钢纤维高强混凝土抗冲击性能的数值仿真

Numerical simulation on impact resistance of steel fiber reinforced high strength concrete

采用显式动力有限元软件LS-DYNA,对钢纤维高强混凝土的霍普金森压杆冲击试验过程进行了数值仿真,混凝土和霍普金森压杆的本构关系分别采用弹塑性流体动力模型和虎克定律描述,钢纤维的增强与增韧作用则通过钢纤维高强混凝土强度与失效应变来体现.结果表明:试件内部应力趋近于均匀之前,经历了初始状态的应力震荡;试件的破坏稍微滞后于应力峰值;相同的冲击速度下,钢纤维高强混凝土试件各个时刻的破坏程度轻于未掺钢纤维的基体混凝土试件,当基体混凝土试件裂成多块时,钢纤维高强混凝土试件还基本保持整体.数值仿真结果与试验结果有较好的相似性,基本能够反映出试件受力与破坏的特征.

By explicit dynamic finite element software of LS-DYNA,the split hopkinson pressure bar（SHPB） impact experiment of steel fiber reinforced high strength concrete（SFRHSC） were numerically simulated.Elastic-plastic hydrodynamic model and Hooke′s law were adopted to describe the constitutive relations of concrete and SHPB,respectively.The reinforcing and toughening effects of steel fiber on concrete were characterized by strength and failure strain of SFRHSC,respectively.The results show that internal stress of specimens oscillate initially before reaching stress equilibrium.Failure process of specimens are slightly delayed to their peak stress.The fracture of specimens matrix are more severe than that of SFRHSC specimens at any time.At the same impacting velocity,the cracks propagate in SFRHSC spe-cimen with overall unchanged shape,while the specimens matrix are broken into many pieces.The numerical simulation results exhibite good consistency with those of experiment,and can basically reflect the characteristic of dynamic load and specimens failure during SHPB impact experiment.