Variation of mixed modes stress intensity factors of an inclined semi-elliptical surface crack
Variation of mixed modes stress intensity factors of an inclined semi-elliptical surface crack
复制标题
倾斜半椭圆表面裂纹混合模式应力强度因子的变化
DOI：
10.1023/a:1018666110597
复制
发表时间：
1999
影响因子：
2.5
通讯作者：
Makoto Yagishita
中科院分区：
文献类型：
--
作者：
N. Noda;Kimihiro Kobayashi;Makoto Yagishita
本文应用奇异积分方程法计算了受拉半无限体中三维倾斜半椭圆表面裂纹沿着裂纹前缘的应力强度因子。半无限体中位移不连续引起的应力场被用作基本解。然后，这个问题被表述为一个积分方程组，其奇异性为r-3。在数值计算中，用基本密度函数和多项式的乘积近似未知的体力偶。结果表明，对于各种几何条件，本文方法都能精确地得到复合型应力强度因子沿裂纹前缘沿着方向的平滑变化。在分析中考虑了倾斜角、椭圆形状和泊松比的影响。裂纹口张开位移以图形显示，以预测裂纹深度和倾角。当倾角为60 °时，在靠近自由面的有限区域内，Ⅰ型应力强度因子FI为负值。因此，实际裂纹表面似乎在表面附近彼此接触。
In this paper, a singular integral equation method is applied to calculate the stress intensity factor along crack front of a 3D inclined semi-elliptical surface crack in a semi-infinite body under tension. The stress field induced by displacement discontinuities in a semi-infinite body is used as the fundamental solution. Then, the problem is formulated as a system of integral equations with singularities of the formr−3. In the numerical calculation, the unknown body force doublets are approximated by the product of fundamental density functions and polynomials. The results show that the present method yields smooth variations of mixed modes stress intensity factors along the crack front accurately for various geometrical conditions. The effects of inclination angle, elliptical shape, and Poisson's ratio are considered in the analysis. Crack mouth opening displacements are shown in figures to predict the crack depth and inclination angle. When the inclination angle is 60 degree, the mode I stress intensity factorFIhas negative value in the limited region near free surface. Therefore, the actual crack surface seems to contact each other near the surface.