FRP筋与水泥浆界面粘结滑移特性数值模拟研究

Numerical simulation study on bond-slip performance between FRP bar and cement slurry

基于试验和数值模拟方法研究FRP筋与水泥浆的粘结特性与不同因素对其粘结行为的影响.以有限元软件中的Cohesive单元模拟FRP筋与水泥浆之间的界面粘结滑移,以混凝土塑性损伤模型模拟水泥浆体的损伤与破坏行为.按试验工况及加载条件建立FRP筋-水泥浆界面粘结滑移模型.通过控制变量法研究了FRP筋类型、直径、长度等因素对界面粘结行为、粘结应力分布和破坏机制的影响。结果表明:不同纤维材料的粘结性能差异较大;增大粘结长度、筋材直径能够提高极限承载力;在加载过程中,FRP筋体轴力主要分布在加载端,随着荷载增加,靠近加载端的筋体轴力增幅大于粘结段末端;拉拔荷载达到峰值时,界面粘结单元开始破坏、界面粘结单元发生损伤,粘结强度不断下降;随着粘结-滑移曲线进入下降段,界面粘结作用逐渐失效,构件完全破坏.

In this paper,the bond-slip performance between FRP bar and cement slurry and the influence factors on the bond performance were studied by numerical simulation and indoor test.Cohesive unit the finite element software was used to simulate the interface bond slip between FRP bar and cement slurry,and the damage and destruction behavior of cement slurry was simulated by the concrete plastic damage model.The influence factors such as FRP bar type,diameter,and length on interface bond behavior,bond stress distribution,and failure mechanism was studied through controlled variable method.The results show that the bond performance of different types of FRP bars varies greatly.Increasing the bond length and diameter of FRP bar can improve the ultimate bearing capacity.During the loading process,the axial force of FRP bar is mainly distributed at the loading end.As the load increases,the increase in axial force of the FRP bar near the loading end is greater than that at the end of the bonding section.When the pull-out load reaches its peak,the interface bond unit is damaged,and the bond strength continuously decreases.As the bond slip curve enters the descending stage,the interface bond strength gradually fails and the specimen is completely destroyed.