【新文速递】2024年5月31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 3 篇，Thin-Walled Structures 2 篇

International Journal of Solids and Structures

Discrete element model for the anisotropic cracking of shrinking material layers

Roland Szatmári, Zoltán Halász, Akio Nakahara, So Kitsunezaki, Ferenc Kun

doi:10.1016/j.ijsolstr.2024.112890

收缩材料层各向异性开裂的离散元模型

Mechanical perturbation of thin layers of pastes on a substrate results in anisotropic cracking during desiccation which allows for a controlled generation of crack patterns with a high relevance for industrial applications. In the present paper we propose a modelling framework to capture the anisotropy induced by initial perturbations which imprint directional dependent material features into the layer. Our approach is based on a random tessellation of the layer using convex polygons which are made anisotropic by elongating or compressing them along the direction of perturbation. Physical properties of the particles’ cohesive contacts are determined by the geometrical characteristics of polygons giving rise to a well controlled anisotropy in the mechanical response of the material and in the structure of the fracture pattern emerging during shrinking. The main advantage of the approach is that both the structural disorder of the layer and the strength of anisotropy are controlled by a single parameter. Based on computer simulations we demonstrate that varying its two parameters the model reproduces the qualitative features of experimental findings and provides advantages over existing modelling approaches.

在干燥过程中，基材上薄层糊状物的机械扰动导致各向异性开裂，这使得裂缝模式的控制产生与工业应用高度相关。在本文中，我们提出了一个建模框架，以捕获由初始扰动引起的各向异性，这些扰动将方向相关的材料特征印入层中。我们的方法是基于使用凸多边形的层的随机镶嵌，这些凸多边形通过沿着扰动方向拉长或压缩它们而成为各向异性。颗粒内聚接触的物理性质是由多边形的几何特征决定的，这些几何特征在材料的力学响应和收缩过程中出现的断裂模式结构中产生了良好的控制各向异性。该方法的主要优点是层的结构无序性和各向异性强度都由一个参数控制。基于计算机模拟，我们证明了改变其两个参数的模型再现了实验结果的定性特征，并提供了优于现有建模方法的优点。

Journal of the Mechanics and Physics of Solids

A variational phase-field framework for multiphysics modelling of degradation and stress corrosion cracking in biodegradable magnesium alloys

Dawei Zhang, Songyun Ma, Julia Nachtsheim, Shunqi Zhang, Bernd Markert

doi:10.1016/j.jmps.2024.105694

可生物降解镁合金降解和应力腐蚀开裂多物理场模型的变分相场框架

Biodegradable magnesium alloys have been developed as promising biomedical materials for temporary implants. To facilitate the development of implant design, it is essential to understand and quantify the corrosion behaviour of magnesium alloys under mixed chemo-mechanical loadings. In this study, a multiphase-field model is proposed based on the variational principle to capture the interactions between corrosion and ductile fracture in biodegradable magnesium alloys. Multiple order parameters are introduced to track the interfaces associated with crack propagation and magnesium dissolution. The deformation-fracture-corrosion interactions are considered in the energetic variational formulation with coupling functions. The governing equations are discretised using an incremental variational method and solved by a staggered scheme. Parametric studies on the coupling functions are performed to demonstrate the flexibility of the model. The proposed multiphase-field model is calibrated and validated by in vitro experiments with tensile specimens of rare-earth magnesium alloy WE43MEO. The experimental and computational results demonstrate that the proposed model can capture the degradation and stress corrosion cracking behaviours in the immersion tests and slow strain rate tensile-corrosion tests.

可生物降解镁合金是一种很有前途的生物医学临时植入材料。为了促进植入物设计的发展，有必要了解和量化镁合金在混合化学-机械载荷下的腐蚀行为。本文基于变分原理，建立了可降解镁合金腐蚀与韧性断裂相互作用的多相场模型。引入多阶参数来跟踪与裂纹扩展和镁溶解有关的界面。在带耦合函数的能量变分公式中考虑了变形-断裂-腐蚀的相互作用。控制方程采用增量变分法离散，并采用交错格式求解。对耦合函数进行了参数化研究，以证明模型的灵活性。通过WE43MEO稀土镁合金拉伸试样的体外实验，对所建立的多相场模型进行了标定和验证。实验和计算结果表明，该模型能较好地反映浸没试验和慢应变速率拉伸腐蚀试验中的退化和应力腐蚀开裂行为。

A kinetic theory for the mechanics and remodeling of transient anisotropic networks

Franck J. Vernerey, Behnam Rezaei, Samuel Lamont

doi:10.1016/j.jmps.2024.105713

瞬态各向异性网络力学和重塑的动力学理论

We present a statistically-based theoretical framework to describe the mechanical response of dynamically crosslinked semi-flexible polymer networks undergoing finite deformation. The theory starts from a statistical description, via a distribution function, of the chain conformation and orientation. Assuming a so-called tangent affine deformation of the chains, this distribution is then allowed to evolve in time due to a combination of elastic network distortion and a permanent chain reconfiguration enabled by dynamic crosslinks. After presenting the evolution law for the chain distribution function, we reduce the theory to the evolution of the network conformation tensor in both its natural and current state. With this model, we use classical thermodynamics to determine how the stored elastic energy, energy dissipation, and true stress evolve in terms of the network conformation. We show that the model degenerates to classical anisotropic hyperelastic models when crosslinks are permanent, while we recover the classical form of the transient network theory (that describes hyper-viscoelasticity) when chains are fully flexible. Theoretical predictions are then illustrated and compared to the literature for both basic model problems and biomechanically relevant situations.

我们提出了一个基于统计的理论框架来描述动态交联半柔性聚合物网络在有限变形下的力学响应。该理论从链的构象和取向的分布函数的统计描述出发。假设所谓的链的正切仿射变形，这种分布随后被允许随着时间的推移而演变，这是由于弹性网络扭曲和动态交联所实现的永久链重构的结合。在给出了链分布函数的演化规律后，将其简化为网络构象张量在自然状态和当前状态下的演化。利用该模型，我们利用经典热力学来确定存储的弹性能、能量耗散和真实应力如何随网络构象的变化而变化。我们表明，当交联是永久的时，模型退化为经典的各向异性超弹性模型，而当链是完全柔性时，我们恢复了瞬态网络理论(描述超粘弹性)的经典形式。然后对理论预测进行说明，并与基本模型问题和生物力学相关情况的文献进行比较。

New Insights in the 3-D Rheological Properties and Collagen Fibers Orientation in Murine Periodontal Ligaments

Mahmoud Sedky Adly, Richard Younes, Marta Martin, Thierry Cloitre, Afnan Sedky Adly, Ivan Panayotov, Philippe Bousquet, Csilla Gergely, Frederic J.G. Cuisinier, Delphine Carayon, Elias Estephan

doi:10.1016/j.jmps.2024.105715

小鼠牙周韧带三维流变特性和胶原纤维取向的新认识

The rheological properties of the periodontal ligament are key parameters to understand the homeostatic stability of the tooth supporting apparatus. The objective of this study is to lay new insights on the rheological properties and structural information of different regions in murine periodontal ligament by using atomic force (AFM) and multi-photon microscopy (MPM). A significant variation in elasticity of different regions was measured. The elasticity of periodontal ligament showed a significant tendency to become softer towards the furcation, the nearest area to the center of resistance of the tooth. This can open a new prospective for connecting the rheological adaptation of periodontal ligament to the tooth geometry that defines the center of resistance. Another important finding revealed by the second harmonic generation (SHG) signal exhibited by collagen fibers and measured by MPM is that the orientation of fibers in the furcation region can both provide space for tooth vertical movement with high compressive loads and prevent horizontal tooth movement. Additionally, it was found that the dispersion of the angles at different levels of cutting indicates homogeneity in the directionality of fibers across different regions. These results provide an accurate description of the rheological properties and structural information of periodontal ligament, which can serve as a base for comparison with other local and systemic diseases that may influence the periodontal ligament.

牙周膜的流变特性是了解牙齿支撑装置稳态稳定性的关键参数。本研究的目的是利用原子力(AFM)和多光子显微镜(MPM)对小鼠牙周膜不同区域的流变特性和结构信息有新的认识。测量了不同区域弹性的显著差异。牙周韧带的弹性有明显的趋向于向分叉处软化，分叉处是离牙齿阻力中心最近的地方。这为将牙周韧带的流变适应与确定阻力中心的牙齿几何形状联系起来开辟了新的前景。胶原纤维显示的二次谐波(SHG)信号和MPM测量的另一个重要发现是，纤维在分叉区域的方向既可以为高压缩载荷下牙齿的垂直运动提供空间，又可以阻止牙齿的水平运动。此外，我们还发现，在不同切割水平上，角度的分散表明纤维在不同区域的方向性是均匀的。这些结果提供了对牙周韧带流变特性和结构信息的准确描述，可作为与其他可能影响牙周韧带的局部和全身性疾病进行比较的基础。

Thin-Walled Structures

Post-fire mechanical properties of titanium-clad bimetallic steel after cold-forming process: Experiment and Constitutive model

Yu Shi, Jie Wang, Xuhong Zhou, Xuanyi Xue

doi:10.1016/j.tws.2024.112057

钛包双金属钢冷成形后火后力学性能:实验与本构模型

Titanium-clad bimetallic steel (TCBS), composed of a titanium alloy cladding layer and carbon steel substrate layer, has been proposed to mitigate the effects of corrosion and enhance the durability of steel structures. This study conducted tensile coupon test to explore the coupling effect of the cold-forming process and fire exposure on the monotonic mechanical properties of TCBS. Following the cold-forming process and fire exposure, there was no visible cracking observed in either the cladding or the metallurgical bonding layer. Test results revealed a notable enhancement in the strength properties and a decrease in the ductility of the TCBS specimens after cold forming. Moreover, the study elucidated the effects of the exposure temperature and cooling method on the stress–strain curves and fractures of TCBS corner specimens. Three different fracture sequences of the TCBS corner specimens were observed during monotonic tensile test. The key mechanical parameters were concerned in this study, which included the yield and ultimate strengths, yield and ultimate strains, elastic modulus, elongation after fracture, and section shrinkage. Then, the variation trends of key mechanical parameters were clarified. Predictive equations were developed for these parameters of the TCBS corner specimens after fire exposure. Additionally, two constitutive models were developed for the corner TCBS stress–strain curves with and without the yield plateau, enabling their use in numerical and theoretical investigations of the post-fire performance of cold-formed TCBS components.

钛包层双金属钢(TCBS)是一种由钛合金包层和碳钢衬底层组成的材料，可以减轻钢结构的腐蚀影响，提高钢结构的耐久性。本研究通过拉伸联片试验，探讨冷成型工艺与火暴露对TCBS单调力学性能的耦合效应。经过冷成形和火处理后，熔覆层和冶金结合层均未出现明显的裂纹。试验结果表明，冷成形后TCBS试样的强度性能显著提高，而塑性明显降低。此外，研究还阐明了暴露温度和冷却方式对TCBS角部试样应力-应变曲线和断裂的影响。在单调拉伸试验中，观察到三种不同的TCBS角部试样断裂顺序。研究的关键力学参数包括屈服和极限强度、屈服和极限应变、弹性模量、断裂伸长率和断面收缩率。然后，明确了关键力学参数的变化趋势。建立了TCBS角部试样在火灾作用后这些参数的预测方程。此外，针对存在和不存在屈服平台的拐角TCBS应力-应变曲线，建立了两种本构模型，使其能够用于冷弯TCBS构件火灾后性能的数值和理论研究。

Inextensional vibrations of thin spherical shells using strain gradient elasticity theory

Rajesh K Yadav, Shakti S Gupta

doi:10.1016/j.tws.2024.112061

用应变梯度弹性理论研究薄球壳的非伸展振动

We study inextensional vibrations of the spherical shell using strain gradient elasticity theory under Kirchhoff-Love hypotheses. For admissibility of the inextensional deformations the shell is punctured by making a tiny hole. The shell is assumed to be made of linearly elastic, homogeneous, and isotropic material. The closed form expression for the frequencies of inextensional modes of vibration of spherical caps of various polar angles and that of nearly complete spherical shell are derived using Rayleigh's method. Towards this, the displacement and velocity fields are obtained by setting the membrane strains to zero. Further, to facilitate the existence of inextensional vibrations, boundaries are assumed to be traction free. The frequencies are computed for the positive and negative signs in the strain gradient term of the constitutive law. The computed frequencies, employing negative sign are found to be higher than those computed using classical elasticity theory. The opposite effect is seen when the frequencies are computed with the positive sign. Further, the frequencies are found to saturate when the positive sign is used in the constitutive law. Parametric studies viz. variation in frequencies with the circumferential wavenumbers for different values of length scale parameter, variation in frequencies with circumferential wavenumbers for different values of polar angles and a given length scale parameter, variation of frequency with increasing polar angle for a given circumferential wavenumber, variation of saturation wavenumber with increasing polar angle, and increasing length scale parameter are carried out. The frequencies of nearly a spherical shell with increasing circumferential wavenumber are also computed.

本文利用Kirchhoff-Love假设下的应变梯度弹性理论研究了球壳的非外延振动。为了允许非拉伸变形，壳体被打一个小洞刺穿。假定壳体是由线弹性、均匀和各向同性的材料制成的。用瑞利法导出了不同极角球帽和近完整球壳的非伸展振型频率的封闭表达式。为此，将膜应变设为零，得到位移场和速度场。此外，为了便于存在非外延振动，边界被假定为无牵引力。计算了本构律应变梯度项的正负符号的频率。用负号计算得到的频率比用经典弹性理论计算得到的频率高。当频率以正号计算时，可以看到相反的效果。此外，当本构律中使用正号时，发现频率饱和。参数化研究包括:不同长度尺度参数值下频率随周向波数的变化、不同极角值下频率随周向波数的变化、给定长度尺度参数下频率随极角的变化、给定周向波数下频率随极角的变化、饱和波数随极角的变化以及长度尺度参数的增加。并计算了随周波数增加的近球壳的频率。