Stress-intensity Factors for Circumferential Surface Cracks in Pipes and Rods under Tension and Bending Loads
Stress-intensity Factors for Circumferential Surface Cracks in Pipes and Rods under Tension and Bending Loads
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DOI：
10.1520/stp17428s
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
I. Raju;J. Newman
中科院分区：
文献类型：
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作者：
I. Raju;J. Newman
本文的目的是提出一个广泛的近半椭圆形表面裂纹的管道和棒材的应力强度因子。这些结构承受远程拉伸或弯曲载荷。对于管道，裂纹深度与裂纹长度之比（a/c）范围为0.6至1;裂纹深度与壁厚之比（a/t）范围为0.2至0.8;内半径与壁厚之比（R/t）范围为1至10。对于棒，裂纹深度与裂纹长度的比率也在0.6至1的范围内;并且裂纹深度与棒直径的比率（a/D）在0.05至0.35的范围内。选择这些特定的裂纹构型以涵盖在拉伸和弯曲疲劳载荷下对管道和杆进行的实验中观察到的裂纹形状（a/c）的范围。用三维有限元法计算了应力强度因子。有限元模型采用沿裂纹前缘沿着的奇异单元和其它地方的线性应变单元。这些模型有大约6500个自由度。应力强度因子的评估使用的是一个持久力的方法。
The purpose of this paper is to present stress-intensity factors for a wide range of nearly semi-elliptical surface cracks in pipes and rods. The configurations were subjected to either remote tension or bending loads. For pipes, the ratio of crack depth to crack length (a/c) ranged from 0.6 to 1; the ratio of crack depth to wall thickness (a/t) ranged from 0.2 to 0.8; and the ratio of internal radius to wall thickness (R/t) ranged from 1 to 10. For rods, the ratio of crack depth to crack length also ranged from 0.6 to 1; and the ratio of crack depth to rod diameter (a/D) ranged from 0.05 to 0.35. These particular crack configurations were chosen to cover the range of crack shapes (a/c) that have been observed in experiments conducted on pipes and rods under tension and bending fatigue loads. The stress-intensity factors were calculated by a three-dimensional finite-element method. The finite-element models employed singularity elements along the crack front and linear-strain elements elsewhere. The models had about 6500 degrees of freedom. The stress-intensity factors were evaluated using a nodal-force method.