【摘要】 在重建Cochran-Banner模型的基础上提出了一种新的概念性层裂模型。这种新模型仅保留CochranBanner模型中的强度函数,重新定义损伤,并抛弃了基本假设:一旦微损伤形成,使微损伤演化远远易于使固体进一步体积应变,进而修正了差分微元中固体比容的计算。在新的模型中,一旦拉伸应力达到层裂强度,重新定义的损伤将由强度函数确定的应力松弛方程、计及损伤的能量守恒方程、状态方程以及本构方程等一系列封闭方程组确定。新模型中也仅包含两个参数:层裂强度及临界损伤度,它们的确定能使在一定初、边值条件下的层裂试验的数值计算结果与实验测得的靶自由面速度历史或靶低阻抗界面应力历史以及回收观测的层裂面上的损伤一致。强调指出,选定强度函数或应力松弛方程提供了确定损伤的可能,同时排除了任何外加的损伤演化方程。更多还原

【Abstract】 A new conceptual model to describe spallation was presented basing on the original Cochran-Banner spall model.The strength function given by Cochran-Banner was maintained using the redefined damage,and the correction concerning the volume of the mesh cells was realized considering it unnecessary to expect that it is much easier to open microcracks once they are formed than to strain the solid further.Once the spall strength was reached,the damage in the new conceptual spall model would be only determined by a series of closed equations including the stress relaxation relationship given by the strength function,the energy conservation equation,the equation of state,and the constitutive equations for the damaged aggregate.The new conceptual spall model contains only two parameters:the spall strength and the critical damage,the determination of which should make the computed results of spall tests under the appropriate initial and boundary conditions consistent with the experimental free surface velocity profile of target or the stress profile of interface between target and low impedance buffer and the observed damage at spall plane for spall tests.It is worth to note that choosing a strength function or a stress relaxation equation provides a possibility of determining the damage and excludes any extra equation of damage evalution.更多还原