摘要
导致加载序列作用的加载历史极大地影响着变幅加载下的疲劳裂纹扩展行为。本研究完成了一个恒幅及简单变幅加载历程下的探索性试验研究计划,以进一步了解序列影响并提供一个评价和改进现有裂纹扩展预测方法的基础。本研究的第一部分是进行宽范围应力比下的恒幅裂纹扩展试验。试验结果以及试验期间断口型态的转变可以在有效应力强度因子范围△Keff 的基础上来表示。第二部分是进行系统变化高载、低载以及卸载的简单序列下的裂纹扩展试验,测量裂纹扩展行为。最后提出关于预测模型的进一步发展的一般性看法。
Fatigue crack propagation behaviour under variable amplitude loading is si- gnificantly influenced by load history induced sequence effects.In the present in- vestigation an exploratory test program with simple variable amplitude load sequ- ences was performed,which was designed to improve the general understanding of sequence effects and to offer a basis both for an evaluation of existing crack propagation prediction models and for the development of improved methods. In the first part of the study constant amplitude tests were performed over a wide range of R-ratios.The test results and the transition of the fracture mode during tests could be represented on the basis of the effective ΔK-value. In the second part of the paper tests with simple systematically varied sequ- ences of high loads,low loads and underloads were performed and the crack pro- pagation behaviour was measured.Finally,some general viewpoints regarding further developments of models are outlined.
出处
《航空材料学报》
EI
CAS
CSCD
1989年第4期46-56,共11页
Journal of Aeronautical Materials
