基于有限元法对裂纹尖端应力强度因子的计算分析

Calculation and Analysis of Crack Tip Stress Intensity Factor Based on Different Finite Element Methods

应力在裂纹尖端会出现无限大的奇异性,但应力强度因子K则为有限值,是表征裂尖应力场强弱的物理参量。采用J积分法,位移外推法和相互作用积分法等3种不同的方法计算断裂模型裂尖的K值,并研究了受力、裂纹长度、含裂纹构件的几何参数等对裂纹尖端应力强度因子的影响。结果表明3种方法模拟出的K值结果一致性较好,与应力强度因子手册值相比都能达到较高精度。对照3种方法,分析出各种方法的优胜劣汰,对应用数值法计算应力强度因子方法的选择具有借鉴和参照作用。

The stress state at crack tip shows infinite singularily,but the stress intensity factor K is limited value,which represents its physical parameters to describe the strength of crack tip stress field.This paper uses three methods of J-integration,displacement extrapolation and interaction integraltion to calculate the K value on the crack tip and research on the influence of load,length of crack and geometric parameters of cracked parts on stress intensity factor.The results indicate the stress intensity factor calculated by three methods is greatly consistent,and compared with the value in the stress intensity factor handbook,it is of the higher precision.It also analyses the advantages and disadvantages of the of three methods.The reference is given to choosing the method which is used to calculate the stress intensity factor.