【新文速递】2024年4月21日复合材料SCI期刊最新文章

今日更新：International Journal of Solids and Structures 4 篇，Thin-Walled Structures 1 篇International Journal of Solids and StructuresA thermo-mechanical, viscoelasto-plastic model for semi-crystalline polymers exhibiting one-way and two-way shape memory effects under phase changeHasan Gülaşik, Maxime Houbben, Clara Pereira Sànchez, Juan Manuel Calleja Vázquez, Philippe Vanderbemden, Christine Jérôme, Ludovic Noelsdoi:10.1016/j.ijsolstr.2024.112814半结晶聚合物在相变下单向和双向形状记忆效应的热机械粘弹塑性模型A finite strain phenomenological model is developed to simulate the shape memory behavior of semi-crystalline polymers under thermo-mechanical loading. The polymer is considered to be a composite of crystalline and amorphous phases with constant volume fractions. While the amorphous phase is stable, the crystalline phase is considered to change phase with temperature. Therefore, the crystalline phase is considered further to be composed of two phases, whose volume fractions are controlled by a temperature and strain dependent function: the melted phase which is soft, and the crystallized phase which is stiff.A pressure dependent viscoelasto-plastic behavior is considered for the constitutive model of the different phases. In addition to pressure dependent plasticity, additional deformation measures are applied to the crystalline phase to model temporary (imperfect shape fixity) and permanent (imperfect shape recovery) deformations in a thermo-mechanical loading cycle. Formulating a compressible plastic flow during the phase changes yields the possibility to capture both one-way and two-way shape memory effects. As a consequence, the load-dependent and anisotropic thermal expansion observed experimentally in semi-crystalline polymers during phase change is naturally captured.The model is validated within a test campaign performed on nano-composite having a semi-crystalline polymer as a base material. It is shown that the model gives close results with the tests and it is able to capture the shape fixity and shape recovery behaviors of the polymer, for both one-way and two-way shape memory effects.建立了一种有限应变唯象模型来模拟半结晶聚合物在热机械载荷下的形状记忆行为。聚合物被认为是具有恒定体积分数的结晶相和非晶相的复合物。非晶相是稳定的，而晶相则随温度变化而变化。因此，进一步认为结晶相由两相组成，其体积分数由温度和应变相关函数控制:熔融相是软相，结晶相是硬相。考虑了不同相本构模型的压力相关粘弹塑性行为。除了压力相关的塑性外，还将额外的变形措施应用于结晶相，以模拟热-机械加载循环中的临时(不完全形状固定性)和永久(不完全形状恢复)变形。在相变过程中形成可压缩塑性流，可以捕获单向和双向形状记忆效应。因此，在实验中观察到的载荷依赖和各向异性热膨胀在半结晶聚合物的相变过程中被自然捕获。该模型在以半结晶聚合物为基材的纳米复合材料上进行了测试。结果表明，该模型与实验结果接近，能够捕捉聚合物的形状固定性和形状恢复行为，具有单向和双向形状记忆效应。Modelling ductile damage in metals and alloys through Weyl condition exploiting local gauge symmetriesSanjeev Kumardoi:10.1016/j.ijsolstr.2024.112820利用局部规范对称性，利用Weyl条件模拟金属和合金的延性损伤Local translational and scaling symmetries in space–time is exploited for modelling ductile damage in metals and alloys over wide ranges of strain rate and temperature. The invariant energy density corresponding to the ductile deformation is constructed through the gauge invariant curvature tensor by imposing the Weyl like condition. In contrast, the energetics of the plastic deformation is brought in through the gauge compensating field emerged due to local translation and attempted to explore the geometric interpretation of certain internal variables often used in classical viscoplasticity models. Invariance of the energy density under the local action of translation and scaling is preserved through minimally replaced space–time gauge covariant operators. Minimal replacement introduces two non-trivial gauge compensating fields pertaining to local translation and scaling. These are used to describe ductile damage, including plastic flow and micro-crack evolution in the material. A space–time pseudo-Riemannian metric is used to lay out the kinematics in a finite-deformation setting. Recognizing the available insights in classical theories of viscoplasticity, we also establish a correspondence of the gauge compensating field due to spatial translation with Kröner’s multiplicative decomposition of the deformation gradient. Thermodynamically consistent coupling between viscoplasticity and ductile damage is ensured through an appropriate degradation function. Non-ordinary state-based (NOSB) peridynamics (PD) discretization of the model is used for numerical implementation. We conduct simulations of uniaxial deformation to validate the model against available experimental evidence and to assess its predictive features. The model’s viability is tested in reproducing a few experimentally known facts, viz., strain rate locking in the stress–strain response, whose origin is traced to a nonlinear microscopic inertia term arising out of the space–time translation symmetry. Finally, we solved 2D and axisymmetric deformation problems for qualitatively validating the model’s viability. NOSB peridynamics axisymmetric formulation in finite deformation setup is also presented.时空中的局部平移和尺度对称性被用于模拟金属和合金在大应变率和温度范围内的延性损伤。通过施加Weyl样条件，通过规范不变曲率张量构造出与韧性变形相对应的不变能量密度。相比之下，塑性变形的能量学是通过局部平移产生的规范补偿场引入的，并试图探索经典粘塑性模型中常用的某些内部变量的几何解释。通过最小替换的空时规范协变算子保持了能量密度在局部平移和标度作用下的不变性。最小替换引入了两个与局部平移和缩放相关的非平凡规范补偿域。这些被用来描述延性损伤，包括材料中的塑性流动和微裂纹演化。利用时空伪黎曼度量来表示有限变形情况下的运动学。认识到经典粘塑性理论中可用的见解，我们还建立了由于空间平移引起的规范补偿场与Kröner变形梯度的乘法分解的对应关系。通过适当的退化函数确保粘塑性和延性损伤之间的热力学一致性耦合。采用基于非常状态(NOSB)的模型周动力学离散化方法进行数值实现。我们进行单轴变形的模拟，以验证模型对现有的实验证据，并评估其预测特征。该模型的可行性是通过再现一些实验已知的事实来检验的，即应变率锁定在应力-应变响应中，其起源可以追溯到由时空平移对称产生的非线性微观惯性项。最后，我们解决了二维和轴对称变形问题，定性验证了模型的可行性。给出了有限变形条件下NOSB周动力轴对称公式。A novel bi-material tubular metamaterial with twist effects under thermal and uniaxial loadsBeicheng Lin, Fucong Lu, Weijia Li, Chuanbiao Zhang, Yilin Zhudoi:10.1016/j.ijsolstr.2024.112821热载荷和单轴载荷下具有扭转效应的新型双材料管状超材料In this work, a novel bi-material missing rib-type tetra-chiral tubular metamaterial (BMTTM) is designed by utilizing the base materials with different coefficients of thermal expansion (CTEs), and considering various material combinations. Counterintuitively, twist effect can be observed with temperature variation or uniaxial load for the BMTTM. The theoretical formations of the twist angle, Poisson's ratio (PR) and CTE are established and verified subsequently by numerical simulations. Theoretical and numerical results indicate that tailoring twist angle of the BMTTM can be achieved by manipulating the base material combination and the microstructural geometry. The BMTTM proffers a novel avenue to design temperature sensors, actuators, and satellite support tubes, serving in fluctuating temperature environments.本文利用不同热膨胀系数的基材，考虑不同的材料组合，设计了一种新型双材料缺失肋型四手性管状超材料(BMTTM)。与直觉相反，在温度变化或单轴载荷下，BMTTM可以观察到扭转效应。建立了扭角、泊松比(PR)和CTE的理论表达式，并通过数值模拟对其进行了验证。理论和数值计算结果表明，通过调整基材组合和微观组织几何形状，可以实现BMTTM的定制扭转角。BMTTM为设计温度传感器、执行器和卫星支撑管提供了一种新途径，可用于波动温度环境。Simulating shot peening based on a dislocation density-based model with a novel time integration algorithmFeiHu Ren, MingHao Zhao, Chunsheng Lu, JianWei Zhang, BingBing Wangdoi:10.1016/j.ijsolstr.2024.112823基于位错密度模型和一种新的时间积分算法模拟喷丸强化Shot peening has been widely used in processing various components since it can bring in residual compressive stress and effectively refine the grain size of impacted area. To simulate grain refinement induced by shot peening, the dislocation density-based model has recently been introduced, however, the existing time integration algorithm is not stable and usually leads to divergent solutions in iterations. In this paper, a novel time integration algorithm is proposed for the dislocation density-based model. Based upon the algorithm, numerical studies on multi-shot AISI4340 steel are carried out with different coverages, velocities, shot diameters, and peening angles. It is shown that the method converges faster than the two-level iteration method, and the predicted dislocation cell structure sizes after shooting are consistent with experimental results. Besides that, increasing coverage can refine the size of a dislocation cell, which is closely dependent on the shot diameter, impact velocity, and angle. Thus, to achieve the desired grain size or the depth of refinement, it is necessary to take the shot diameter and velocity into account simultaneously.喷丸强化可以产生残余压应力，有效地细化冲击区的晶粒尺寸，因此广泛应用于各种零件的加工中。为了模拟喷丸强化引起的晶粒细化，近年来提出了基于位错密度的时间积分模型，但现有的时间积分算法不稳定，迭代求解往往出现发散。针对基于位错密度的模型，提出了一种新的时间积分算法。在此基础上，对AISI4340钢在不同覆盖面积、速度、丸径和喷丸角度下的多丸体进行了数值研究。结果表明，该方法收敛速度快于两级迭代法，预测的射击后位错胞结构尺寸与实验结果一致。此外，增加覆盖范围可以细化位错单元的尺寸，而位错单元的尺寸与弹丸直径、冲击速度和角度密切相关。因此，为了达到理想的晶粒尺寸或细化深度，有必要同时考虑丸径和速度。Thin-Walled StructuresPerspectives on the generalized modeling of six beam theories: A unified dynamic stiffness matrixHao Zhou, Mingxiang Ling, Yihui Yindoi:10.1016/j.tws.2024.111863六梁理论广义建模展望:统一动力刚度矩阵High-precision, efficient and streamlined methods for the dynamic modeling and analyzing of engineering structures have consistently captured attention of designers and researchers. This paper addressed this increasing demand by presenting a generalized modeling and analyzing method. Specially, a unified model was proposed to integrate six beam theories into a single formula. Upon this model, a unified dynamic stiffness matrix was derived, serving as an elemental building block for formulating the transfer matrix, frequency-dependent mass and stiffness matrices as well as further integrating finite element method, dynamic stiffness matrix method and transfer matrix method. Through this transition, challenges associated with transcendental eigenvalue in dynamic stiffness matrix method and transfer matrix method was effectively resolved and the advantages of transfer matrix method in handling complex structure were maximized. Given the widespread utilization of curved beams in buildings, bridges, robotics and sensors, the proposed method was validated through comparative analysis with other methods, focusing on both curved and straight beams. Furthermore, this study delineated applicability scopes of different beam theories and provided the strategic approach for curved and straight beams. The feasibility of this strategy was demonstrated through an investigation involving a corrugated structure comprising both straight and curved beams.高精度、高效率、流线型的工程结构动力学建模和分析方法一直受到设计人员和研究人员的关注。针对这一日益增长的需求，本文提出了一种通用的建模和分析方法。特别地，提出了一个统一的模型，将六种梁理论整合到一个公式中。在此基础上，推导出统一的动力刚度矩阵，作为构建传递矩阵、频率相关质量矩阵和刚度矩阵的基本构件，并进一步将有限元法、动力刚度矩阵法和传递矩阵法进行整合。通过这种转变，有效地解决了动刚度矩阵法和传递矩阵法中超越特征值的难题，最大限度地发挥了传递矩阵法处理复杂结构的优势。鉴于曲线梁在建筑、桥梁、机器人和传感器中的广泛应用，通过与其他方法的对比分析，验证了所提出的方法，重点是曲线梁和直线梁。进一步界定了不同梁理论的适用范围，为弯梁和直梁的研究提供了策略思路。通过一项包括直梁和弯梁的波纹结构的研究，证明了这种策略的可行性。来源：复合材料力学仿真Composites FEM