【新文速递】2024年7月21日固体力学SCI期刊最新文章

 

今日更新：International Journal of Solids and Structures 1 篇，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 3 篇

International Journal of Solids and Structures

Torsional buckling of a tape-spring: Review and renew

J.A. Clarkson, K.A. Seffen

doi:10.1016/j.ijsolstr.2024.112992

带式弹簧的扭转屈曲:回顾与更新

Tape-springs—straight strips with transversely curved cross-sections—undergo a flattening of the cross-section upon bending, and accompanying torsional buckling in equal-sense bending which then “recedes” at greater deformation. The exact analytical solution for tape-spring bending was solved by Mansfield; however, the resulting expression for the twisting curvature at the onset and recession of torsional buckling cannot be solved in closed-form. Approximate closed-form expressions are therefore sought: firstly, by utilising Taylor series approximations of Mansfield’s extensive functions; and secondly, by assuming a uniform transverse curvature, thereby rendering the problem algebraic in nature, and deriving new governing expressions. Further approximations assume the cross-section does not deform upon bending, and that the tape-spring remains a developable surface in the inextensible limit of zero thickness. All approximate soluions are shown to agree closely with Mansfield’s solution at small curvatures, with the uniform curvature approximation also capturing the recession of torsional buckling to a reasonable degree of accuracy. The accuracy of the uniform curvature approximation is related to a pertinent dimensionless parameter, which governs the size of a boundary layer in Mansfield’s exact solution: as this parameter tends to infinity, the uniform curvature approximation and Mansfield’s exact solution are shown to converge; as it tends to zero, all solutions are shown to converge on the inextensible limit.

带式弹簧——横弯曲截面的直条——在弯曲时经历横截面的变平，并伴随等意义弯曲的扭转屈曲，然后在更大的变形下“后退”。曼斯菲尔德给出了带簧弯曲的精确解析解;然而，得到的扭转屈曲起始和消退时的扭转曲率表达式不能用封闭形式求解。因此，寻求近似的封闭形式表达式:首先，利用曼斯菲尔德广义函数的泰勒级数近似;其次，通过假设一个均匀的横向曲率，从而使问题具有代数性质，并推导出新的控制表达式。进一步的近似假设截面在弯曲时不变形，并且带式弹簧在零厚度的不可扩展极限下仍然是一个可展表面。在小曲率下，所有近似解都与曼斯菲尔德解非常吻合，均匀曲率近似也以合理的精度捕捉了扭转屈曲的衰退。均匀曲率近似的精度与一个相关的无量纲参数有关，该参数决定了曼斯菲尔德精确解中边界层的大小:当该参数趋于无穷大时，均匀曲率近似和曼斯菲尔德精确解显示为收敛;当它趋于零时，所有解都收敛于不可扩展极限。

Mechanics of Materials

Iterated learning and multiscale modeling of history-dependent architectured metamaterials

Yupeng Zhang, Kaushik Bhattacharya

doi:10.1016/j.mechmat.2024.105090

历史相关建筑超材料的迭代学习和多尺度建模

Neural network based models have emerged as a powerful tool in multiscale modeling of materials. One promising approach is to use a neural network based model, trained using data generated from repeated solution of an expensive small scale model, as a surrogate for the small scale model in application scale simulations. Such approaches have been shown to have the potential accuracy of concurrent multiscale methods like FE2, but at the cost comparable to empirical methods like classical constitutive models or parameter passing. A key question is to understand how much and what kind of data is necessary to obtain an accurate surrogate. This paper examines this question for history dependent elastic–plastic behavior of an architected metamaterial modeled as a truss. We introduce an iterative approach where we use the rich arbitrary class of trajectories to train an initial model, but then iteratively update the class of trajectories with those that arise in large scale simulation and use transfer learning to update the model. We show that such an approach converges to a highly accurate surrogate, and one that is transferable.

基于神经网络的模型已成为材料多尺度建模的有力工具。一种很有前途的方法是使用基于神经网络的模型，该模型是利用重复求解昂贵的小尺度模型所产生的数据训练而成的，在应用尺度模拟中作为小尺度模型的替代物。这种方法已被证明具有 FE2 等并行多尺度方法的潜在精度，但成本却与经典构造模型或参数传递等经验方法相当。一个关键问题是了解需要多少数据和哪种数据才能获得准确的代用数据。本文针对建模为桁架的建筑超材料的历史相关弹塑性行为研究了这一问题。我们引入了一种迭代方法，即使用丰富的任意轨迹类别来训练初始模型，然后用大规模模拟中出现的轨迹类别迭代更新轨迹类别，并使用迁移学习来更新模型。我们的研究表明，这种方法可以获得高精度的代用模型，而且是可迁移的。

International Journal of Plasticity

The development of grain resolved stress fields around notch tips in soft-textured zirconium polycrystals: A three-dimensional synchrotron X-ray diffraction study

Karim Louca, Katherine S. Shanks, Amlan Das, Darren Pagan, Robert Klassen, Hamidreza Abdolvand

doi:10.1016/j.ijplas.2024.104076

软织构锆多晶缺口尖端处晶粒分辨应力场的发展:三维同步x射线衍射研究

Texture, microstructure, and local grain neighbourhood contribute to the development of localized stresses in polycrystals. For hexagonal close-packed materials, crystal's elastic and plastic anisotropy can also be a major contributing factor, yet there is a paucity of experimental studies focusing on the extent of contribution of such parameters on the magnitude of localized stresses at microscales. This study focuses on addressing this knowledge gap by deforming double-edge-notched soft-textured α-zirconium specimens in-situ, while measuring grain scale tensorial stresses using high energy synchrotron X-ray diffraction. The specimens were subjected to cyclic loads to study the evolution of stresses in the vicinity of both shallow and deep notches. The soft-texture of the specimens is such that there are no c-axes of grains aligned along the macroscopic loading direction thereby inhibiting deformation twinning. The “as-measured” microstructures and notch geometries were imported into a crystal plasticity finite element model for further analysis. Results show that despite the absence of c-axes of grains aligned along loading direction, the developed stresses were substantially influenced by crystallographic orientations. Stress drop was observed near the onset of plasticity with further loading and the orientation and position effects were highlighted. A plastic deformation mechanism was revealed where, upon specimen loading, the mechanical constraints enforced during grain-grain interactions led to hardening. Accordingly, a parameter was devised to quantify the grain level hardening arising from this mechanism. It was shown that grain-scale stress concentration factors vary significantly before the onset of plasticity, but they settle in the plastic zone and with the progression of cycles.

织构、微观结构和局部晶粒邻域对多晶局部应力的产生有重要影响。对于六方密排材料，晶体的弹塑性各向异性也可能是一个主要的影响因素，但在微观尺度上，这些参数对局部应力大小的影响程度的实验研究较少。本研究主要通过原位变形双棱缺口软织构α-锆试样，同时利用高能同步x射线衍射测量晶粒尺度张应力来解决这一知识空白。在循环荷载作用下，研究了浅切口和深切口附近的应力演化规律。试样的软织构使得晶粒不存在沿宏观加载方向排列的c轴，从而抑制了变形孪晶。将“实测”的显微组织和缺口几何形状输入到晶体塑性有限元模型中进行进一步分析。结果表明，尽管没有沿加载方向排列的晶粒c轴，但发育的应力很大程度上受晶体取向的影响。随着进一步加载，在塑性开始附近观察到应力下降，并突出了取向和位置效应。在试样加载时，晶粒相互作用过程中施加的机械约束导致硬化，揭示了塑性变形机制。因此，设计了一个参数来量化由该机制引起的晶粒级硬化。结果表明:在塑性开始前，晶粒级应力集中系数有显著变化，但随着循环的进行，应力集中系数在塑性区趋于稳定;

Thin-Walled Structures

Cumulative damage effects of repeated underwater explosions on multi-cabin structures

Lele Cheng, Fenglei Huang, Haijun Wu, Heng Dong, Sichen Tian

doi:10.1016/j.tws.2024.112231

水下重复爆炸对多舱结构的累积损伤效应

This paper presents experimental and numerical findings regarding complex multi-cabin structures with the goal of elucidating cumulative damage mechanisms and assessing the influence of blast distance on damage characteristics under repeated underwater explosions. The damage characteristics of a multi-cabin structure were analyzed through single and repeated explosion tests employing equal-mass charges. The shockwave loads and structural damage observed during testing were accurately predicted through numerical simulations, which revealed that the structure experienced the combined impact of shockwaves, transmitted pressure waves, and bubble expansion loads during repeated explosions. The findings demonstrate that repeated underwater explosions produce a cumulative damage effect, leading to a significant increase in the extent of depression plastic deformation and deflection of the structure. However, the gain in cumulative damage effects is limited compared to a single explosion with an equivalent charge. A single explosion results in extensive tearing and dent deformation of the structure, causing far more severe damage than repeated explosions.

本文针对复杂多舱结构进行了实验和数值研究，旨在阐明水下重复爆炸作用下的累积损伤机理，并评估爆炸距离对损伤特性的影响。通过等质量装药的单次和多次爆炸试验，分析了某多舱结构的损伤特性。通过数值模拟准确预测了试验中观察到的冲击波载荷和结构损伤，揭示了结构在重复爆炸过程中受到冲击波、传递压力波和气泡膨胀载荷的综合影响。研究结果表明，反复水下爆炸会产生累积损伤效应，导致结构的凹陷塑性变形和挠曲程度显著增加。然而，累积伤害效果的增益与同等装药的单次爆炸相比是有限的。单次爆炸会导致结构的广泛撕裂和凹痕变形，造成的破坏远比多次爆炸严重。

Geometrically nonlinear topology and fiber orientation optimization of composite structures using membrane-embedded model

Wenjie Zuo, Xinyu Xie, Ran Zhang, Yuyuan Lu, Tao Tang, Lijia An, Jiantao Bai

doi:10.1016/j.tws.2024.112250

基于膜嵌入模型的复合材料结构几何非线性拓扑和纤维取向优化

The membrane-embedded model can be efficiently used in the finite element analysis of composite structures considering geometrical nonlinearity because of its practicability. This paper extends this model to the topology and fiber orientation optimization considering geometrical nonlinearity. The discrete design variables of topology and fiber orientation are continuous by the solid isotropic material with penalization method and bi-value coding parameterization method. An optimized interpolation scheme for the membrane-embedded model is constructed for geometrical nonlinearity. The filtering function is added to improve the convergence of the fiber orientation. To reduce the computational complexity, topology and fiber orientation are independently updated at each iteration during the optimization process. Numerical examples demonstrate the effectiveness of the proposed method for membrane-embedded composite considering geometrical nonlinearity.

膜嵌模型具有实用性，可有效地用于考虑几何非线性的复合材料结构的有限元分析。本文将该模型推广到考虑几何非线性的拓扑优化和光纤定向优化。固体各向同性材料采用惩罚法和双值编码参数化方法，使拓扑和纤维取向的离散设计变量连续化。针对几何非线性，构造了一种优化的膜嵌模型插值方案。增加了滤波功能，提高了光纤方向的收敛性。在优化过程中，每次迭代都独立更新拓扑和光纤方向，以降低计算复杂度。数值算例验证了该方法对考虑几何非线性的膜嵌复合材料的有效性。

In-plane crashing behavior and energy absorption of graded re-entrant honeycomb reinforced by catenary

Zhen Zou, Fengxiang Xu, Xiaoqiang Niu, Chong Xie, Tengyuan Fang

doi:10.1016/j.tws.2024.112253

接触网增强梯度再入蜂窝的面内碰撞行为及能量吸收

Re-entrant honeycombs have demonstrated promising applications in engineering fields attributed to better manufacturability and adaptability. Herein, the reinforced re-entrant honeycombs (RRH) with thickness and reinforced strut gradients are proposed, respectively, and their in-plane energy absorption is investigated through experiment, theoretical analysis, and simulation. Metallic specimens of uniform and graded RRH are manufactured through a step-by-step method. The deformation mode and plateau stress (PS) of these specimens are significantly influenced by both thickness and catenary gradients. Two PSs of RRH specimens are predicted theoretically with a relative error of less than 7.0%. Subsequently, the deformation mode and energy absorption of uniform and graded RRH, subjected to varying load rates, are investigated thoroughly with a numerical method verified against the experimental data. The results show that both thickness and catenary gradients can inspire multi-step deformation mode and prevent instability deformation. Compared to uniform RRH (U-RRH), the specific energy absorptions (SEA) of thickness gradient (TG)-123 (123 represents that the thicknesses from impact end to fixed end are t1, t2, t3) and TG-213 are enhanced by 52.2% and 49.8%, respectively, under quasi-static compression, the SEA of TG-132 and TG-123 are raised by 41.6% and 20.2%, respectively, under low-velocity impact, and the SEA of strut gradient (SG)-123 is 66.7% higher than that of U-RRH under high-velocity impact. More significant auxetic deformation does not always mean better energy absorption because there is also an increased tendency of global instability and earlier densification points. This work provides a novel approach to designing high-energy absorption honeycombs with low structural complexity.

由于具有更好的可制造性和适应性，再入式蜂窝在工程领域有着广阔的应用前景。本文分别提出了具有厚度梯度和加强支杆梯度的加强型再入蜂窝（RRH），并通过实验、理论分析和仿真研究了其平面内的能量吸收。通过分步法制作了均匀和分级 RRH 的金属试样。这些试样的变形模式和高原应力（PS）受厚度和导管梯度的影响很大。对 RRH 试样的两个 PS 进行了理论预测，相对误差小于 7.0%。随后，通过数值方法与实验数据进行验证，深入研究了均匀和分级 RRH 在不同荷载速率下的变形模式和能量吸收。结果表明，厚度梯度和导管梯度都能激发多级变形模式，防止不稳定变形。与均匀 RRH（U-RRH）相比，厚度梯度（TG）-123（123 表示从冲击端到固定端的厚度分别为 t1、t2、t3）和 TG-213 的比能量吸收（SEA）分别提高了 52.2% 和 49. 在准静态压缩下，TG-132 和 TG-123 的 SEA 分别提高了 52.2% 和 49.8%；在低速冲击下，TG-132 和 TG-123 的 SEA 分别提高了 41.6% 和 20.2%；在高速冲击下，支柱梯度（SG）-123 的 SEA 比 U-RRH 高 66.7%。更明显的辅助变形并不总是意味着更好的能量吸收，因为全局不稳定性和更早的致密化点的趋势也会增加。这项工作为设计结构复杂度低的高能量吸收蜂窝提供了一种新方法。