【新文速递】2024年9月16日固体力学SCI期刊最新文章_ACT_Mechanical_Additive_System_Deform_振动_疲劳_断裂_复合材料_非线性_化学_建筑_增材_焊接_裂纹_参数优化_理论

【新文速递】2024年9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 1 篇International Journal of Solids and StructuresHydride induced embrittlement and fracture of non-hardening metals under hydrogen chemical equilibriumA.G. Variasdoi:10.1016/j.ijsolstr.2024.113073氢化学平衡下非硬化金属的氢化物致脆断裂The stress field in the hydride precipitation zone is examined, under conditions of hydrogen chemical equilibrium and constant temperature, in the case of non-hardening metals, by applying slip-line theory. It is proven that the hydride precipitation zone, in any geometry, is a constant stress area. In this area, the principal stresses are equal to the respective principal stresses, before hydride precipitation, minus the difference of hydrostatic stress before and after hydride precipitation. The general relations are applied to the case of a stationary sharp mode-I plane-strain crack and the deviations from Prandtl-field are derived, in the [-π/4, +π/4] sector ahead of the tip, where hydrides precipitate. In this case, the hydride precipitation sector is characterized by a constant hydride volume fraction. In addition, hydride precipitation is associated with the development of elastic sectors along the crack faces and the reduction of the centered fan sectors; the relation between hydride precipitation zone stress trace and the extent of the centered fan sector is presented. The mode-I plane-strain blunted crack is also considered and the deviations from the logarithmic spiral slip-lines is discussed together with the reduction of hydride volume fraction as the blunted crack-tip is approached. A general fracture criterion, based on the strength of hydride platelets, is derived, which indicates that fracture occurs, when a critical hydride precipitation zone stress trace dominates. The criterion is applied, under the condition of a dominant K-field annulus, surrounding the plastic zone, and the estimated threshold stress intensity factor of delayed hydride cracking correlates favorably with experimental measurements.应用滑移线理论，研究了非硬化金属在氢化学平衡和恒温条件下的氢化物析出区应力场。证明了在任何几何形状下，氢化物析出区都是一个恒应力区。在这一区域，主应力等于氢化物析出前各自的主应力，减去氢化物析出前后的静水应力差。将一般关系式应用于固定尖锐i型平面应变裂纹的情况，并推导出在尖端前面的[-π/4， +π/4]扇区中氢化物析出的普朗特场偏差。在这种情况下，氢化物沉淀区以恒定的氢化物体积分数为特征。此外，氢化物的析出与沿裂纹面弹性扇区的发育和中心扇区的减小有关;给出了氢化物沉淀区应力迹与中心扇区范围的关系。本文还考虑了i型平面应变钝化裂纹，讨论了与对数螺旋滑移线的偏差以及接近钝化裂纹尖端时氢化物体积分数的减小。基于氢化物薄片的强度，导出了一般断裂准则，表明当临界氢化物析出区应力迹占主导地位时发生断裂。该准则应用于塑性区周围的主导k场环空条件下，估计的延迟氢化物开裂的阈值应力强度因子与实验测量结果具有良好的相关性。Journal of the Mechanics and Physics of SolidsEvolution of static to dynamic mechanical behavior in topological nonreciprocal active metamaterialsZehuan Tang, Tingfeng Ma, Hui Chen, Yuanwen Gaodoi:10.1016/j.jmps.2024.105865拓扑非互易活性超材料静态力学行为向动态力学行为的演化Based on the Maxwell-Betti theorem, static non-reciprocity has been realized by using nonlinearity, but this non-reciprocity has strict restrictions on input amplitude and structure size (number of units). Here, we propose an active metamaterial with two polarizational components (translation and rotation), which uses active control to add external forces on the units to break reciprocity at the level of the interactions between the units. We show analytically and simulatively that breaking reciprocity at the level of the interactions directly leads to a huge asymmetric response of displacement in a static system, this displacement-specific characteristic not only has no restrictions on size, input amplitude, and suitable geometric asymmetry, but also can be transmitted to rotation by coupling under large deformation. After the evolution from statics to dynamics, asymmetric transmission and unidirectional amplification of vector solitons are both implemented in this system. Our research uncovers the evolution of static non-reciprocity to dynamic non-reciprocity while building a bridge between non-reciprocity physics and soliton science.基于Maxwell-Betti定理，利用非线性实现了静态非互易性，但这种非互易性对输入幅度和结构大小(单元数)有严格的限制。在这里，我们提出了一种具有两个极化分量(平移和旋转)的活性超材料，它使用主动控制在单元上添加外力以打破单元之间相互作用水平上的互易性。分析和模拟表明，在相互作用水平上破坏互易性直接导致静态系统中巨大的位移不对称响应，这种位移特定特性不仅对大小、输入幅值和适当的几何不对称没有限制，而且可以在大变形下通过耦合传递给旋转。该系统实现了矢量孤子的非对称传输和单向放大。我们的研究揭示了从静态非互易到动态非互易的演化过程，在非互易物理学和孤子科学之间架起了一座桥梁。Mechanics of MaterialsHomogenization of quasi-periodic conformal architectured materials and applications to chiral latticesS.E. Alavi, K. Cheikho, C. Laurent, J.F. Ganghofferdoi:10.1016/j.mechmat.2024.105146准周期共形结构材料的均匀化及其在手性晶格中的应用In this study, we propose to extend asymptotic periodic homogenization for non-periodic continuous microstructured media, assuming that the non-periodic geometry (called quasi-periodic) can be designed by a conformal planar transformation of a periodic parent domain architectured media with periodically disposed unit cells. Conformal transformations are shown to play a privileged role in the design of circular macroscopic heterogeneous domains tessellated with non-periodic unit cells, obtained from a periodic parent domain architectured with these unit cells. The conditions for conformal invariance are established, leading to the general form of conformal transformation in their dependencies upon the periodic coordinates. It is shown that any conformal map can be decomposed into the product of an isotropic dilatation function of the first periodic spatial position of decreasing exponential type and a rotation characterized by an angular function linear in the second periodic position. A general theory of quasi-periodic homogenization in the framework of conformal transformations is established for the first time, leading to an expression of the tensor of quasi-periodic moduli which are fully evaluated from the solution of the elasticity boundary value problem posed over the periodic unit cell. The influence of microcurvature distortion of individual unit cells on their effective properties is evaluated. Closed-form solutions are confronted to numerical examples issued from the implementation of circular periodicity in a finite element solver, in order to showing overall a good agreement with the identified homogenized moduli.在本研究中，我们提出扩展非周期连续微结构介质的渐近周期均匀化，假设非周期几何(称为准周期)可以通过具有周期性配置的单元胞的周期母域结构介质的共形平面变换来设计。共形变换在非周期单元胞镶嵌的圆形宏观异质畴的设计中发挥了特殊的作用，这些非周期单元胞是由这些单元胞构成的周期母域得到的。建立了保形不变性的条件，得到了它们随周期坐标变化的保形变换的一般形式。结果表明，任何共形映射都可以分解为第一个周期空间位置的指数递减型各向同性膨胀函数与第二个周期位置的角函数线性特征的旋转的乘积。首次建立了保形变换框架下拟周期均匀化的一般理论，得到了拟周期模张量的表达式，该表达式完全由周期单元胞弹性边值问题的解求得。分析了单晶胞微曲率畸变对其有效性能的影响。在有限元求解器中对循环周期的实现给出了数值算例，并与所识别的均质模总体上吻合较好。International Journal of PlasticityAchieving superior strength-ductility balance by tailoring dislocation density and shearable GP zone of extruded Al-Cu-Li alloyXuanxi Xu, Guohua Wu, Xin Tong, Liang Zhang, Cunlong Wang, Fangzhou Qi, Xiaopeng Zeng, Youjie Guodoi:10.1016/j.ijplas.2024.104135 通过调整挤压铝铜锂合金的位错密度和可剪切GP区，实现了优异的强度-塑性平衡Pre-stretching is commonly employed to accelerate ageing precipitation kinetics in wrought Al-Cu-Li alloys, but uneven precipitation resulting from dislocation pile-ups often degrades ductility. Herein, the strength and ductility of extruded Al-Cu-Li alloy are significantly improved through a novel thermomechanical treatment, involving pre-ageing and pre-stretching, followed by low-temperature interrupted ageing. A superior balance between high yield strength (∼ 657 MPa) and good ductility (elongation to fracture of ∼ 13.5%) is obtained, with elongation increased by 105% compared to the conventional T8 temper, while maintaining a respectable yield strength. Microstructure analysis reveals that dense Guinier–Preston (GP) zones induced by pre-ageing effectively dissipate energy from dislocation sliding, resulting in a uniform dislocation configuration even at 8% pre-stretching. However, the GP zone density is greatly reduced due to their dissolution following pre-stretching. Upon interrupted ageing, the reprecipitation of GP zones forms a homogeneous mixture of δ′, GP zones, and T1 phases. This combination alleviates local stress concentrations and lengthens the dislocation mean free path during tensile testing by shearing the GP zones at multiple sites, thereby improving ductility. Simultaneously, T1 precipitates strengthen the alloy by pinning dislocations and promoting dislocation cross-slip, improving work hardening capacity. The dissolution of GP zones also redistributes the Cu atoms within the matrix, further enhancing the intrinsic ductility of the Al matrix. These findings offer valuable insights for developing high-performance wrought Al-Cu-Li alloys.预拉伸通常用于加速变形铝铜锂合金的时效析出动力学，但位错堆积导致的不均匀析出通常会降低塑性。通过预时效、预拉伸和低温中断时效等新型热处理，挤压铝铜锂合金的强度和塑性得到了显著提高。在高屈服强度(~ 657 MPa)和良好延展性(断裂伸长率~ 13.5%)之间取得了良好的平衡，与传统T8回火相比，伸长率提高了105%，同时保持了可观的屈服强度。微观结构分析表明，预时效引起的密集的ginier - preston (GP)带有效地耗散了位错滑动产生的能量，即使在8%的预拉伸下也能形成均匀的位错结构。然而，由于预拉伸后的溶解，GP带密度大大降低。中断时效后，GP区再析出形成δ′、GP区和T1相的均匀混合物。这种组合缓解了局部应力集中，并通过剪切多个位置的GP区延长了拉伸试验中的位错平均自由路径，从而提高了延性。同时，T1析出物通过钉住位错和促进位错交叉滑移来强化合金，提高加工硬化能力。GP带的溶解也使Cu原子在基体中重新分布，进一步增强了Al基体的固有延展性。这些发现为开发高性能锻造Al-Cu-Li合金提供了有价值的见解。Thin-Walled StructuresInfluence of feed entrance angle on transverse tearing burr formation in the milling of superalloy honeycomb with ice filling constraintShaowei Jiang, Haibo Liu, Yueshuai Zuo, Daomian Sun, Jianming Li, Kuo Liu, Yongqing Wang, Steven Y. Liangdoi:10.1016/j.tws.2024.112472进给角对充冰约束下高温合金蜂窝铣削横向撕裂毛刺形成的影响In the end milling of superalloy honeycomb cores, the contact form between the cutting tool and honeycomb wall and the force state of the honeycomb wall are variable, there will be difficulties in chip removal. The irregular extension of transverse tearing burrs can deteriorate the machining quality of honeycomb core surfaces, thereby adversely affecting the assembly and service performance of sandwich structures. Based on kinematic analysis, modeling of the removal and deflection process of honeycomb walls was conducted. The feed entrance angle in the case of machining thin walls with high feed speeds was characterized, and the force state of the honeycomb wall and the degree of shear or compression it bears were analyzed. Analytical models of damage scale and single-tooth cutting state were established under different feed entrance angles. The impact of feed entrance angle on the minimum burr length and the minimum constraint failure width was analyzed. The milling experiments of GH4099 superalloy honeycomb wall with ice filling constraint were designed and conducted to clarify the influence of different feed entrance angles on cutting force and transverse tearing burr length. The morphology of burrs and the wear form of the cutting tool were analyzed, and the formation mechanism of transverse tearing burr on the honeycomb sidewalls was revealed. The research results indicate that the feed force Fx is 2.1 to 4.7 times greater than the main force Fy or the back force Fz. When the feed entrance angle is less than 90°, transverse tearing burrs either do not occur, or occur crimped burrs that are gradually removed. Particularly within the range of 0° to 30°, the machining quality is better. The cutting force has a significant shearing effect on the honeycomb wall, making it susceptible to plastic deformation and reaching the fracture strain. The cutting edge can effectively remove material from the honeycomb wall, resulting in normal wear on the minor flank face and tip of the cutting tool. When the feed entrance angle is greater than 90°, it is easy to form large banded burrs, and the burr length is relatively similar to about 1500μm. The cutting force has a significant extrusion effect on the honeycomb wall, resulting in minimal deflection deformation of the honeycomb wall, and making it difficult to fracture. The cutting tool fails to perform effective cutting, leading to increased friction between the cutting tool and honeycomb wall, which continuously induces irregular extension of the burrs. The research findings are of great significance for achieving damage control in metal honeycomb core machining and guiding process and clamping optimization.在对超合金蜂窝芯进行端铣加工时，刀具与蜂窝壁的接触形式以及蜂窝壁的受力状态都是多变的，因此会出现排屑困难的情况。横向撕裂毛刺的不规则延伸会恶化蜂窝芯表面的加工质量，从而对夹层结构的装配和使用性能产生不利影响。基于运动学分析，对蜂窝壁的清除和变形过程进行了建模。分析了以高进给速度加工薄壁时的进给入口角，并分析了蜂窝壁的受力状态及其承受的剪切或压缩程度。建立了不同进给入口角下损伤规模和单齿切削状态的分析模型。分析了进给入口角对最小毛刺长度和最小约束失效宽度的影响。设计并进行了带有冰填充约束的 GH4099 超合金蜂窝壁铣削实验，以明确不同进给入口角对切削力和横向撕裂毛刺长度的影响。分析了毛刺的形态和切削刀具的磨损形式，揭示了蜂窝侧壁横向撕裂毛刺的形成机理。研究结果表明，进给力 Fx 是主力 Fy 或反向力 Fz 的 2.1 至 4.7 倍。当进料入口角小于 90° 时，横向撕裂毛刺要么不会出现，要么会出现卷曲毛刺并逐渐被去除。特别是在 0° 至 30° 范围内，加工质量更好。切削力对蜂窝壁有明显的剪切作用，使其容易产生塑性变形，达到断裂应变。切削刃能有效去除蜂窝壁上的材料，导致切削刀具的小翼面和刀尖出现正常磨损。当进给入口角大于 90° 时，容易形成较大的带状毛刺，毛刺长度相对较近，约为 1500μm。切削力对蜂窝壁的挤压作用明显，导致蜂窝壁的挠曲变形极小，不易断裂。切削工具无法进行有效切削，导致切削工具与蜂窝壁之间的摩擦力增大，从而不断诱发毛刺的不规则延伸。该研究成果对于实现金属蜂窝芯加工中的损伤控制以及指导工艺和装夹优化具有重要意义。来源：复合材料力学仿真Composites FEM