裂纹尖端离面变形场的实验测量与数值分析的比较

Comparison of Experimental Measurements and Numerical Analysis of Out-of-surface Deformation around a Crack Tip

用 Nomarski棱镜微差干涉法和有限元方法分别测量和计算了黄铜金属材料 I型裂纹尖端的离面变形场 ,在此基础上对比分析了黄铜材料宏观、细观离面变形的特征。宏观离面变形主要集中发生在裂纹尖端 1 mm2 范围内 ,最大离面变形发生在裂纹尖端。细观离面变形与滑移带、细观组织及细观结构密切相关。晶粒内部的变形导致滑移带出现 ,在滑移带上离面变形有突变。在相邻晶粒之间 ,离面变形连续与否取决于晶粒细观结构的差别。离面变形可以越过晶粒向前传递。实验还发现 。

The out of surface deformation fields around mode I crack tip for brass material are measured by differential interference contrast (DIC) with the help of a Nomarski prism and calculated numerically. On the basis, the characters of out of surface deformation for brass material at macro level and mesoscopic level are analyzed. Out of surface deformation at macro level mainly occurs in the area of 1mm 2 around a crack tip, and the maximum out of surface deformation occurs at the tip of crack. Out of surface deformation at mesoscopic level is closely related to the persistent slip bands (PSB), meso textures and meso structures. Inside a grain, the results of deformation are induced by PSB. There are sudden height changes in PSBs. Among neighboring grains, the successive out of surface deformation depends on the meso structure difference of grains. Out of surface deformation can come across grains. It is also observed during tests that the out of surface deformation in macro shear bands is very apparent.