铀铌合金层裂行为的数值模拟

Numerical modeling of spall fracture behavior in U-Nb alloys

采用一种唯象模型来模拟铀铌合金在高应变率条件下的变形行为,该模型包括了材料的非线性弹性(状态方程)、率相关塑性和孔洞的形核及生长等多种效应。并且采用一种对角隐式Runge-Kuta方法来求解本构率方程组,提高了热粘塑性本构关系计算的稳定性及精度。对D.L.Tonks等的铀铌合金平板撞击实验进行了数值模拟,并将计算结果同文献中的实验和数值模拟结果进行了比较。结果表明,本文的计算结果比文献中的数值模拟结果更接近有关实验数据。

A phenomenological model, including nonlinear elasticity （equation of state）, rate-dependent plasticity, and void nucleation and growth, was proposed to simulate deformations of U-6%Nb alloy under the condition of high strain rate. The diagonally implicit Runge-Kutta （DIRK） method was used to solve the constitutive rate equations, and stability and accuracy of the solution to thermoviscoplastic constitutive relations were improved. The proposed model was used to simulate the plate impact experiments on U-6%Nb alloy by Tonks D L, et al. Calculated results by the proposed model are in better agreement with the experimental data than the simulated results by Addessio F L, et al.