表面裂纹准静态扩展的有限元模拟计算

由于现有断裂准则未能考虑表面裂纹前沿各点实际断裂阻力的变化，所作的表面裂纹准静态扩展模拟计算不能很好地预测几何形貌的真实变化规律。本文提出了一个考虑应力状态不同对实际断裂阻力影响的变阻力断裂准则；并以该准则作为表面裂纹前沿局部断裂扩展的判据，通过三维有限元法进行了表面裂纹准静态扩展的模拟计算；还将模拟预测值与用多试件法测得的实验值进行比较，验证了变阻力断裂准则作为裂纹稳态扩展判据的有效性

The finite element simulating calculation of surface crack growth under quasi static loading

The prediction of geometric features of surface crack growth under quasi static loading is recognized as one of the attractive projects in LBB assessment. Since the current fracture criteria do not take the variation of actual fracture resistance in the front of surface crack into account, the simulating calculations could not predict the true geometric features of surface crack growth under quasi static loading very well. In this paper, a new fracture criterion of variable resistance, which will take actual fracture resistance under different stress state into account, is firstly proposed by the authors. Then, the geometric features of surface crack growth under quasi static loading are predicted with 3 D finite element simulation. Moreover, the various parameters during crack growth process are calculated simultaneously. The calculated results are in good agreement with experimental values obtained from multi specimen testing.