【摘要】 采用内参量热力学方法讨论弹性—理想塑性体的裂纹扩展,主要在下两方面有更进一步的理论分析。一是对弹塑性断裂力学中的各种能量关系作出了统一的整理,讨论了弹塑性裂纹体的裂纹扩展和塑性变形的驱动力与阻尼力,并给出了相应的过程准则表达式以及能用于弹塑性柔度标定的计算公式。二是以中心裂纹体为例,分析了裂纹扩展的热力学稳定性条件,明确弹塑性裂纹扩展的热力学稳定性的全局性条件是不能满足的,然后转而结合具体的极限势函数方程来讨论恒位移状态下满足稳定性的局域性条件的各有关情况,区分出裂纹失稳扩展—止裂、明显稳定扩展(撕裂)和缓慢稳定扩展三种情况,并举例给出了应变—裂纹长大和应力—应变的计算曲线。更多还原

【Abstract】 The crack propagations of elastic-perfect plastic crack bodies are discuss- ed by means of internal variable thermodynamics.The main results are the theoretical analyses of following two areas.The first is the energy relation- ships appeared in EPFM,including the driving and resisting forces of crack extension and plastic deformation,the process criteria equations and the com- pliance equation in the elastic-plastic condition.The second is the thermody- namic stability investigation for a central crack sample as a example.The results show that the stability condition in the situation as a whole are not satisfied in both constant load and constant displacement.In order to obtain the stability conditions in the situation as a part in constant displacement, some possible limit potential fuctions of crack extension and plastic deforma- tion are compared,and two reality functions are analysed in more details. Three types of crack growth as slow-stable,fast-stable—tearing and fast-inst- able—pop-in have been distingushed.As a example,a group of theoretical strain-crack growth and stress-strain curves are given in this paper.更多还原