存在裂纹的压力容器疲劳断裂分析

为了分析工程中常见的破坏性极大的压力容器疲劳问题,基于断裂力学理论将存在初始裂纹的压力容器等效为无穷远处作用均匀拉应力的含中心裂纹无限大板问题,解出表面半椭圆裂纹和穿透裂纹的应力强度因子;利用断裂判据得到裂纹的临界断裂尺寸;采用Paris表达式对裂纹扩展速率进行描述,推导出初始裂纹在不同裂纹尺寸和形式下的裂纹疲劳扩展寿命。结果表明,对于存在不同尺寸和形式裂纹的压力容器,其疲劳寿命可以由裂纹疲劳扩展寿命明确表示,并且为现役压力容器的安全评定提供一定的理论依据。

Fatigue Fracture Analysis of Pressure Vessel with Cracks

In order to study the fatigue of pressure vessel commonly encountered problem in engineering with large destructibility,based on the theory of fracture mechanics,the pressure vessel existing original crack was equivalent to the problem of infinite flat with center crack.The stress intensity factors of infinite flat forced uniform tensile stress at infinite place with surface half ellipse crack and through crack were deduced.The critical crack size can be ascertained by the criterion.Using the Paris expression to analyze the crack extends speed,the crack fatigue extension life of different original crack sizes and forms was deduced.The results show that the fatigue life of pressure vessel with different original crack sizes and forms can be clearly expressed by crack fatigue extension life.These analyzed conclusions provide theoretical reference for the active security assess of using pressure vessel.