基于FEM-SPH耦合法的弹丸侵彻钢纤维混凝土数值模拟

Numerical simulation for projectile penetrating steel fiber reinforced concrete with FEM-SPH coupling algorithm

针对有限元法(FEM)处理超大变形问题时所存在的困难,基于有限元与光滑粒子流体动力学(Smoothed Particle Hydrodynamics:SPH)的耦合方法模拟了弹丸对钢纤维混凝土的侵彻破坏过程。其中弹丸作为刚体处理并划分成Lagrange标准有限元网格,而靶体中心部分划分成光滑粒子并经历大应变、高应变率和高压作用。为了描述钢纤维混凝土的非线性变形及断裂特性,在计算中引入了Holmquist-Johnson-Cook累积损伤材料模型。数值模拟结果形象再现了弹丸冲击作用下靶体材料破碎、飞溅成坑的物理过程,尤其靶表面碎片飞散的模拟情况与高速摄影照片符合较好,并且侵彻深度计算结果与实验数据具有较好的一致性,FEM-SPH耦合方法显示出了模拟侵彻问题的有效性。研究表明钢纤维能明显增强混凝土基体的抗侵彻性能,且随纤维含量的提高增强效果更佳。

To overcome the difficulty of dealing extra-large deformation problems with finite element method(FEM),projectile penetrating into steel fiber reinforced concrete were simulated using a coupled method between smoothed particle hydrodynamics(SPH)and finite element analysis.The projectiles were treated using standard Lagrangian finite elements and considered as rigid but the targets were divided into SPH grids subjected to large strains,high strain rates,and high pressures.To describe nonlinear deformation and fractureal characteristics of steel fiber reinforced concrete,Holmquist Johnson Cook constitutive relations and damage model were introduced into computations.The numerical simulation revealed well the physical process of experimental damage image of the splash crater formation of the targets.Particularly,the numerical simulation results of concrete debris spattering fit well with the high-speed camera photos.The numerical simulation results of penetration depth agreed well with the experimental data.The study showed that steel fiber has an obvious strengthening effect on concrete targets to resist the penetration of projectiles,and such anti-penetration ability increases with the increase in fiber fraction.