【新文速递】2024年2月3日固体力学SCI期刊最新文章

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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 1 篇，Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Experimental analysis and multi-scale simulation of the fracture behavior of polymer-bonded explosives based on the dynamic notched semi-circular bend method

Youcai Xiao, Qiao Zhang, Tianyuan Gong, Yu Zou, Yong Han, Yi Sun

doi:10.1016/j.ijsolstr.2024.112690

基于动态缺口半圆弯曲法的聚合物粘结炸药断裂行为实验分析和多尺度模拟

Polymer-bonded explosives (PBXs) are extensively utilized in both military and civilian applications. Therefore, an accurate measurement of their dynamic fracture properties is critical for ensuring the safety and stability in engineering applications. In this study, a split Hopkinson pressure bar (SHPB) loading system is utilized to conduct dynamic fracture tests on a notched semi-circular bend (NSCB) specimen. A crack propagation gauge (CPG) and a strain gauge (SG) are employed for capturing the transient crack propagation velocity, crack initiation, and unstable propagation at a specific moment. The dynamic fracture behavior of PBX-9001 can be categorized into three stages. To acquire the damage evolution data during loading, a finite element model based on the real crystal morphology, with a cohesive zone model (CZM) for describing the damage, is developed. Additionally, a multi-scale simulation model has been established to investigate the microscopic damage and degree of damage in PBX-9001. The microstructure of PBX-9001 exhibits toughening effects, and the initiation toughness and extension toughness are positively correlated with the loading rate. The multi-scale model effectively simulates the expansion behavior and damage evolution of PBX-9001. Overall, the findings of this study provide useful insights on the nonlinear fracture behavior and the influence of loading rate on the mesoscopic fracture mechanisms of PBXs.

聚合物粘结炸药（PBX）被广泛应用于军事和民用领域。因此，精确测量其动态断裂特性对于确保工程应用的安全性和稳定性至关重要。在本研究中，利用分体式霍普金森压力棒（SHPB）加载系统对缺口半圆形弯曲（NSCB）试样进行了动态断裂测试。采用裂纹扩展仪（CPG）和应变仪（SG）捕捉特定时刻的瞬态裂纹扩展速度、裂纹起始和不稳定扩展。PBX-9001 的动态断裂行为可分为三个阶段。为了获取加载过程中的损伤演变数据，开发了一个基于真实晶体形态的有限元模型，并使用内聚区模型（CZM）来描述损伤。此外，还建立了一个多尺度模拟模型来研究 PBX-9001 的微观损伤和损伤程度。PBX-9001 的微观结构表现出增韧效应，起始韧度和扩展韧度与加载速率呈正相关。多尺度模型有效地模拟了 PBX-9001 的膨胀行为和损伤演变。总之，本研究的结果为非线性断裂行为以及加载速率对 PBX 中观断裂机制的影响提供了有益的启示。

Journal of the Mechanics and Physics of Solids

A general mechanism for long-range friction modulation in graphene-based moiré heterostructures

Ke Huang, Yilun Liu

doi:10.1016/j.jmps.2024.105560

石墨烯基摩尔纹异质结构中长程摩擦调制的一般机制

The moiré scale friction modulation is a well-known phenomenon for tip sliding on van der Waals heterostructures. In this study, we have discovered a general rule that governs the long-range friction modulation in graphene-based moiré heterostructures. Firstly, the moiré in-plane lattice reconstruction regulates out-of-plane moiré morphology. Secondly, the in-plane deformation of graphene induced by tip sliding on the reconstructed moiré surface can significantly amplify the local movement of the moiré surface. Thirdly, the out-of-plane morphology and local movement of the moiré surface change the contact trajectory of the tip, thereby modulating the moiré scale friction. As the moiré reconstruction is closely related to the stacking status of heterostructures, an explicit expression of the reconstructed moiré morphology is derived based on the local registry index. Then, the tip contact trajectory is obtained by considering the tip indentation and in-plane deformation-induced moiré patterns movement for twisted and strained graphene heterostructures. Based on the tip contact trajectory, the long-range friction modulation of graphene heterostructures is perfectly characterized. Furthermore, a deformation-coupled Prandtl-Tomlinson model was developed, which well reproduces the friction behaviors of graphene-based moiré heterostructures. Our findings highlight the crucial role of internal dynamics of contact interfaces on frictional behaviors of van der Waals (vdW) moiré superlattices, offering valuable insights for the rational design and control of frictional response at the nanoscale.

摩尔尺度摩擦调制是范德华异质结构上尖端滑动的一种众所周知的现象。在这项研究中，我们发现了支配石墨烯基摩尔纹异质结构长程摩擦调制的一般规律。首先，摩尔纹面内晶格重构调节面外摩尔纹形态。其次，尖端在重构摩尔纹表面上滑动所引起的石墨烯平面内变形会显著放大摩尔纹表面的局部运动。第三，摩尔纹表面的平面外形态和局部运动会改变针尖的接触轨迹，从而调节摩尔纹尺度摩擦。由于摩尔纹重构与异质结构的堆叠状态密切相关，因此根据局部注册指数推导出了重构摩尔纹形态的明确表达式。然后，通过考虑扭曲和应变石墨烯异质结构的尖端压痕和平面内形变引起的摩尔纹运动，得到了尖端接触轨迹。根据尖端接触轨迹，完美地描述了石墨烯异质结构的长程摩擦调制。此外，我们还建立了一个变形耦合普朗特-汤林森模型，该模型很好地再现了基于石墨烯的莫伊里纹异质结构的摩擦行为。我们的研究结果凸显了接触界面的内部动力学对范德华（vdW）莫雷超晶格摩擦行为的关键作用，为合理设计和控制纳米尺度的摩擦响应提供了宝贵的见解。

International Journal of Plasticity

Quantifying contribution of hierarchically correlated shear microdomains underlying creep in metallic glass

F. Zhu, G.H. Xing, Yun-Jiang Wang, E. Pineda, J.C. Qiao

doi:10.1016/j.ijplas.2024.103900

量化分层关联剪切微域对金属玻璃蠕变的贡献

Investigation of the strain evolution of a Cu46Zr47Al7 metallic glass (MG) was conducted through creep deformation encompassing various temperature and stress conditions. The fundamental framework of atomic motion was established through hierarchically dynamic correlation. By discerning a transition in strain rate from three to two regions under cyclic loading conditions, we effectively identified the two underlying mechanisms of creep. The initial deformation mechanism is associated with τ-defects (shear microdomains, SMDs) characterized by a high degree of atomic correlation. This mechanism entails both reversible deformation within a short temporal span and irreversible deformation over an extended duration. Remarkably, the atomic correlation of SMDs remains nearly unaffected by variations in stress and temperature. Furthermore, a fundamental intrinsic correlation emerges between the atomic correlation of SMDs and the defect concentration as ascertained through the framework of quasi-point defect (QPD) theory. The second deformation mechanism entails irreversible deformation attributed to structural relaxation, exhibiting a relatively diminished atomic correlation. In this mechanism, the correlation of atomic motion exhibits a decline with rising temperatures, while remaining relatively less influenced by mechanical effects. Meanwhile, after annealing treatment, the deformation strength associated with structural relaxation significantly decreases. Our study sheds light on the underlying mechanisms of creep in MGs, compensates for the shortcomings of QPD theory in describing long-term creep and provides insights into the fundamental atomic-scale processes governing the mechanical behavior of MGs.

通过在各种温度和应力条件下进行蠕变变形，研究了 Cu46Zr47Al7 金属玻璃 (MG) 的应变演变。通过分层动态关联建立了原子运动的基本框架。在循环加载条件下，应变率从三个区域过渡到两个区域，通过这一过程，我们有效地确定了蠕变的两种基本机制。最初的变形机制与τ缺陷（剪切微域，SMD）有关，其特征是高度的原子相关性。这种机制既包括短时间内的可逆变形，也包括长时间内的不可逆变形。值得注意的是，SMD 的原子相关性几乎不受应力和温度变化的影响。此外，通过准点缺陷（QPD）理论框架确定，SMD 的原子相关性与缺陷浓度之间存在基本的内在相关性。第二种变形机制是结构松弛引起的不可逆变形，表现出相对减弱的原子相关性。在这一机制中，原子运动的相关性随着温度的升高而下降，同时受机械效应的影响相对较小。同时，经过退火处理后，与结构松弛相关的变形强度显著降低。我们的研究揭示了 MGs 蠕变的内在机理，弥补了 QPD 理论在描述长期蠕变方面的不足，并对支配 MGs 力学行为的基本原子尺度过程提供了见解。

Thin-Walled Structures

An interpolatory basis lumped mass isogeometric formulation with rigorous assessment of frequency accuracy for Kirchhoff plates

Xiwei Li, Songyang Hou, Dongdong Wang

doi:10.1016/j.tws.2024.111639

基于插值的块状质量等距计算方法，对基尔霍夫板的频率精度进行严格评估

A noticeable drawback associated with the isogeometric free vibration analysis of Kirchhoff plates with lumped mass formulation is that its frequency accuracy is strongly limited to 2nd order, no matter what degrees of basis functions are used. This issue is resolved herein by a lumped mass isogeometric formulation using a set of interpolatory basis functions. These interpolatory basis functions are constructed via transforming the standard isogeometric basis functions with respect to the Greville nodes. A direct consequence of the basis interpolation property is that the resulting lumped mass matrices can be realized with a nodal integration technique, and the corresponding nodal quadrature rules are then developed for cubic and quartic basis functions. Furthermore, based upon the transformation relationship between the standard and interpolatory basis functions, a frequency equivalence is rationally established between the standard and transformed isogeometric formulations, which enables a rigorous analytical study of the frequency accuracy for the proposed approach. In particular, the theoretical frequency error estimates are obtained for both cubic and quartic basis functions, which clearly illustrate the frequency accuracy superiority of the proposed method over the standard lumped mass isogeometric formulation for Kirchhoff plates. The theoretical observations are simultaneously demonstrated by numerical results.

基尔霍夫（Kirchhoff）板的等距自由振动分析中，一个明显的缺点是，无论使用何种程度的基函数，其频率精度都严重受限于二阶。本文通过使用一组插值基函数的整块质量等距公式解决了这一问题。这些插值基函数是通过对标准等距测量基函数进行格雷维尔节点变换而构建的。基函数插值特性的一个直接结果是，由此产生的块状质量矩阵可以通过节点积分技术实现，然后为三次基函数和四次基函数制定相应的节点正交规则。此外，根据标准基函数和插值基函数之间的变换关系，合理地建立了标准等距公式和变换等距公式之间的频率等价关系，从而可以对所提出方法的频率精度进行严格的分析研究。特别是，对三次基函数和四次基函数都得到了理论频率误差估计值，这清楚地说明了所提方法的频率精度优于基尔霍夫板的标准块状质量等距公式。数值结果也同时证明了上述理论观点。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年1月23日固体力学SCI期刊最新文章

今日更新：Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇Journal of the Mechanics and Physics of SolidsA continuous phase-evolution model for cold and strain-induced crystallization in semi-crystalline polymersMing Lei, Shuailong Ren, Yulin Xiong, Jinyou Xiao, Lihua Wen, Haibao Lu, Xiao Houdoi:10.1016/j.jmps.2024.105550半结晶聚合物中低温和应变诱导结晶的连续相演化模型The dynamic crystallization during extreme thermomechanical history under producing or service strongly influences the dimensional stability of the semi-crystalline thermoplastic polymers. To produce high-precision structural components, the proper thermomechanical history needs to be carefully designed to eliminate the crystallization-induced shrinkage. On the contrary, the rapidly developed four-dimensional (4D) printing technology tries to amplify the crystallization-induced shrinkage to directly produce the complex curvatures without supporting materials. However, the crystals formed at different deformation states might have different orientations, leading to an anisotropic residual deformation. Therefore, tracing of all crystals formed with different initial configurations is the key issue to ensure the geometric accuracy of both the high-precision and the deformable components. In this study, we developed a continuous phase-evolution model for both the cold and the strain-induced crystallization in semi-crystalline thermoplastics. The irreversible cold crystallization is analogized as the raindrop falling into the pool, and the reversible strain-induced crystallization is analogized as the nonequilibrium liquid-gas phase transformation. Using the continuous phase-evolution concept, the crystal growth is described by a series of continuously formed crystal phases sequentially added into the initial amorphous medium. Each newly formed crystal phase is in a stress-free state at the formation moment, and therefore the crystallization history coupled with the whole deformation history can be memorized. By introducing the oriented growth tensor representing the stress-free state of all formed crystals, the deformation-history dependent anisotropic crystallization and the corresponding residual deformation can be traced. The developed model is validated by comparing with the experimental data of the dynamic crystallization in amorphous poly l-lactide polymers under thermomechanical loading cycles. Finally, the predictive capability of the model is illustrated by several demonstrations, to show the influences of deformation-history dependent crystallization orientations and the corresponding anisotropic residual deformation.在生产或使用过程中，极端热机械过程中的动态结晶对半结晶热塑性聚合物的尺寸稳定性有很大影响。为了生产高精度的结构部件，需要仔细设计适当的热机械历史，以消除结晶引起的收缩。相反，快速发展的四维(4D)打印技术试图放大结晶引起的收缩，直接产生复杂的曲率，而不需要支撑材料。然而，在不同变形状态下形成的晶体可能具有不同的取向，导致各向异性残余变形。因此，以不同初始构型形成的所有晶体的示踪是保证高精度和可变形部件几何精度的关键问题。在这项研究中，我们建立了半结晶热塑性塑料的冷结晶和应变诱导结晶的连续相演化模型。不可逆冷结晶被类比为雨滴落入池中，可逆应变结晶被类比为非平衡气液相变。利用连续相演化的概念，晶体生长是通过一系列连续形成的晶体相依次加入到初始非晶介质中来描述的。每个新形成的晶相在形成时刻都处于无应力状态，因此可以记忆结晶历史和整个变形历史。通过引入代表所有形成的晶体无应力状态的取向生长张量，可以追踪变形历史相关的各向异性结晶和相应的残余变形。通过与热载荷作用下非晶态聚l-丙交酯聚合物动态结晶实验数据的对比，验证了所建立的模型的有效性。最后，通过几个实例说明了该模型的预测能力，以显示变形历史相关的结晶取向和相应的各向异性残余变形的影响。Mechanics of MaterialsEmerging anisotropy and tethering with memory effects in fibrous materialsAntonino Favata, Andrea Rodella, Stefano Vidolidoi:10.1016/j.mechmat.2024.104928 纤维材料中出现的各向异性和记忆效应Fibrous materials may undergo an internal reorganization, which turns out in the emergence of preferential directions. This is a peculiar behavior of many biological tissues, which drive reorientation by external stimuli at chemo-mechanical levels. In particular, it is detected that contractile cells can reorganize fibrous extracellular matrices and form dense tracts of aligned fibers (tethers), that guide the development of tubular tissue structures and may provide paths for the invasion of cancer cells. Tether formation is caused by buckling instability of network fibres under cell-induced compression. We present a simple mechanical model within a variational framework that captures the essential aspects of these phenomena. The model qualitatively describes: (i) the emergence, induced by local compressive strain, of anisotropy, where fibrous materials exhibit directional preferences; (ii) the occurrence of micro-buckling, which leaves a lasting plastic deformation in the material; and (iii) the formation of localized field patterns, which contribute to the overall behavior of the material. By considering these fundamental aspects, our model provides insights into the mechanical response of fibrous materials and sheds light on the underlying mechanisms driving their behavior.纤维材料可能经历内部重组，这表现为优先方向的出现。这是许多生物组织的一种特殊行为，它在化学机械水平上通过外部刺激驱动重新定向。特别是，研究发现，收缩细胞可以重组纤维细胞外基质，形成密集的排列纤维束(系索)，引导管状组织结构的发展，并可能为癌细胞的侵袭提供途径。绳系的形成是由网状纤维在细胞诱导的压缩作用下的屈曲失稳引起的。我们在变分框架内提出一个简单的力学模型，该模型捕捉了这些现象的基本方面。该模型定性地描述了:(i)由局部压缩应变引起的各向异性的出现，其中纤维材料表现出方向偏好;(ii)发生微屈曲，在材料中留下持久的塑性变形;(iii)局部场模式的形成，这有助于材料的整体行为。通过考虑这些基本方面，我们的模型提供了对纤维材料的机械响应的见解，并阐明了驱动其行为的潜在机制。来源：复合材料力学仿真Composites FEM