承压反应堆压力容器裂纹前沿约束效应的分析

CONSTRAINT EFFECT ANALYSIS OF THE SEMI-ELLIPTICAL SURFACE CRACK FOR A REACTOR VESSEL SUBJECTED TO PRESSURIZED

基于J-A_2双参数法,通过三维有限元数值模拟,对带有表面半椭圆裂纹的承压反应堆压力容器在高温高压的工况下,即T=561 K,内压p=10 MPa,其裂纹前沿约束效应进行研究。取三组不同裂纹短长轴比a/c=1/2、1/3、1/5(a=20 mm,c=40 mm,60 mm,100 mm),取三组不同材料应变硬化指数n=10、15、20的情况进行了弹塑性分析,得到相对应的J积分和约束参量A_2。研究结果表明:J积分随着短长轴比a/c减小而有所增大,而几乎不受硬化指数n的影响;硬化指数n的增大会弱化a/c对A_2的影响;裂纹最深点(θ=90°)是最危险点处。

The specimen is a reactor pressure vessel with a semi-elliptical surface crack with axial orientation and its 3D finite element numerical modeling is built. Based on J-A2 two parameters method,analysis is performed by considering constraint effect,at T = 561 K,p = 10 MPa. Three different aspect ratio（ a/c） and Ramberg-Osgood exponent（ n） is analylized,namely a/c = 1/2,1/3,1/5（ a = 20 mm,c = 40 mm,60 mm,100 mm） and n = 10,15,20. The corresponding J-integral and constraint parameter A2 is gained. The research results show that： J-integral increases with the decrease of aspect ratio a/c,and RambergOsgood exponent（ n） almost has no effect on J-integral. The increase of Ramberg-Osgood exponent（ n） will weaken the effect of aspect ratio a/c on A2. The most serious point is the deepest point of a crack.