有机玻璃疲劳裂纹扩展定量分析

摘要

采用断裂力学方法分析了有机玻璃裂纹尖端应力分布及银纹微纤化断裂机理，由此建立的力学模型所得到的疲劳裂纹扩展表达式，能较好地拟合有机玻璃疲劳裂纹扩展实验数据。而由裂纹扩展实验数据通过线性回归计算得出的裂纹扩展系数B和理论门槛值ΔKth可分别定量描述有机玻璃在中部区和近门槛区的扩展行为，且B值与有机玻璃拉伸性能之间存在确定的函数关系，认为这两个参数可作为评估有机玻璃疲劳裂纹扩展行为的基本参量。%The mechanism of fatigue crack propagation of organic glass is analyzed by means of the fracture mechanics approach. The formula derived from mechanical model for metals could be introduced for organic glass to fit the test results of fatigue crack propagation (FCP) in near-threshold region and intermediate region. The FCP behavior of near-threshold region and intermediate region can be represented by the value of theoretical FCP threshold and the FCP coefficient which can be calculated by tensile properties of organic glass, respectively. These two parameters could be regarded as quantitative assessing parameters of FCP for organic glass.