三维疲劳裂纹扩展仿真的双重边界元法

运用双重边界元方法求解三维疲劳裂纹前沿的应力应变场,基于Forman理论、最小应变能密度法和Elber模型,采用增量步裂纹扩展分析方法,并根据裂纹几何形状的改变,对裂纹面进行网格重划分和迭代计算,模拟了三维裂纹的扩展和预测裂纹扩展寿命.获得了裂纹前沿各点的扩展长度、扩展方向和应力强度因子等特征量.扭力轴表面裂纹扩展的应用实例表明该方法正确合理.

Dual boundary element method of three-dimensional fatigue crack growth

Using dual boundary element method, stress and strain fields are computed along the three-dimensional fatigue crack fronts. The simulation of the tllree-dimensional crack growth and the prediction of fatigue lives are achieved using an incremental crack extension analysis based on the Forman law, minimal strain energy density criterion and Elber model. According to the change of crack geometry, on the crack surface elements are redivided and iteratively calculated. Extension size and growth direction and stress intensity factors along the crack fronts ale obtained. The capability of the method is demonstrated by solving the surface crack propagation of a torsion shaft example.