Crack opening and closure in fatigue
Crack opening and closure in fatigue
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DOI：
10.1016/0013-7944(85)90021-9
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发表时间：
1985
影响因子：
5.4
通讯作者：
H. Sehitoglu
中科院分区：
文献类型：
--
作者：
H. Sehitoglu
实验和分析裂纹张开和闭合水平是针对缺口构件中生长的裂纹确定的。实验中使用了复制技术和扫描电子显微镜。分析程序包括确定反向塑性区尺寸、裂纹张开和闭合应力，并基于 Budiansky-Hutchinson 的闭合理论研究。结果一致表明裂纹张开水平高于裂纹闭合水平。在 R=−1 载荷下，钝性缺口构件中的小裂纹表现出比较长裂纹更低的裂纹张开（闭合）水平。然而，对于 R= 0 载荷，随着裂纹长度的增加，裂纹张开（闭合）水平保持相对不变。讨论了裂纹张开和闭合结果对小裂纹行为的影响。附录中介绍了确定裂纹闭合水平的临时方法。建议的方法可以在没有塑性和短裂纹效应的情况下很好地估计裂纹闭合水平，并且可能对工程师和设计师有用。
Experimental and analytical crack opening and closure levels are determined for cracks growing in notched members. Replica techniques and the scanning electron microscope were used in the experiments. The analytical procedure involves the determination of the reversed plastic zone size, the crack opening and closure stresses and is based on Budiansky-Hutchinson's theoretical study of closure. Results indicate consistently that crack opening levels are higher than crack closure levels. Small cracks in bluntly notched members under R=− 1 loading exhibited lower crack opening (closure) levels than longer cracks. However, for R= 0 loading the crack opening (closure) levels remained relatively unchanged with increasing crack length. The implications of crack opening and closure results on the behavior of small cracks are discussed. An ad hoc approach for determining crack closure levels is presented in the Appendix. The suggested method gives good estimates of crack closure levels in the absence of plasticity and short crack effects and may be useful to engineers and designers.