【新文速递】2024年12月21日复合材料SCI期刊最新文章_ACT_Mechanical_Additive_Optical_System_疲劳_断裂_复合材料_化学_拓扑优化_光学_航空_航天_增材_裂纹_理论_材料

【新文速递】2024年12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，International Journal of Plasticity 3 篇International Journal of Solids and StructuresInvestigation of unidirectional vibration isolation and nonreciprocal design of axial elastic waves based on topological pumping theoryZixun Lu, Hui Chern, Lingyun Yaodoi:10.1016/j.ijsolstr.2024.113192基于拓扑抽运理论的轴向弹性波单向隔振与非倒易设计研究In this work, a spiral structure (SS) based on the nonreciprocal waveguide theory of adiabatic evolution principle is designed, which can generate dynamic boundaries on a rotation shaft. The spatiotemporal topological pumping formed by SS can achieve nonreciprocal transmission of elastic waves in shaft, and the transmission can achieve unidirectional isolation of shaft vibration. Firstly, transfer matrix method (TMM) is used to theoretically derive the continuity at two-phase spiral periodic shaft structure (SPSS) medium. Then, finite element method (FEM) is utilized to calculate energy bands and frequency response functions of SPSS. Next, the calculations results obtained by FEM are used to analyze the influence of material parameters, geometric dimensions and other factors on band gap, and SPSS of rotation is used to confirm the variation of topological edge modes produced by spatiotemporal pumping. Finally, realistic shaft model and analytical parameters are combined to determine the dimensional parameters and materials of unidirectional vibration isolation shaft, vibration transmission characteristics of spiral shaft are obtained by numerical simulation, and its unidirectional vibration isolation performance is verified through experiment. The results show that SS can achieve spatiotemporal topological pumping function at a certain modulation speed, whenthe band gap is deflected in a specific frequency range, elastic waves can be transmitted unidirectional in deflected frequency range, the dynamic spiral shaft has a good unidirectional vibration isolation effect when the shaft is modulated in the reverse direction, and changing helical angular velocity can tune frequency range of nonreciprocal transmission of elastic waves. The design can provide a theoretical basis for engineering application of unidirectional vibration isolation bushing in wide frequency range.本文基于绝热演化原理的非互易波导理论，设计了一种能在旋转轴上产生动态边界的螺旋结构（SS）。由SS形成的时空拓扑抽运可以实现弹性波在轴内的非互反传输，传输可以实现轴振动的单向隔离。首先，利用传递矩阵法（TMM）从理论上推导了两相螺旋周期轴结构（SPSS）介质的连续性。然后，利用有限元法（FEM）计算SPSS的能带和频响函数。其次，利用有限元法计算结果分析材料参数、几何尺寸等因素对带隙的影响，利用旋转SPSS软件确认时空抽运产生的拓扑边缘模态变化。最后，结合实际轴模型和解析参数确定单向隔振轴的尺寸参数和材料，通过数值模拟得到螺旋轴的振动传递特性，并通过实验验证其单向隔振性能。结果表明，在一定的调制速度下，SS可以实现时空拓扑抽运功能，当带隙在特定的频率范围内偏转时，弹性波可以在偏转的频率范围内单向传播，动态螺旋轴在反向调制时具有良好的单向隔振效果，改变螺旋角速度可以调节弹性波非互反传播的频率范围。该设计可为宽频率范围单向隔振衬套的工程应用提供理论依据。International Journal of PlasticityRole of thermal stress-driven dislocation and low-angle grain boundary migration in surface plastic deformation and grain orientation evolution of tungsten under thermal shockMeng-Chong Ren, Yu-Fei Nie, Han-Qing Wang, Yue Yuan, Fan Feng, You-Yun Lian, Hao Yin, Long Cheng, Duo-Qi Shi, Guang-Hong Ludoi:10.1016/j.ijplas.2024.104205 热应力驱动的位错和低角度晶界迁移在热冲击下钨表面塑性变形和晶粒取向演化中的作用This study reveals that thermal fatigue loading (transient thermal shock), similar to that in fusion environments, can serve as a surface processing technique for BCC metals. Regions with a {110} grain orientation can be selectively achieved in varying sizes and locations on the sample surface. Furthermore, our experiments confirm that the specific localized orientation transformation obtained through this method exhibits certain high-temperature stability at 1573 K (above the recrystallization temperature of tungsten). The experiment employed a 0.25 GW/m² high-energy pulsed electron beam for 1 ms to cyclically load the tungsten surface, simulating edge localized mode events in fusion conditions. It was found that tungsten exhibited significant surface grain orientation transformation (distinct {110} grain orientation) under low strain (∼ 1%) after transient thermal shocks, a phenomenon rarely mentioned in studies of thermal shock on fusion reactor divertor materials. Microstructure characterization results suggest that this localized orientation transformation, induced by minor surface damage, primarily results from the generation, movement, and evolution of dislocations into subgrain and low-angle grain boundaries. The cyclic accumulation of the migration of kink-like subgrain/low-angle grain boundaries under transient thermal stress at high temperatures drives this process. Subsequently, crystal plasticity finite element method simulations based on dislocation slip were conducted to study the surface grain orientation transformation of tungsten under compressive thermal stress. This predictive capability provides valuable guidance for understanding the service conditions of fusion reactor divertor materials. Furthermore, we propose that cyclic transient thermal shocks can serve as an effective surface processing technique for metals, enabling the formation of specific localized grain orientations.本研究表明，热疲劳加载（瞬态热冲击），类似于熔合环境，可以作为BCC金属的表面加工技术。具有{110}晶粒取向的区域可以选择性地在样品表面的不同尺寸和位置上实现。此外，我们的实验证实，通过该方法获得的特定局部取向转变在1573 K（高于钨的再结晶温度）时具有一定的高温稳定性。实验采用0.25 GW/m²高能脉冲电子束循环加载钨表面，模拟聚变条件下的边缘局域模式事件。发现钨在瞬态热冲击后的低应变（~ 1%）下表现出明显的表面晶粒取向转变（明显的{110}晶粒取向），这一现象在聚变反应堆转向器材料的热冲击研究中很少提及。微观结构表征结果表明，这种由轻微表面损伤引起的局部取向转变主要是由位错在亚晶界和低角度晶界的产生、移动和演化引起的。高温瞬态热应力作用下扭结状亚晶/低角度晶界迁移的循环积累驱动了这一过程。随后，采用基于位错滑移的晶体塑性有限元模拟方法，研究了压缩热应力作用下钨的表面晶粒取向转变。这种预测能力为理解聚变反应堆导流器材料的使用状况提供了有价值的指导。此外，我们提出循环瞬态热冲击可以作为一种有效的金属表面加工技术，使特定局部晶粒取向的形成成为可能。Unusual hardening mediated by {10-12} twins of strongly textured titanium at cryogenic temperatureYu Zhang, Danyang Li, Guowei Zhou, Luyang Tao, Zhuangzhuang Liu, Guohua Fan, Hao Wudoi:10.1016/j.ijplas.2024.104206 在低温下，强织构钛的{10-12}孪晶介导了异常硬化{10-12} twinning is an important deformation mechanism for hexagonal metals; however, its characteristically low critical stress and resulting high twin activity often lead to rapid strain localization and premature failure. Therefore, this study aims to strategically delay {10-12} twinning at the initial deformation stage to prevent the strain localization, and concurrently seeks to reactivate {10-12} twinning at the large deformation stage to facilitate continuous hardening. Guided by these dual objectives, we selected rolled titanium as the model material and designed the loading direction to minimize the Schmid factor of {10-12} twinning, and then introduced cryogenic temperatures as low as 77 K to apply GPa-grade stress, thereby enabling continuous strengthening until the reactivation of {10-12} twinning. Under these specified conditions, the rolled titanium exhibited markedly enhanced mechanical properties; the ultimate strength increased from 618 MPa to 1634 MPa, while the true strain was increased by approximately 0.15 when the temperature was reduced from 298 K to 77 K. More importantly, an unusual strain hardening behavior was experimentally observed at a true strain of 0.16, at which {10-12} twins started to behave as the predominant twinning mechanism. Quantitative analysis further indicated that the large majority of the strain hardening capacity was attributed to high-density {10-12} twins. The present study therefore highlighted the pivotal role of {10-12} twins and offers a novel viewpoint for designing and achieving distinctive mechanical properties through the manipulation of deformation twinning.{10-12}孪晶是六方金属的重要变形机制；然而，其低临界应力的特点和由此产生的高孪晶活性往往导致快速应变局部化和过早失效。因此，本研究旨在在初始变形阶段有策略地延迟{10-12}孪晶，以防止应变局部化，同时在大变形阶段重新激活{10-12}孪晶，以促进连续硬化。在这两个目标的指导下，我们选择轧制钛作为模型材料，并设计加载方向以最小化{10-12}孪晶的施密德因子，然后引入低至77 K的低温施加gpa级应力，从而实现持续强化，直到{10-12}孪晶重新激活。在此条件下，轧制钛的力学性能得到了显著提高；当温度从298 K降低到77 K时，合金的极限强度从618 MPa提高到1634 MPa，而真应变提高了约0.15。更重要的是，在0.16的真应变下，实验观察到不寻常的应变硬化行为，此时{10-12}孪晶开始表现为主要的孪晶机制。定量分析进一步表明，绝大多数应变硬化能力归因于高密度{10-12}孪晶。因此，本研究强调了{10-12}孪晶的关键作用，并为通过变形孪晶的操纵来设计和实现独特的机械性能提供了一个新的观点。Temperature-dependent microscopic deformation mechanisms and performance enhancement prospects in high-cycle fatigue of nickel-based single crystal superalloysJiachen Xu, Xinbao Zhao, Jishan Chen, Pengfei Wang, Hao Liu, Wanshun Xia, Quanzhao Yue, Yuefeng Gu, Ze Zhangdoi:10.1016/j.ijplas.2024.104207 镍基单晶高温合金高周疲劳温度相关显微变形机制及性能增强前景Given the limited systematic analysis of microstructural deformation mechanisms in high-cycle fatigue, this study investigates the high-cycle fatigue failure of a fourth-generation nickel-based single crystal superalloy across temperatures of 700°C, 850°C, and 980°C. The results indicate that the alloy exhibits optimal performance at 980°C, followed by 700 °C and then 850°C. At 700°C, stacking fault locks and Lomer-Cottrell dislocations were identified, whereas, at 850°C, elongated stacking fault shearing and typical cross-slip were observed. Notably, at 980°C, intense dislocation activity was detected, including Kear-Wilsdorf locks, dislocation pile-up, and entanglement. The observed changes in microstructural mechanisms with increasing temperature are attributed to elevated stacking fault energy and critical shear stress, alongside reduced critical stress for various dislocation movements. Furthermore, the types of Lomer-Cottrell dislocation and Kear-Wilsdorf lock were accurately identified. In conclusion, the dominant micro-deformation mechanisms—stacking fault locks, Lomer-Cottrell dislocations, and dislocation hardening behaviors such as Kear-Wilsdorf locks—significantly enhance high-cycle fatigue performance. This research addresses the scarcity of studies on microscopic deformation mechanisms in single crystal high-cycle fatigue and provides valuable insights for optimizing the high-cycle fatigue performance of nickel-based superalloys.鉴于对高周疲劳中微观组织变形机制的系统分析有限，本研究研究了第四代镍基单晶高温合金在700°C、850°C和980°C下的高周疲劳失效。结果表明，该合金在980℃时性能最佳，其次是700℃和850℃。在700°C时，发现了层错锁和lomo - cottrell位错，而在850°C时，发现了拉长的层错剪切和典型的交叉滑动。值得注意的是，在980°C时，检测到强烈的位错活动，包括基尔-威尔斯多夫锁、位错堆积和纠缠。观察到的显微组织机制随温度升高的变化归因于层错能和临界剪应力的升高，以及各种位错运动的临界应力的降低。此外，准确地识别了lomo - cottrell位错和Kear-Wilsdorf锁的类型。综上所述，主要的微变形机制——层错锁、lomo - cottrell位错和位错硬化行为（如Kear-Wilsdorf锁）——显著提高了高周疲劳性能。该研究解决了单晶高周疲劳微观变形机制研究的不足，为优化镍基高温合金高周疲劳性能提供了有价值的见解。来源：复合材料力学仿真Composites FEM

【新文速递】2024年12月21日复合材料SCI期刊最新文章

Composite Structures

Composites Part A: Applied Science and Manufacturing

Composites Part B: Engineering

Composites Science and Technology

【新文速递】2024年12月10日固体力学SCI期刊最新文章