三维自适应FE-SPH耦合算法在多层间隔金属靶侵彻问题中的应用

鉴于有限元算法不能有效地模拟侵彻过程所产生的金属碎片, 本文中基于三维自适应FE-SPH耦合算法的基本理论, 自主开发了模拟多层间隔金属靶侵彻问题的三维FE-SPH耦合计算程序。该程序采用四面体单元对多层间隔金属靶侵彻模型进行初始离散, 计算过程中, 当四面体单元等效塑性应变超过某一设定值时, 单元自动转化为SPH粒子, 并引入有限单元-粒子接触算法和耦合算法, 实现大变形和破碎区域采用SPH方法计算, 克服有限元法单元畸变存在的问题。多层间隔靶侵彻算例分析表明, 三维FE-SPH耦合计算程序采用等效塑性应变作为转化判据计算结果较稳定, 并且能够有效地再现侵彻过程中所产生的碎片, 能够模拟侵彻碎片对后层靶的毁伤效应。

Application of 3D FE-SPH adaptive coupling algorithm to penetration analysis of spaced multi-layered metallic targets

As the metal fragments of penetration can not be effectively simulated by finite element method(FEM), a three-dimensional(3D)calculation code was developed to simulate penetration problem of multi-layered spaced metal plates based on theory of 3D FE-SPH adaptive coupling algorithm.Numerical models are approximated initially by tetrahedral elements.When equivalent plastic strain of elements reaches a specified value, they are converted into particles and are calculated by Smoothed Particle Hydrodynamics(SPH)method.Then the regions of large deformation and crush are simulated by SPH method, as SPH method overcome the distortion of elements in FEM.Contact method and coupling algorithm are used to calculate the interface between FEM and SPH method. Two numerical examples are presented to validate the 3D FE-SPH code by representing penetration process of spaced multi-layered metallic targets.The numerical simulation results show that good accuracy and stability are compared to experiment, when equivalent plastic strain is used as criterion of conversion.