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本文针对Ti-6Al-4V钛板的超载试验,着重研究了不同超载比及不同裂纹长度下的超载迟滞特性,讨论了影响迟滞效应的一些主要因素。认为迟滞效应是循环载荷之间交互作用的结果,并提出了迟滞过程可以分为五个阶段的看法。通过对裂纹扩展形式等因素的分析,认为本试验的疲劳裂纹扩展的超载过程,属于平面应变或以平面应变为主的混合型;在平面应变条件下,对于给定的Q_(o1)超载引起的迟滞循环数N_o,随着超载水平K_(o1)的减小而增加。 从应用观点出发,选择了Wheeler模型、Willenborg模型、Matsuoka模型和Maarse模型,从各模型对迟滞现象的解释能力、应用情况等方面作了较全面的比较和讨论。认为以闭合效应为基础的Matsuoka模型与实际情况符合较好;并发现各模型计算中所假定的迟滞影响区,均比实测的超载迟滞影响区要小得多。
In this paper, Ti-6Al-4V titanium plate overload test, focusing on different overload ratio and different crack length overloading hysteresis characteristics discussed some of the main factors that affect the hysteresis effect. It is considered that the hysteresis effect is the result of the interaction between cyclic loads and proposes that the hysteresis process can be divided into five phases. Based on the analysis of the crack propagation forms and other factors, it is considered that the overloading process of fatigue crack growth in this experiment belongs to the plane strain or the plane strain-based mixed type. Under the plane strain condition, for a given Q_ (o1) overload The number of hysteresis loops N_o increases as the overload level K_ (o1) decreases. From the application point of view, the Wheeler model, the Willenborg model, the Matsuoka model and the Maarse model are selected, and a comprehensive comparison and discussion are made on the hysteresis interpretation ability and application from each model. It is considered that the Matsuoka model based on the closure effect is in good agreement with the actual situation. It is also found that the hysteresis affected zone assumed in each model calculation is much smaller than the measured hysteresis zone.