冲击作用下PVA-ECC-钢筋复合梁的损伤破坏数值模拟分析

Numerical Simulation Analysis of Damage and Failure of PVA-ECC-reinforced Composite Beams under Impact Loading

目的数值模拟单次冲击和多次冲击作用下的PVA-ECC-钢筋复合梁损伤破坏程度,对比分析素混凝土梁、普通钢筋混凝土梁和PVA-ECC-钢筋复合梁单次和多次冲击作用的动态响应.方法利用ANSYS/LS-DYNA有限元软件分别创建素混凝土梁、普通钢筋混凝土梁和PVA-ECC-钢筋复合梁的有限元实体模型,在进行落锤单次和多次冲击动态响应分析时,考虑不同落锤的冲击高度和冲击速度,跨中最大位移和冲击高度之间关系,冲击耗能、跨中最大位移-冲击次数.结果通过建立相对位移,判定梁的破坏,可知PVA-ECC-钢筋复合梁断裂破坏相比素混凝土梁和普通钢筋混凝土梁在弹性阶段有更小的跨中位移和恢复变形的速度;引入相对耗能值,判定梁的抗冲击耗能性能,PVA-ECC-钢筋复合梁比普通钢筋混凝土结构更具有耗能能力和抗冲击能力.结论通过建立最大位移损伤评估指标,形成了损伤评估等级划分,分别是轻微损伤、中等损伤、严重损伤和破坏失效.

In this paper,the damage degree of PVA-ECC-reinforced composite beams under single and multiple impact is studied by numerical simulation method,and the dynamic response of concrete beams,ordinary reinforced concrete beams and PVA-ECC-reinforced composite beams under single and multiple impact is compared and analyzed.Using ANSYS/LS-DYNA finite element software,three-dimensional solid models of concrete beam,ordinary reinforced concrete beam and PVA-ECC-reinforced composite beam are created respectively.Considering the impact height and impact velocity of different drop hammers,the relationship between the maximum displacement and impact height in the span,the impact energy consumption and the maximum displacement impact times in the span,the dynamic response analysis of single and multiple impact of drop hammer is carried out.The results show that the fracture failure of PVA-ECC-reinforced composite beam has smaller midspan displacement and recovery rate of deformation than that of concrete beam and ordinary reinforced concrete beam in the elastic stage,PVA-ECC-reinforced composite beams have more energy dissipation capacity and impact resistance than ordinary reinforced concrete structures.The maximum displacement damage assessment index is established to form the classification of damage assessment grades,which are slight damage,medium damage,serious damage and failure.