【新文速递】2024年1月19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，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 2 篇

International Journal of Solids and Structures

Sub-preferential rotational wave beaming in structurally rhombus re-entrant honeycombs

ZhiWei Zhu, ZiChen Deng

doi:10.1016/j.ijsolstr.2024.112666

结构菱形再入式蜂窝的亚优先旋转波束

Rotational waves frequently manifest in micro-structured materials and are often coupled with classical shear or longitudinal wave modes. In this study, a distinctive isolated optical branch, exhibiting very high polarization index related to joint rotation motion, is found in dispersion diagram of elastic wave propagation in structurally rhombus re-entrant honeycomb (SSRH). Through an analysis of group velocity, we further explore the wave beaming of the rotational wave propagation within the SRRH, and intriguingly, observe the emergence of sub-preferential wave beaming occurring along the short diagonal directions. This dynamic anisotropic phenomenon stems from the intricate interplay between wave frequency and structural topology. To elucidate the underlying dynamic anisotropy of rotational waves, we propose a simple rigid-spring model and derive a modulation function that precisely captures the intricate frequency-structure coupling behavior. The obtained modulation function unveils the formation of sub-preferential directions of the rotational wave within the SRRH.

旋转波经常出现在微结构材料中，并且经常与经典的剪切波或纵波模式耦合。本研究在结构菱形重入蜂窝(SSRH)弹性波传播色散图中发现了一个独特的孤立光学分支，该分支与关节旋转运动相关，具有很高的偏振指数。通过对群速度的分析，我们进一步探讨了旋转波在SRRH内传播的波束，有趣的是，我们观察到沿短对角线方向出现了亚优先波束。这种动态各向异性现象源于波频和结构拓扑之间复杂的相互作用。为了阐明旋转波潜在的动态各向异性，我们提出了一个简单的刚性-弹簧模型，并推导了一个精确捕捉复杂频率-结构耦合行为的调制函数。得到的调制函数揭示了SRRH内旋转波亚优先方向的形成。

Journal of the Mechanics and Physics of Solids

Elastic fields of double branched and Kalthoff–Winkler cracks in a half-plane

Yangjian Si, Yujie Wei

doi:10.1016/j.jmps.2024.105546

半平面上双分支和Kalthoff-Winkler裂纹的弹性场

We demonstrate in this paper a combination of the Schwarz-Christoffel mapping and Muskhelishvili’s approach with fractional function series in solving the elastic fields of a cracked half-plane, and zoom in on two typical problems, a double branched crack with two rays emanating from one point on the edge and two edge cracks spaced by a certain distance. Typical loading conditions are considered, including far-field uniform tensile stress and concentrated loads along either the tangential or the normal direction of the free surface. We supply a semi-analytic solution to those boundary-value problems in the cracked half-plane, and validate the theory by comparing the theoretical results in terms of stress fields, stress intensity factors (SIFs) and crack opening displacement (COD) with those from finite-element simulations. The theoretical approach shows how two edge cracks may shield the stress intensity factors of each other in a quantitative manner. For the typical Kalthoff-Winkler cracks of length a and being spaced by a distance d, their SIFs KI decay with decreasing d, and KI = KI0 − KI1 [1−exp(−a/d)] It converges to KI0—the SIF of a single edge crack when d approaches to infinity. Those observations and the theory approach itself provide a general way to analyze the mechanical consequence of edge cracks in engineering practice.

我们在本文中展示了 Schwarz-Christoffel 映射和 Muskhelishvili 方法与分数函数序列的结合，用于求解开裂半平面的弹性场，并放大了两个典型问题，一个是从边缘一点发出两条射线的双分支裂缝，另一个是间隔一定距离的两条边缘裂缝。我们考虑了典型的加载条件，包括远场均匀拉应力和沿自由表面切线方向或法线方向的集中载荷。我们提供了开裂半平面上这些边界值问题的半解析解，并通过比较应力场、应力强度因子（SIF）和开裂位移（COD）方面的理论结果与有限元模拟结果，验证了该理论。理论方法显示了两个边缘裂缝如何以定量方式屏蔽彼此的应力强度因子。对于长度为 a、间距为 d 的典型 Kalthoff-Winkler 裂纹，其 SIF KI 随 d 的减小而衰减，当 d 接近无穷大时，KI = KI0 - KI1 [1-exp(-a/d)] 收敛到 KI0，即单边裂纹的 SIF。这些观察结果和理论方法本身为分析工程实践中边缘裂缝的力学后果提供了一种通用方法。

Mechanics of Materials

Independent parameters of orthotropic linear transformation-based yield functions

Tomas Manik

doi:10.1016/j.mechmat.2024.104927

基于正交各向异性线性变换的屈服函数的独立参数

In this paper, a wide range of linear transformation-based orthotropic yield functions are reformulated in terms of only independent parameters, as they were originally formulated with too many parameters. This allows to perform a well-posed yield surface calibration. The effect of the hydrostatic part of the transformed stress is discussed for all existing formulations of transformation-based yield functions. The need for a parameter reduction for yield functions with a higher number of parameters is even more significant, as their use is becoming increasingly important for multiscale modelling based on virtual experiments by crystal plasticity. Use of independent parameters is critical for efficient training of neural networks linking crystal and continuum plasticity.

本文将基于线性变换的大范围正交各向异性屈服函数仅用独立参数进行了重新表述，解决了它们原来的表述参数过多的问题。这允许执行一个良好的屈服面校准。对于所有现有的基于转换的屈服函数公式，讨论了转换应力中流体静力部分的影响。对具有更多参数的屈服函数进行参数化简的需求更为重要，因为它们的使用对于基于晶体塑性虚拟实验的多尺度建模变得越来越重要。使用独立参数是有效训练连接晶体和连续介质塑性的神经网络的关键。

International Journal of Plasticity

A gradient-extended thermomechanical model for rate-dependent damage and failure within rubberlike polymeric materials at finite strains

L. Lamm, A. Awad, J.M. Pfeifer, H. Holthusen, S. Felder, S. Reese, T. Brepols

doi:10.1016/j.ijplas.2024.103883

类橡胶聚合物材料在有限应变下速率相关损伤和失效的梯度扩展热力学模型

Rate-dependencies play a crucial role in the mechanical response of polymeric materials. Besides viscoelasticity, many polymers also show pronounced rate-dependent behaviour with respect to damage accumulating within the material. Furthermore, thermal effects and large deformations have to be taken into account when modelling the mechanical behaviour of polymers. Within this work, we propose a novel fully thermomechanically coupled material model for the description of rate-dependent damage combined with viscoelasticity at finite strains. The model is based on the multiplicative decomposition of the deformation gradient into thermal and mechanical parts as well as a further decomposition of the mechanical part into equilibrium and non-equilibrium contributions. To describe the temporal dependencies of the damage evolution, we make use of a Perzyna-type approach. We furthermore show the thermodynamically consistent derivation of stresses and heat sources which arise due to energy dissipations triggered by the inelastic effects within the material. With the given material formulation, we are able to describe both, damage due to creep and due to relaxation in a precise manner. Besides the theoretical aspects, we describe the numerical implementation into finite element software and present numerical studies demonstrating the capabilities of the given model.

速率依赖性在聚合物材料的力学响应中起着至关重要的作用。除了粘弹性外，许多聚合物还表现出明显的速率依赖行为，即材料内部的损伤积累。此外，在模拟聚合物的机械行为时，必须考虑热效应和大变形。在这项工作中，我们提出了一种新的完全热机械耦合材料模型，用于描述有限应变下的速率相关损伤与粘弹性相结合。该模型基于将变形梯度乘分解为热和机械部分，并将机械部分进一步分解为平衡贡献和非平衡贡献。为了描述损伤演化的时间依赖性，我们使用了perzyna型方法。我们进一步展示了由于材料内部非弹性效应引发的能量耗散而产生的应力和热源的热力学一致的推导。根据给定的材料公式，我们能够以精确的方式描述蠕变和松弛造成的损伤。除了理论方面，我们描述了有限元软件的数值实现，并提出了数值研究，证明了给定模型的能力。

Thin-Walled Structures

Design of cellular steel beams subjected to lateral torsional buckling

Nicaolas Boissonnade, Joanna Nseir, Hugues Somja

doi:10.1016/j.tws.2024.111604

侧扭屈曲作用下蜂窝钢梁的设计

The present paper investigates the lateral torsional buckling resistance of cellular steel beams numerically. Such beams are quite sensitive to lateral instability owing to a substantial increase in depth of the cross-section with respect to the base profile. While a companion paper [1] was dedicated to (i) characterising experimentally the behaviour of cellular and Angelina beams and to (ii) validating dedicated non-linear shell F.E. models, this paper details the results of extensive numerical studies. Several key parameters in the structural response are investigated, such as the base cross-section profile, bending moment distribution, size and position of the openings, steel grade and member slenderness. The results have further been used to assess an original design proposal for the lateral torsional buckling resistance of such girders. The improved design rules are shown to provide accurate yet safe ultimate load predictions. Also, in comparison with existing and available design rules, the proposal is seen to allow for substantially higher design loads – still safe-sided –, potentially leading to significant material savings.

本文对多孔钢梁的抗侧扭屈曲性能进行了数值研究。这种梁对横向不稳定性相当敏感，因为相对于基础剖面，截面深度大幅增加。虽然一篇论文[1]致力于(i)实验表征细胞和安吉丽娜光束的行为，以及(ii)验证专用非线性壳层F.E.模型，但本文详细介绍了广泛的数值研究结果。研究了影响结构响应的几个关键参数，如基础截面轮廓、弯矩分布、开口尺寸和位置、钢种和构件长细比。结果进一步用于评估这种梁的横向扭转屈曲抗力的原始设计方案。改进后的设计规则提供了准确而安全的极限荷载预测。此外，与现有和可用的设计规则相比，该建议被认为允许更高的设计负载-仍然是安全的-可能导致大量的材料节省。

Transversely heterogeneous nonlocal Timoshenko beam theory: A reduced-order modeling via distributed-order fractional operators

Wei Ding, Sansit Patnaik, Fabio Semperlotti

doi:10.1016/j.tws.2024.111608

横向异质非局部Timoshenko光束理论:基于分布阶分数算子的降阶建模

Nonlocal effects are widely identified in micro/nano systems and have been studied extensively in recent decades. Nevertheless, existing studies mostly focus on the modeling of homogeneous nonlocal systems and as a result, cannot model micro/nanostructures with heterogeneously distributed nonlocal effects. This study introduces a reduced-order nonlocal Timoshenko beam model that facilitates precise modeling of micro-elastic beams with layer-wise heterogeneous nonlocal effects. First, a fully-resolved two-dimensional (2D) plane-strain fractional-order nonlocal elastic framework is developed to provide reference solutions for 2D nonlocal beam problems. Building upon this general nonlocal elasticity theory, an equivalent one-dimensional (1D) nonlocal Timoshenko model is then developed. The layer-wise heterogeneous nonlocal information is captured by using distributed-order (DO) operators, and the impacts arising from the nonlocal heterogeneity are further characterized by introducing two auxiliary parameters. Both 1D and 2D approaches are applied to simulate the mechanical responses of nonlocal beams. Direct comparisons of numerical simulations produced by either the 1D or the fully-resolved 2D model confirm that the DO Timoshenko beam formulation (together with the two auxiliary parameters) can capture not only the overall beam deflection but also the additional shear effect induced by the heterogeneous nonlocality. Computational cost assessment also indicates the proposed approach’s superior performance. The proposed DO Timoshenko model enables model-order reduction without compromising the heterogeneous nonlocal description of the material hence leading to an efficient and accurate reduced-order nonlocal modeling approach that addresses the limitations of prior nonlocal microstructural theories and extends applicability to a broader range of heterogeneous nano/microstructures.

近几十年来，非局部效应在微纳米系统中得到了广泛的研究。然而，现有的研究大多集中在均匀非局部系统的建模上，无法对非局部效应分布不均的微纳结构进行建模。本文引入了一种降阶非局部Timoshenko梁模型，便于对具有分层非局部非均匀效应的微弹性梁进行精确建模。首先，建立了一个完全解析的二维平面应变分数阶非局部弹性框架，为二维非局部梁问题提供参考解。建立在这个一般的非局部弹性理论，一个等效的一维(1D)非局部Timoshenko模型，然后发展。采用分布式顺序(DO)算子捕获分层异构非局部信息，并引入两个辅助参数进一步表征非局部异构的影响。采用一维和二维两种方法模拟了非局部梁的力学响应。由一维或全分辨二维模型产生的数值模拟的直接比较证实，DO Timoshenko梁公式(连同两个辅助参数)不仅可以捕获整体梁挠度，还可以捕获由非局域性引起的附加剪切效应。计算成本评估也表明了该方法的优越性。提出的DO Timoshenko模型能够在不影响材料异质非局部描述的情况下实现模型阶数的降低，从而导致一种有效和准确的降低阶非局部建模方法，解决了先前非局部微结构理论的局限性，并将适用性扩展到更广泛的异质纳米/微结构。