【新文速递】2024年7月29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 2 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 3 篇International Journal of Solids and StructuresAtomic simulations of crack propagation in Ni-Al binary single crystal superalloy with a central crackLiu Yang, Huicong Dong, Dayong Wu, Haikun Ma, Zhihao Feng, Peng He, Balaji Narayanaswamy, Baocai You, Qian Wang, Ru Sudoi:10.1016/j.ijsolstr.2024.113006含中心裂纹Ni-Al二元单晶高温合金裂纹扩展的原子模拟Nickel (Ni)-based single-crystal superalloys are of great importance in the aircraft industry due to their excellent mechanical properties, and cracks as unavoidable defects may affect the mechanical performances of materials dramatically. In this paper, large scale molecular dynamics (MD) simulations are carried out to understand the deformation mechanisms of Ni-based single crystal with a central crack under tension. Here, the effects of matrixes (γ, γ′ and γ/γ′), strain rates (1 × 109 s−1 ∼ 3 × 109 s−1) and temperatures (300 K∼900 K) on the role of crack propagation are considered. It is observed that dislocations and slip systems in the γ′ model are concentrated near the crack, resulting in the rapid expansion of dislocation, which leads to the fastest crack growth speed and early fracture. While the crack propagation rate of γ and γ/γ′ models are relatively slow, due to the combined action of the Lomer-Cottrell lock and stacking fault tetrahedron structure and Stair-rod dislocation, which hinders crack propagation. In addition, deformation at increased strain rates and/or reduced temperatures, lead to superior yield stress and Young′s modulus for models with a central crack at γ/γ′ interface. On the other hand, high temperature and high strain rate will promote crack propagation in the γ phase, and the higher the strain rate and/or temperature, the faster the crack propagation speed will be. These results will enrich our understanding on the crack propagation and evolution mechanisms in Ni-based single crystal superalloy.镍基单晶高温合金具有优异的力学性能，在航空工业中具有重要的应用价值，而裂纹作为不可避免的缺陷会对材料的力学性能产生极大的影响。本文采用大尺度分子动力学(MD)模拟方法研究了含中心裂纹的镍基单晶在拉伸作用下的变形机理。本文考虑了基体(γ、γ′和γ/γ′)、应变速率(1 × 109 s−1 ~ 3 × 109 s−1)和温度(300 K ~ 900 K)对裂纹扩展的影响。观察到γ′模型中位错和滑移体系集中在裂纹附近，导致位错迅速扩展，从而导致裂纹扩展速度最快，早期断裂。而γ和γ/γ′模型的裂纹扩展速度相对较慢，这是由于lomo - cottrell锁和层错四面体结构以及阶梯位错的共同作用，阻碍了裂纹扩展。此外，在增加应变速率和/或降低温度下的变形，导致在γ/γ′界面处具有中心裂纹的模型具有优越的屈服应力和杨氏模量。另一方面，高温和高应变速率会促进γ相裂纹扩展，应变速率和/或温度越高，裂纹扩展速度越快。这些结果将丰富我们对镍基单晶高温合金裂纹扩展和演化机制的认识。Journal of the Mechanics and Physics of SolidsReconstruction of the local contractility of the cardiac muscle from deficient apparent kinematicsG. Pozzi, D. Ambrosi, S. Pezzutodoi:10.1016/j.jmps.2024.105793从表观运动学缺陷重建心肌局部收缩力Active solids are a large class of materials, including both living soft tissues and artificial matter, that share the ability to undergo strain even in absence of external loads. While in engineered materials the actuation is typically designed a priori, in natural materials it is an unknown of the problem. In such a framework, the identification of inactive regions in active materials is of particular interest. An example of paramount relevance is cardiac mechanics and the assessment of regions of the cardiac muscle with impaired contractility. The impossibility to measure the local active forces directly suggests us to develop a novel methodology exploiting kinematic data from clinical images by a variational approach to reconstruct the local contractility of the cardiac muscle. By finding the stationary points of a suitable cost functional we recover the contractility map of the muscle. Numerical experiments, including severe conditions with added noise to model uncertainties, and data knowledge limited to the boundary, demonstrate the effectiveness of our approach. Unlike other methods, we provide a spatially continuous recovery of the contractility map without compromising the computational efficiency.活性固体是一大类材料，包括活体软组织和人造物质，即使在没有外部载荷的情况下，它们也具有承受应变的能力。在工程材料中，驱动通常是先验设计的，而在天然材料中，这是一个未知的问题。在这样一个框架中，活性物质中非活性区域的识别是特别有趣的。最重要的一个相关的例子是心脏力学和心肌收缩性受损区域的评估。直接测量局部活动力的不可能性提示我们开发一种新的方法，通过变分方法从临床图像中利用运动学数据来重建局部心肌收缩力。通过寻找一个合适的代价函数的平稳点，我们恢复了肌肉的收缩图。数值实验，包括对模型不确定性添加噪声的严峻条件，以及仅限于边界的数据知识，证明了我们的方法的有效性。与其他方法不同的是，我们在不影响计算效率的情况下提供了收缩性图的空间连续恢复。Unravelling the relation between free volume gradient and shear band deflection induced extra plasticity in metallic glassesHaiming Lu, Zhenghao Zhang, Yao Tang, Haofei Zhoudoi:10.1016/j.jmps.2024.105806揭示了金属玻璃中自由体积梯度与剪切带挠度之间的关系Previous experiments have revealed that the controllable introduction of structural gradients in metallic glasses (MGs) can endow the materials with extra plasticity due to the gradient-induced deflection of shear bands. However, the relation between the spatial structural gradient and the initiation of shear band deflection remains unclear. The current study has been focused on investigating the relationship between the improved mechanical properties of MGs and structural gradients specified by the distribution of the intrinsic free volume. Molecular dynamics (MD) simulations are firstly performed on homogeneous MG models containing various initial free volume values, showing that the shear band angle increases with decreasing free volume under uniaxial compression, whereas higher shear band angle is observed under uniaxial tension with increasing free volume. Based on the asymmetric behaviors of MGs under compression and tension, a theoretical model is developed to quantitatively characterize the influence of free volume on the mechanical response of MGs, which incorporates a failure criterion based on free volume generation during external loadings. The model can be further utilized to interpret and predict the fracture strain, shear band angle, maximum stress, and fracture surface morphology of gradient structured MGs in both simulations and experiments. The relationship between free volume gradient and shear band deflection induced extra plasticity established in this study provides valuable guidance for the structural design of MGs with enhanced mechanical properties.先前的实验表明，在金属玻璃中可控地引入结构梯度可以使材料由于剪切带的梯度引起的挠曲而具有额外的塑性。然而，空间结构梯度与剪切带挠曲发生的关系尚不清楚。目前的研究主要集中在研究mggs力学性能的改善与由内禀自由体积分布所决定的结构梯度之间的关系。首先对具有不同初始自由体积值的均质MG模型进行了分子动力学模拟，结果表明，在单轴压缩条件下，剪切带角随自由体积的减小而增大，而在单轴拉伸条件下，剪切带角随自由体积的增大而增大。基于弹性材料在压缩和拉伸作用下的不对称行为，建立了一个定量表征自由体积对弹性材料力学响应影响的理论模型，该模型包含了一个基于外载荷下自由体积产生的破坏准则。该模型可进一步用于模拟和实验中梯度构造mggs的断裂应变、剪切带角、最大应力和断口形貌的解释和预测。本研究建立的自由体积梯度与剪切带挠曲引起的额外塑性之间的关系，对具有增强力学性能的镁合金结构设计具有重要的指导意义。International Journal of PlasticityAchieving excellent uniform tensile ductility and strength in dislocation-cell-structured high-entropy alloysRui Huang, Lingkun Zhang, Abdukadir Amar, Peter K. Liaw, Tongmin Wang, Tingju Li, Yiping Ludoi:10.1016/j.ijplas.2024.104079 在位错细胞结构高熵合金中实现了优异的均匀拉伸延展性和强度Body-centered-cubic (BCC) high-entropy alloys (HEAs) encounter significant challenges in obtaining a high uniform tensile ductility (UTD). A dense dislocation-cell (DC) structure is produced in a heterogeneously grained HEA under tensile deformation, resulting from the anchored dislocation motion by grain interior elemental segregation. This fluctuation in elemental concentration is facilitated by thermomechanical processing. The activation of multiple-slip mechanisms, prompted by strain incompatibility among grains of varying sizes, significantly propels this process forward. This novel DC structure simultaneously increased the UTD (by 349.1%) and yield strength (σ0.2, by 29.0%) for a stable BCC HEA. Specifically, the single-phase alloy achieved a record-high UTD of 7.5% and an σ0.2 of > 1,200 MPa, outperforming the counterparts of all the single-phase BCC HEAs. We employed a combination of transmission electron microscopy, in-situ scanning electron microscopy tensile testing coupled with an electron backscatter diffraction technology to investigate underlying strengthening mechanisms and identified that the serious stress concentration as a result of prevalent planar slip caused premature failure and localized strain of common BCC HEAs. At the initial stage of deformation, the DC structure promoted the activation of multiple slip systems and facilitated the extension of a plastic flow across the sample volume, effectively weakening stress concentration and premature failure. The extended plasticity zone and intensified dislocation interactions contributed to the increased UTD and σ0.2. These findings offer valuable inspiration for tailoring alloy properties via microstructure strategies and promoting their adoption in advanced manufacturing.体心立方（BCC）高熵合金（HEAs）在获得高均匀拉伸延展性（UTD）方面遇到了重大挑战。在拉伸变形条件下，异质晶粒 HEA 中会产生密集的位错胞（DC）结构，这是晶粒内部元素偏析导致的锚定位错运动造成的。热机械加工促进了元素浓度的波动。不同尺寸晶粒之间的应变不相容性导致的多重滑移机制的启动，极大地推动了这一过程。这种新型直流结构同时提高了稳定 BCC HEA 的UTD（349.1%）和屈服强度（σ0.2，29.0%）。具体而言，单相合金的UTD达到了创纪录的7.5%，σ0.2大于1,200兆帕，优于所有单相BCC HEA。我们采用透射电子显微镜、原位扫描电子显微镜拉伸测试和电子反向散射衍射技术相结合的方法来研究其潜在的强化机制，发现由于普遍存在的平面滑移导致严重的应力集中，从而造成普通 BCC HEA 的过早失效和局部应变。在变形的初始阶段，直流结构促进了多重滑移系统的激活，促进了塑性流动在样品体积上的扩展，有效削弱了应力集中和过早失效。塑性区的扩展和位错相互作用的加强导致了UTD和σ0.2的增加。这些发现为通过微结构策略定制合金特性以及促进其在先进制造业中的应用提供了宝贵的启示。Thin-Walled StructuresFree Vibration analysis of C/SiC blisk based on modified global mode methodQian Xu, Lei Hou, Lixian Hou, Zhonggang Li, Shuangxing Ren, Mohamed K. Aboudaif, Emad Mahrous Awwad, Nasser A. Saeeddoi:10.1016/j.tws.2024.112285基于改进全局模态法的C/SiC圆盘自由振动分析The bladed disk is the core component which is under load in aero-engine, rocket engine and gas turbine. In recent years, the bladed disk has developed towards the direction of integrated bladed disk (blisk) and being applied with ceramic matrix composites. However, there is no accurate semi-analytical dynamic model to describe the dynamic characteristic of ceramic matrix composite blisk. In this paper, a new semi-analytical method, modified global mode method (MGMM) is proposed to model the 2D C/SiC laminated blisk. In proposed method, Chebyshev polynomials series are used to expand the displacements of the blades and disk, constraints between blades and disk is strictly satisfied by multi-modal transformation and integrated into governing equation, and high-order shear deformation theory is combined to establish the dynamic model of the blisk of 2D C/SiC laminated composite material. The proposed method avoids the matrix singular problem appearing in traditional global mode method when modeling of combined structure and makes the system perform dynamic analysis and mode prediction without mode extraction and reconstruction. Then, amplitude frequency response and modal experiment are carried out to verify the correctness and convergence of the proposed method. Finally, under the framework of proposed method, the effects of material parameters and geometric parameters on the modal characteristics of the blisk are analyzed. The results show that compared with the geometric parameters, the material parameters have less influence on the modal characteristics of blisk, additionally, a series of modal steering is observed. The work in this paper can provide theoretical guidance for the dynamic design of composite blisk.叶片盘是航空发动机、火箭发动机和燃气轮机中承受载荷的核心部件。近年来，叶片向整体式叶片方向发展，并与陶瓷基复合材料结合使用。然而，目前还没有准确的半解析动力学模型来描述陶瓷基复合材料叶片的动态特性。本文提出了一种新的半解析方法——修正全局模态法(MGMM)来模拟二维碳化硅/碳化硅薄片。该方法采用切比雪夫多项式级数展开叶片和圆盘的位移，通过多模态变换严格满足叶片和圆盘之间的约束，并将其集成到控制方程中，结合高阶剪切变形理论建立了二维C/SiC层合复合材料叶片的动力学模型。该方法避免了传统全局模态法在组合结构建模时出现的矩阵奇异问题，使系统无需模态提取和重构即可进行动态分析和模态预测。然后通过幅频响应和模态实验验证了所提方法的正确性和收敛性。最后，在该方法的框架下，分析了材料参数和几何参数对飞盘模态特性的影响。结果表明，与几何参数相比，材料参数对叶片模态特性的影响较小，并观察到一系列模态转向。本文的工作可以为复合叶片的动态设计提供理论指导。Advanced lightweight composite shells: Manufacturing, mechanical characterizations and applicationsYing Gao, Zhibin Li, Xingyu Wei, Yuntong Du, Zhengong Zhou, Jian Xiongdoi:10.1016/j.tws.2024.112286先进轻质复合材料壳体:制造、机械特性及应用The development of modern aeronautical and aerospace industries has greatly been accelerated by the upgradation of advanced lightweight architecture materials. As a recognized and promising kind, lightweight composite structures amalgamate the benefits of advanced fiber-reinforced composite materials and innovative design concepts for weight reduction and thus have attracted substantial attention from structural engineers and scholars over the past few decades. The primary objective of the present article is to provide an extensive review and analysis of the recent achievement of a pivotal component in modern aeronautical and aerospace architectures: lightweight composite shells. This review delves into various composite grid, grid-stiffened, and sandwich shells with diverse constructions, elucidating their structural design concepts and applicable conditions. The academic discourse focuses on the three relevant key component technologies for developing lightweight composite shells, including manufacturing techniques, mechanical characterization and optimum design methods. Additionally, this article presents a comprehensive review of their applications and potentials in aeronautical and aerospace systems. The existing research gap and contemplates on future directions are discussed. The encountered challenges and possible opportunities for lightweight composite shells are also illuminated.先进轻量化建筑材料的升级换代，极大地促进了现代航空航天工业的发展。轻量化复合材料结构作为一种公认的、有发展前景的结构形式，融合了先进纤维增强复合材料的优点和创新的减重设计理念，在过去的几十年里引起了结构工程师和学者的广泛关注。本文的主要目的是对现代航空和航天建筑中的关键部件:轻质复合材料外壳的最新成就进行广泛的回顾和分析。本文对各种结构形式的复合网架、加筋网架和夹层网架进行了深入研究，阐明了它们的结构设计理念和适用条件。本文主要讨论了复合材料轻量化壳体的制造技术、力学性能表征和优化设计方法。此外，本文还对其在航空航天系统中的应用和潜力进行了综述。讨论了现有的研究差距和对未来发展方向的思考。轻质复合材料外壳面临的挑战和可能的机遇也被阐明。Compressive properties of aperiodic but ordered cellular materials inspired by Penrose tilingsGe Qi, Ji-jing Tian, Chen-xi Liu, Yun-long Chen, Song Jiang, Zhi-jie He, Meng Han, Kai-Uwe Schröder, Li Madoi:10.1016/j.tws.2024.112287受彭罗斯瓷砖启发的非周期性有序细胞材料的压缩特性Various cellular materials have been emerging in the past decades, whose design strategy focuses on the periodic arrangements of a representative unit cell. Recent studies indicate that aperiodic tessellations possess the ability to eliminate the risk of catastrophic global failure. However, extracting the exact relation between each localized microstructural features and macroscopic material properties of stochastic structures is not applicable due to the intrinsic randomness and disorderliness. In an effort to break through this challenge, this paper develops a class of aperiodic but ordered cellular materials (AOCMs) inspired by three types of Penrose tilings. Both finite element simulations and quasi-static compressive experiments are carried out to address the macroscopic mechanical performance and the microscopic mechanisms. The results show that the distinct deformation and failure mechanisms are induced by their different topological configurations, including the architectural shapes and tessellating orientations. The proposed AOCMs possess excellent potentials as load carrying structures and energy absorbers, and the outcomes reported here serve to provide a new perspective on the development of advanced cellular materials.在过去的几十年里，出现了各种各样的细胞材料，其设计策略集中在具有代表性的单元细胞的周期性排列上。最近的研究表明，非周期镶嵌具有消除灾难性全局失效风险的能力。然而，由于随机结构本身的随机性和无序性，无法准确提取其各个局部微观结构特征与宏观材料特性之间的关系。为了突破这一挑战，本文开发了一类非周期性但有序的细胞材料(aocm)，灵感来自三种类型的彭罗斯瓷砖。采用有限元模拟和准静态压缩实验两种方法研究了复合材料的宏观力学性能和微观力学机制。结果表明:不同的拓扑结构(包括结构形状和镶嵌方向)导致了不同的变形破坏机制;所提出的aocm具有作为承载结构和能量吸收材料的良好潜力，本文报道的结果为先进细胞材料的发展提供了新的视角。来源：复合材料力学仿真Composites FEM