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材料在动载特别是在高应变率载荷作用下的性质,和静载下是很不相同的,这一点已为人们所公认。von Karman等在40年代所建立的塑性波理论曾在材料动态性质研究上起过重大作用。但它以所谓“应变率无关”假设为前提,不尽合理。事实上,材料的应力、应变关系不仅随应变率而异,不能统一为一个单一的应力、应变关系,而且还与应变率历史有关。这一方面,J.Duffy,U.S.Lindholm以及J.D.Campbell等已做了不少实验和理论分析工作,特别是在铜和铝上取得详尽的数据,并在热激活理论基础上探讨了建立本构方程的问题。
It is well-established that the properties of materials under dynamic loads, especially at high strain rates, are very different from those under static loading. The plastic wave theory established by von Karman and others in the 1940s played an important role in the study of the dynamic properties of materials. However, it is based on the assumption that the “strain rate has nothing to do”, which is not reasonable. In fact, the stress-strain relationship of the material not only varies with the strain rate, but also can not be unified into a single stress-strain relationship, but also with the strain rate history. In this regard, J. Duffy, US Lindholm and JD Campbell have done a lot of experimental and theoretical analysis, especially on copper and aluminum to obtain detailed data, and based on the theory of heat activation to explore the constitutive equation The problem.