Fracture and Fatigue of Alloys Under Mixed-Mode Loading

9420511 Hirth本研究考察了混合模式加载对金属合金断裂和疲劳行为的影响。已有基线数据的高纯钢和特殊铝合金是研究的重点。力学性能测量包括I-II-III型复合加载下的低周疲劳和断裂试验，在多轴和非比例加载条件下。用扫描电子显微镜和透射电子显微镜对其变形和断裂行为进行了表征。理论模拟包括通过平移和弯曲的不连续倾斜壁以局部剪切变形的形式对破坏开始的位错模拟的继续。理论工作根据与III型和III型加载组件相关的损伤机制，对裂纹扩展进行了有限元模拟。%这项研究在材料设计标准中具有重要意义，因为它建立了I-II-III复合加载下断裂韧性退化的机理。它还研究了这种载荷在低周疲劳下对损伤的作用。***

9420511 Hirth This research examines mixed-mode loading effects on the fracture and fatigue behavior of metal alloys. A high purity steel and a special aluminum alloy, for which base-line data already exist, are the focus of the study. Mechanical property measurements include low-cycle fatigue and fracture tests under mixed mode type I-II-III loading, with multiaxial and non proportional loading conditions. Deformation and fracture behavior are characterized by scanning electron microscopy and transmission electron microscopy. Theoretical modeling includes a continuation of dislocation modeling of the onset of failure in the form of a localized shear deformation by a translating and bowing discontinuous tilt wall. Theoretical work employs finite element modeling of crack propagation in terms of a damage mechanism associated with the mode II and mode III loading components. %%% This research is of fundamental importance in material design standards since it establishes the mechanism of degradation of fracture toughness under mixed-mode I-II-III loading. It also examines the role of such loading on damage under low-cycle fatigue. ***