【新文速递】2025年1月10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，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇
International Journal of Solids and Structures
A minimization theory in finite elasticity to prevent self-intersection
Adair R. Aguiar, Lucas A. Rocha
doi:10.1016/j.ijsolstr.2024.113198
有限弹性中防止自交的最小化理论
The theory of classical linear elasticity predicts self-intersection in the neighborhood of interior points of anisotropic solids, crack tips, and corners. This physically unrealistic behavior is characterized by the violation of the local injectivity condition, according to which, the determinant of the deformation gradient, J ≜ det F, must be positive. One way to impose this condition in elasticity consists of minimizing the total potential energy subjected to the condition J≥ɛ>0, where ɛ is a small positive parameter. We present a minimization theory constrained by J≥ɛ>0 for hyperelastic solids undergoing finite deformations and derive necessary conditions for a deformation field to be a minimizer, which include both continuity of traction and dissipation-free conditions across a surface of discontinuity. We then apply this theory in the analysis of equilibrium of an annular disk made of an orthotropic St Venant-Kirchhoff material. This material is a natural constitutive extension of its classical linear counterpart. The disk is fixed on its inner surface and compressed by a constant pressure on its outer surface. The disk problem is formulated as both a boundary value problem (disk BVP) and a minimization problem (disk MP), which are solved in the context of both the classical and the constrained (J≥ɛ) nonlinear theories. These formulations yield non-smooth solutions for large enough pressure, which pose numerical difficulties. To address these difficulties, we use a phase-plane technique to construct a trajectory of solution for the disk BVP and the finite element method together with nonlinear programming tools to find a minimizer for the disk MP. In the classical nonlinear theory, we find that there is a critical pressure p-, which tends to zero as the inner radius of the disk tends to zero, above which a solution of either the disk BVP or the disk MP becomes non-smooth and predicts J≤ 0. In addition, p- is smaller than its counterpart predicted by the classical linear theory and, therefore, serves as an upper bound below which the linear theory is valid. In the constrained nonlinear theory, the solutions of both the disk BVP and the disk MP agree very well and satisfy all the necessary conditions for an admissible minimizer, including the injectivity condition. Analytical and numerical results show that, for an annular disk, the Lagrange multiplier field associated with the imposition of the local injectivity constraint remains bounded as ɛ tends to zero. This behavior is different from the one reported in the literature for the disk problem formulated in the context of a constrained linear theory. In this case, the Lagrange multiplier becomes unbounded as ɛ tends to zero.
经典线性弹性理论预测，在各向异性固体内部点、裂纹尖端和角点附近会出现自相交现象。这种不符合物理实际的行为表现为局部单射条件的违反，即变形梯度的行列式 J ≜ det F 必须为正。在弹性学中施加这一条件的一种方法是，在 J≥ɛ>0 的条件下最小化总势能，其中 ɛ 是一个小的正参数。我们提出了一个受 J≥ɛ>0 约束的超弹性固体有限变形的最小化理论，并推导出变形场成为极小值的必要条件，其中包括在不连续面两侧的牵引力连续性和无耗散条件。然后，我们将该理论应用于由正交各向异性圣维南 - 基尔霍夫材料制成的环形盘的平衡分析。这种材料是其经典线性对应物的自然本构扩展。该盘的内表面固定，外表面受到恒定压力的压缩。圆盘问题被表述为一个边值问题（圆盘边值问题）和一个极小化问题（圆盘极小化问题），这两个问题在经典理论和受约束（J≥ɛ）的非线性理论的背景下得到解决。这些表述在压力足够大的情况下会产生非光滑解，这给数值计算带来了困难。为了解决这些困难，我们使用相平面技术来构建圆盘边值问题的解轨迹，并结合有限元方法和非线性规划工具来寻找圆盘极小化问题的极小值。在经典非线性理论中，我们发现存在一个临界压力 p-，它随着圆盘内半径的减小而趋于零，当压力超过 p- 时，圆盘边值问题或圆盘极小化问题的解会变得不光滑，并预测 J≤ 0。此外，p- 小于经典线性理论所预测的对应值，因此它可作为线性理论有效的上限。在受约束的非线性理论中，圆盘边值问题和圆盘极小化问题的解非常吻合，并满足所有可接受极小值的必要条件，包括单射条件。分析和数值结果表明，对于环形圆盘，与局部单值性约束施加相关的拉格朗日乘子场在 ɛ 趋于零时保持有界。这种行为与文献中报道的在约束线性理论背景下提出的圆盘问题的情况不同。在这种情况下，拉格朗日乘子在 ɛ 趋于零时变得无 界。
Journal of the Mechanics and Physics of Solids
A modified semi-soft model of liquid crystal elastomers: application to elastic and viscoelastic responses
Yu Zhou, Chen Wei, Lihua Jin
doi:10.1016/j.jmps.2025.106027
液晶弹性体的修正半软模型：在弹性和粘弹性响应中的应用
Liquid crystal elastomers (LCEs) are emerging actuating materials composed of polymer networks and liquid crystal mesogens. A plateau in the stress-strain curve of LCEs, typical of the semi-soft characteristics, is commonly observed. Although the classical semi-soft model based on compositional fluctuations intends to capture this feature, it does not accurately predict the stress plateau. Moreover, the extended viscoelastic models often lack quantitative comparisons between their theoretical predictions and experimental results. To address these limitations, we phenomenologically modify the semi-soft model, applying it to capture both of the elastic and viscoelastic responses of LCEs. The modified model is further implemented into finite element simulations and used to study intriguing inhomogeneous deformation of LCEs. We demonstrated robust predictions of our model by quantitatively comparing with experimental results.
液晶弹性体（LCEs）是由聚合物网络和液晶介质组成的新兴致动材料。在LCEs的应力应变曲线上，通常观察到一个平台，典型的半软特征。尽管基于成分波动的经典半软模型试图捕捉这一特征，但它不能准确地预测应力平台。此外，扩展粘弹性模型往往缺乏理论预测和实验结果之间的定量比较。为了解决这些限制，我们从现象学上修改了半软模型，将其应用于捕获lce的弹性和粘弹性响应。将修正后的模型进一步应用于有限元模拟，并用于研究lce的非均匀变形。通过与实验结果的定量比较，我们证明了模型的稳健性。
Gradient-enhanced ductile fracture constitutive modeling in implicit two-scale finite element analysis
Tianwen Tan, Ikumu Watanabe
doi:10.1016/j.jmps.2025.106025
隐式双尺度有限元分析中梯度增强韧性断裂本构建模
In the field of damage modeling for ductile materials, numerous models have successfully addressed various fracture responses, as well as the need for robust algorithms and solutions to computational challenges. This study developed a damage model based on continuum damage mechanics. It addresses mesh regularization, a primary computational issue in macroscopic structural fracture analysis through a gradient-enhanced damage model using micromorphic theory and incorporating damage hardening variables. To provide a physical explanation for the characteristic lengths associated with the gradient-enhanced term, an extended “two-scale” computational homogenization approach was employed to define the length scale between the macro- and microscale. This microvariable within a micromorphic extension can be utilized to model the damage hardening mechanism, which cannot be fully captured via high-resolution localized characterization. In duplex microstructures, the length scale can be defined by the microstructure size relative to the width of the micro–shear band. This explains the damage overlapping phenomenon between the two-scales.
在延性材料损伤建模领域，许多模型已经成功地解决了各种断裂响应，以及对鲁棒算法和解决计算挑战的需求。本文建立了基于连续损伤力学的损伤模型。它通过使用微形态理论和结合损伤硬化变量的梯度增强损伤模型来解决网格正则化问题，这是宏观结构断裂分析中的一个主要计算问题。为了提供与梯度增强项相关的特征长度的物理解释，采用扩展的“双尺度”计算均匀化方法来定义宏观和微观尺度之间的长度尺度。这种微形态扩展中的微变量可以用来模拟损伤硬化机制，而这种机制无法通过高分辨率的局部表征完全捕获。在双相组织中，长度尺度可以由微观组织尺寸与微剪切带宽度的关系来定义。这就解释了两个尺度之间的损伤重叠现象。
Topology generation and quantitative stiffness analysis for fiber networks based on disordered spatial truss
Shaoxiong Huang, Yafeng Wang, Xian Xu, Yaozhi Luo
doi:10.1016/j.jmps.2025.106030
基于无序空间桁架的光纤网络拓扑生成及定量刚度分析
Fiber networks are essential functional materials, yet existing mechanical models only capture specific aspects of their mechanical properties. This paper proposes a general mechanical model for fiber networks based on pin-jointed bar assemblies. The topology and stress modes of the networks are generated through topology optimization. The model decouples and quantifies the contributions of entropy fluctuation, rearrangement, and fiber stress to the overall stiffness, explaining stiffness variations in actin networks and the differences in stiffness between thermal and athermal networks. It also replicates the experimental strengthening effects of prestressed fiber networks, theoretically justifying the power-law relationship between applied stress/strain and stiffness. A macroscopic 3D-printed experiment validates the model's ability to replicate stiffness variations and the rearrangement phenomena observed in collagen networks under compression and shear. This model enables a comprehensive investigation of the mechanical properties of fiber networks and contributes to the design of novel biomimetic metamaterials.
光纤网络是必不可少的功能材料，但现有的力学模型只能捕获其机械性能的特定方面。本文提出了一种基于针接杆组件的光纤网络通用力学模型。通过拓扑优化生成网络的拓扑模式和应力模式。该模型解耦并量化了熵波动、重排和纤维应力对整体刚度的贡献，解释了肌动蛋白网络中的刚度变化以及热网络和非热网络之间刚度的差异。它还复 制了预应力纤维网络的实验强化效果，理论上证明了应用应力/应变与刚度之间的幂律关系。宏观3d打印实验验证了该模型在压缩和剪切下复 制胶原蛋白网络中观察到的刚度变化和重排现象的能力。该模型能够全面研究纤维网络的力学性能，并有助于设计新型仿生超材料。
Mechanics of Materials
Exploring mechanical damage in fascia: Experiments and advanced constitutive modeling approaches
Alejandro Aparici-Gil, Marta M. Pérez, Estefanía Peña
doi:10.1016/j.mechmat.2025.105239
探索筋膜的机械损伤：实验和先进的本构建模方法
Biological tissues exhibit complex structures that necessitate mechanical models incorporating details of their key components and the physical processes occurring within the material. Our objective is to enhance the understanding of damage mechanisms in fibered tissues through mechanical testing. This includes conducting uniaxial tensile tests on fascia beyond physiological stretch limits and developing two constitutive models to describe damage and rupture. These models integrate both phenomenological and microstructural perspectives. Two perpendicular directions, corresponding to the two families of collagen fibers, were compared: the longitudinal direction, characterized by greater stiffness, and the transverse direction. The mean Cauchy rupture stress (σr) was reported as 16.67 for the longitudinal direction and 4.76 MPa for the transverse direction, with a significant difference observed between them (p-value <0.05). Similarly, a significant difference in stored strain energy was found between the two directions (p-value<0.05) between directions, being in longitudinal equal to 1.33 N⋅mm/mm3 and 0.49 in transversal one. However, rupture stretches (λr) did not exhibit a significant difference (p-value > 0.05) with values of 1.17 and 1.22 for the longitudinal and transverse directions, respectively. In this study, a hyperelastic constitutive model for fascia was modified to incorporate damage effects into the strain energy function. Additionally, an extended version of a microstructural damage model was developed to effectively replicate the experimental data. The proposed damage models successfully captured the stress–strain behavior and accurately represented the damage process. The coefficient of determination R2 for the fitted data ranged from 0.616 to 0.973, except for Sample IV, which exhibited an R2 value of 0.251 when using the phenomenological model. In all cases, the microstructural model provided a more accurate fit compared to the phenomenological model, with R2 values ranging from 0.748 to 0.927.
生物组织具有复杂的结构，这需要机械模型纳入其关键成分的细节以及材料内部发生的物理过程。我们的目标是通过机械测试来增强对纤维组织损伤机制的理解。这包括对筋膜进行超出生理拉伸极限的单轴拉伸试验，并开发两个本构模型来描述损伤和断裂。这些模型结合了现象学和微观结构的观点。比较了两个相互垂直的方向，分别对应于胶原纤维的两个家族：纵向方向，其刚度更大；以及横向方向。纵向方向的平均柯西断裂应力（σr）报告为 16.67 MPa，横向方向为 4.76 MPa，两者之间存在显著差异（p 值 < 0.05）。同样，在两个方向之间也发现了储存应变能的显著差异（p 值 < 0.05），纵向方向为 1.33 N·mm/mm³，横向方向为 0.49。然而，纵向和横向的破裂伸长率（λr）并未表现出显著差异（p 值＞0.05），其值分别为 1.17 和 1.22。 在本研究中，对筋膜的超弹性本构模型进行了修改，将损伤效应纳入应变能函数。此外，还开发了一种扩展的微观结构损伤模型，以有效地模拟实验数据。所提出的损伤模型成功地捕捉到了应力 - 应变行为，并准确地描述了损伤过程。拟合数据的决定系数 R2 范围为 0.616 至 0.973，但样本 IV 使用经验模型时 R2 值为 0.251。在所有情况下，微观结构模型的拟合精度均高于经验模型，其 R2 值范围为 0.748 至 0.927。
International Journal of Plasticity
Simultaneously enhancing strength and plasticity via direct ageing in additive manufactured Al–Ni–Sc–Zr alloys
Guandong Luo, Han Chen, Lei Hu, Chen Yang, Shuwei Zong, Yanchi Chen, Qing Lian, Hongze Wang, Zhe Chen, Yi Wu, Haowei Wang
doi:10.1016/j.ijplas.2025.104243
同时通过直接时效添加剂制造的Al-Ni-Sc-Zr合金提高强度和塑性
Eutectic Al alloys processed by laser powder bed fusion (LPBF) frequently display metastable cellular structures. The cells are susceptible to decomposition into nanoparticles during ageing. Furthermore, supersaturated solutes can result in additional precipitation during the ageing process. The complicated microstructure evolution observed in LPBF eutectic Al alloys necessitates a comprehensive investigation into their ageing behaviour, to identify the optimal strength and plasticity. Consequently, this study presents a systematic examination of the impact of direct ageing on microstructure evolution in an LPBF Al‒Ni‒Sc‒Zr alloy, analysing associated changes in strength and plasticity. The optimal ageing parameters for strength and plasticity are determined. The results demonstrate that the reduction in strength resulting from cell decomposition can be offset by the strengthening provided by nanoparticles formed due to cell wall spheroidisation and additional supersaturated solute precipitation, achieving excellent yield strength. Furthermore, the transformation of cells into nanoparticles significantly enhances the plasticity by increasing non-uniform strain, which is not well explained by the conventional work hardening theory. A detailed investigation suggests that direct ageing can alleviate dislocation pile-up and strain localisation around cell walls, and reduce the tendency for crack propagation along melt pool boundaries, resulting in a significant increase in non-uniform strain and ultimately, excellent tensile plasticity. This study demonstrates that direct ageing is an effective strategy for simultaneously enhancing the strength and plasticity of LPBF Al–Ni based alloys. The proposed plasticity mechanism offers a new insight into the plastic deformation behaviour of LPBF eutectic Al alloys.
激光粉末床熔接（LPBF）加工的共晶铝合金经常出现亚稳细胞结构。这些细胞在老化过程中很容易分解成纳米颗粒。此外，过饱和溶质在老化过程中会导致额外的沉淀。在LPBF共晶铝合金中观察到复杂的组织演变，需要对其时效行为进行全面的研究，以确定最佳的强度和塑性。因此，本研究系统地研究了直接时效对LPBF Al-Ni-Sc-Zr合金微观组织演变的影响，分析了强度和塑性的相关变化。确定了最优的强度和塑性老化参数。结果表明，由于细胞壁球化和额外的过饱和溶质沉淀形成的纳米颗粒所提供的强化可以抵消细胞分解导致的强度降低，从而获得优异的屈服强度。此外，细胞向纳米颗粒的转化通过增加非均匀应变而显著提高了塑性，这是传统加工硬化理论无法很好解释的。一项详细的研究表明，直接时效可以缓解胞壁周围的位错堆积和应变局部化，并减少沿熔池边界的裂纹扩展趋势，从而显著增加非均匀应变，最终获得优异的拉伸塑性。研究表明，直接时效是同时提高LPBF Al-Ni基合金强度和塑性的有效策略。提出的塑性机理为研究LPBF共晶铝合金的塑性变形行为提供了新的思路。
