RIA: Experimental Simulation of Crack Initiation at Bimaterial Interfaces due to Mechanical and Thermal Loads

将进行实验研究，研究材料界面在机械和热载荷作用下的准静态和动态裂纹萌生和扩展。该研究将有助于更好地理解控制多相材料断裂行为的界面破坏机制，如聚合物和金属基复合材料、金属填充复合材料以及基板上的粘合键和薄膜。所提出的工作是关于双材料样品在受控加载条件下的裂纹萌生和扩展模拟。界面裂纹尖端的变形将在断裂开始前和开始时进行光学测量。一种新开发的实时、全场光学技术“相干梯度传感”（CGS）将被用作测量界面裂缝附近变形的实验工具。从这些高分辨率的光学测量中，可以推断出局部裂纹尖端参数，如复杂应力强度因子和裂纹尖端模式混合。光学测量将使我们能够寻求局部裂纹尖端参数与外部/材料参数（如远程加载和材料属性不匹配）之间的关系。这将为识别显著影响界面裂纹萌生的参数和建立界面失效准则提供有价值的数据。

Experimental research, dealing with quasi-static and dynamic crack initiation and growth at material interfaces subjected to mechanical and thermal loading, will be carried out. The research will contribute to a better understanding of interfacial failure mechanisms which predominantly control the fracture behavior of multi-phase materials such as polymer and metal matrix composites, metal filled composites, and of adhesive bonds and thin films on substrates. The proposed work is concerned with crack initiation and growth simulations under controlled loading conditions in bimaterial specimens. Interfacial crack tip deformations will be optically measured prior to and at fracture initiation. A newly developed, real time, full field optical technique, 'Coherent Gradient Sensing' (CGS), will be utilized as an experimental tool for measuring deformations near interfacial cracks. From these high resolution optical measurements, local crack tip parameters such as complex stress intensity factor and crack tip mode mixity will be inferred. The optical measurements will allow us to seek relationships between the local crack tip parameters and external/material parameters such as remote loading and material property mismatch. This will provide valuable data for identifying parameters which significantly influence crack initiation at interfaces and for establishing interfacial failure criteria.