功能梯度材料静态断裂的CGS方法实验研究

Experimental study of coherent gradient sensing(CGS) on static crack in functionally gradient materials

利用相干梯度敏感方法对功能梯度材料I型静态断裂特性进行实验研究,并利用有限元软件进行数值模拟.假设材料性能沿裂纹方向分别按两种不同的规律变化:1)弹性模量和密度指数规律变化;2)弹性模量线性变化,密度保持常数.保持泊松比不变,首先推导两种变化规律功能梯度材料I型静态裂纹的相干梯度敏感方法控制方程;然后根据实验结果,提取应力强度因子等断裂参数,分析不同梯度变化规律对材料断裂性能的影响;最后与有限元模拟计算结果相结合,对功能梯度材料I型静态裂尖的K主导区范围进行了分析.

Coherent gradient sensing （CGS） is introduced to study static crack of mode-Ⅰ in functionally gradient materials. And the numerical simulation is analyzed through finite element method. Two types of property variations in the direction of crack propagation are studied ： （ 1 ） linear variation of the shear modulus with constant mass density; （2） exponential variation of shear modulus and mass density. The Poisson＇ s ratio is assumed to be constant. Firstly, the CGS governing equations at the mode-Ⅰ static crack tip in two kinds of FGMs are developed. Then based on the results of the experiments, the stress intensity factors are calculated. And the influences of the property variation on the fracture characteristic are analyzed. Finally, combining the results of FEM, the K-dominant of mode-Ⅰ static crack tip in FGMs is discussed in detail.