SiC/Al梯度功能材料紧凑拉伸试件裂纹扩展分析

Crack Toughness Testing of SiC/Al Functionally Gradient Material Compact Tension Specimen

SiC/Al梯度功能材料各梯度层由不同体积浓度的陶瓷和金属组成,由于材料组分梯度变化,克服了双材料界面的应力突变问题,获得了优异的使用性能。本文首先采用激光云纹干涉法,对具有四个梯度层的SiC/Al梯度功能材料紧凑拉伸试件在机械荷载作用下的拉伸实验位移场进行记录,进而获得紧凑拉伸试件裂纹口位移P-V曲线以及材料断裂韧度实验值;然后根据层合梯度功能材料理论分析模型,建立FGM紧凑拉伸试件的渐近分网有限元平面应变模型,采用通用有限元软件的单元删除模块对试件模型进行裂纹扩展单元的应变模拟分析,从计算所得的裂纹尖端应变图像分析得出梯度材料试件的裂纹扩展规律。

SiC/Al Functionally Gradient Materials have gradient layers made up of different volume concentration ceramic and metal. The large stress changes in the interface of bi-material are avoided because of the gradient of the material property. Moire interferometry was applied to strain distriution test of SiC/ Al functionally gradient material compact tension specimen that has four gradient layers subjectd to mechanicial load. Then the V displacement fields were obtained respectively in the specimens and the P-V curve were obtained to calculate the crack toughness. According to the functionally gradient metrial analysis theory, the transition mapped quadrilateral meshes of the compact tension specimen were obtained. The element deletion mdoels were applied to analyze the crack propagation. The propagation laws were obtained from the crack tip strain field of functionally gradient meterial.