenic strength-ductility synergy in a dynamic-recovered heterogeneous high-manganese steel

Hao Xiong, Yu Li, Chun Xu, Wei Li, Xiaoshuai Jia

doi:10.1016/j.ijplas.2024.104225

位错结构和织构优化对动态回收非均相高锰钢获得超常低温强度-塑性协同效应的影响

In this study, an innovative strategy of dislocation configuration and texture optimization is employed to achieve a heterogeneous dynamic-recovered (DRV) high-manganese steel via successive cold-warm-rolling (CWR). Compared with single-step warm-rolling (WR) treatment, the imposed cold deformation of CWR process not only results in more and finer dislocation cells in DRV grains, but also leads to texture optimization with intensity weakening and component changing. Hence, the CWR sample shows a higher yield strength (YS, ∼1.35 GPa) and ultimate tensile strength (UTS, ∼1.6 GPa) without sacrificing the tensile elongation (TEL, ∼57%) at LNT (liquid nitrogen temperature), accompanied with a significantly lower mechanical anisotropy. The exceptional cryogenic strength-ductility synergy can be attributed to following: i) the difference of YS comes from the additional Taylor hardening effect (∼150 MPa); ii) the prefer-orientated DRV grains with a high Schmid factor (SFR) of twinning induces the twin deflections or kinks at the dislocation boundary in the early deformation stage; and iii) the refined cell structure can increase the critical resolved shear stress (CRSS) of twin, act as twin nucleus and impede its growth, leading to the occurrence of high-density of nano-twin segment (thickness: ∼15 nm, number density: ∼1.1*108 m-3) at a high stress and strain level. Thus, the cooperative forest dislocation hardening (∼870 MPa) and dynamic Hall-Petch strengthening (∼220 MPa) effects can provide continuous strain hardening capacity. In contrast, the high ductility of the WR sample primarily originates from the abundant microband-induced plasticity correlated with limited twinning- (TWIP) and transformation-induced plasticity (TRIP) due to a coarse twin (∼22.5 nm) and martensite thickness (∼55 nm).

在本研究中，采用一种创新的位错构型和织构优化策略，通过连续冷温轧制（CWR）实现了高锰钢的非均质动态恢复（DRV）。与单步温轧（WR）处理相比，CWR工艺的冷变形不仅使DRV晶粒中出现了更多更细的位错细胞，而且使织构优化，强度减弱，成分变化。因此，CWR样品在LNT（液氮温度）下表现出更高的屈服强度（YS, ~ 1.35 GPa）和极限抗拉强度（UTS, ~ 1.6 GPa），而不牺牲抗拉伸长率（TEL, ~ 57%），同时力学各向异性显著降低。特殊的低温强度-延性协同作用可归因于以下原因：1)YS的差异来自额外的泰勒硬化效应（~ 150 MPa）；ii)高施密德因子（SFR）的择优取向DRV晶粒在变形初期在位错边界处诱发孪晶挠曲或扭结；精细的胞元结构增加了孪晶的临界分解剪切应力（CRSS），起到孪晶核的作用，阻碍孪晶的生长，导致在高应力应变水平下出现纳米孪晶段高密度（厚度：~ 15 nm，数密度：~ 1.1*108 m-3）。因此，协同森林位错硬化（~ 870 MPa）和动态Hall-Petch强化（~ 220 MPa）效应可以提供连续应变硬化能力。相比之下，WR样品的高延展性主要源于丰富的微带诱导塑性，这与有限的孪晶（TWIP）和由粗孪晶（~ 22.5 nm）和马氏体厚度（~ 55 nm）引起的相变诱导塑性（TRIP）有关。

Thin-Walled Structures

Crashworthiness analysis of bio-inspired multi-order self-similar polymer honeycomb under axial quasi-static and dynamic loading

Chenghao Guo, Xueyu Cheng, Lixin Lu, Liao Pan

doi:10.1016/j.tws.2024.112877

仿生多阶自相似聚合物蜂窝轴向准静态和动态载荷下的耐撞性分析

At present, making the improvement of load-bearing capacity in polymer honeycombs under multi-conditional loading is a critical engineering challenge. To enhance the crashworthiness of polymer honeycomb configurations subjected to quasi-static compression and dynamic impacts, this study proposes a hierarchical strategy, inspired by the cross-sectional structures of horsetail grass and muscle tissue. The hierarchical honeycombs were fabricated using toughened polylactic acid through fused deposition modeling. The load-bearing enhancement mechanism of the hierarchical honeycombs was analyzed using numerical simulations. This strategy reduces the folding wavelength during honeycomb compression, significantly improving cell wall utilization and enhancing energy absorption capacity and stability. Notably, the mean crushing force (MCF) and specific energy absorption (SEA) of the second-order hierarchical honeycomb demonstrate significant enhancements compared to regular honeycomb at the same relative density, with increases of 50.45% and 43.78%, respectively. The third-order hierarchical honeycomb exhibits the excellent energy absorption stability. Under dynamic impacts, the hierarchical honeycombs display an increasingly stable load-bearing process and superior crashworthiness properties with higher hierarchy orders. The MCFs of the hierarchical honeycombs increase significantly with the increase of cell wall thickness. Furthermore, theoretical calculation models incorporating the strain rate effect of the hierarchical honeycombs were developed. The discrepancy between theoretical and experimental results is within 7.5%, confirming the models’ reliability.

目前，如何提高聚合物蜂窝在多条件载荷下的承载能力是一个关键的工程难题。为了提高聚合物蜂窝结构在准静态压缩和动态冲击下的耐撞性，本研究提出了一种分层策略，灵感来自马尾草和肌肉组织的横截面结构。采用增韧聚乳酸熔融沉积模型制备了分层蜂窝。通过数值模拟分析了分层蜂窝的增强承载机理。该策略减少了蜂窝压缩过程中的折叠波长，显著提高了细胞壁利用率，增强了能量吸收能力和稳定性。值得注意的是，在相同相对密度下，二级分层蜂窝的平均破碎力（MCF）和比能吸收（SEA）比普通蜂窝有显著提高，分别提高了50.45%和43.78%。三阶分层蜂窝具有优异的吸能稳定性。在动力冲击下，分层蜂窝结构的承载过程越来越稳定，且随着分层阶数的增加，其耐撞性能也越来越好。分层蜂窝的mcf随细胞壁厚度的增加而显著增加。在此基础上，建立了考虑分层蜂窝应变率效应的理论计算模型。理论与实验结果的偏差在7.5%以内，验证了模型的可靠性。

Pre-compressed beam-based multistable mechanical metamaterials with programmable loading and unloading deformation sequences

Jian Hua, Yuan Zhou, Zhiqiang Meng, Chang Qing Chen

doi:10.1016/j.tws.2024.112879

具有可编程加载和卸载变形序列的基于预压缩梁的多稳定力学超材料

In this work, we propose four types of pre-compressed beam-based multistable mechanical metamaterials and use a combination of theoretical, simulation and experimental methods to systematically explore the effects of pre-compression and initial configurations on their mechanical properties. We found that curved beams with identical initial configurations but different pre-compressions have the same negative stiffness value, but their peak forces differ. Furthermore, the results demonstrate that applying pre-compression is a more effective programming strategy than geometric modulation for altering the stability of the beams. We also demonstrate that pre-compressed multistable mechanical metamaterials can robustly program unloading deformation sequences while maintaining consistent loading orders, thereby enabling the concealment of certain stable configurations. The proposed pre-compressed beam-based mechanical metamaterials offer potential benefits in mechanical computing and information encryption, paving the way for expanding the design concepts and application prospects of multistable mechanical metamaterials.

在这项工作中，我们提出了四种基于预压缩梁的多稳态力学超材料，并采用理论、模拟和实验相结合的方法系统地探索了预压缩和初始配置对其力学性能的影响。研究发现，初始结构相同但预压不同的弯曲梁具有相同的负刚度值，但其峰值力不同。结果表明，采用预压缩比几何调制更有效地改变梁的稳定性。我们还证明了预压缩的多稳定力学超材料可以鲁棒地编程卸载变形序列，同时保持一致的加载顺序，从而实现某些稳定构型的隐藏。提出的基于预压缩梁的机械超材料在机械计算和信息加密方面具有潜在的优势，为扩展多稳态机械超材料的设计理念和应用前景铺平了道路。