破片与冲击波复合作用下预应力混凝土T形梁损伤分析

Damage Analysis of a Prestressed Concrete T-beam Subjected to Combined Loading of Fragments and Shock Waves

基于ANSYS/LS-DYNA软件建立了预应力钢筋混凝土T形梁、炸药和破片的数值模型,并探究其承受冲击波-破片复合作用时的动态响应及损伤,对研究方法的有效性进行了试验对比验证.分析了冲击波、破片群单独作用及二者复合作用下T形梁损伤和位移响应的异同.运用参数化分析方法,研究张拉控制应力、纵筋配筋率、非加密区箍筋配箍率、混凝土抗压强度、炸药比例距离及爆心位置等因素对T形梁损伤效应的影响,结果表明:随着张拉控制应力、纵筋配筋率及非加密区箍筋配箍率的增加,T形梁的抗爆性能呈现非线性增强;混凝土抗压强度对T形梁抗爆性能增强效果不明显;比例距离相同时,炸药质量比爆心到梁表面距离对梁的毁伤效果影响更为突出,炸药质量越大,T形梁毁伤越严重;当爆心偏离T形梁面正上方时,梁跨中底面横桥向上各点位移峰值从靠近爆心一侧向远离爆心一侧,近似呈均匀增加;爆心偏离中心点距离越小,梁跨中底面位移动态响应越大.

Based on the finite element software ANSYS/LS-DYNA,the numerical models of prestressed concrete T-beams,explosives and fragments are established,and the dynamic response and damage of the beams when subjected to shock wave-fracture composite effects are explored.The effectiveness of the model is verified by test results.The similarities and differences of damage and displacement responses of T-beams under the action of shock wave and fragment group and their combined effects are analyzed.Using parametric analysis methods,the effects of tensile control stress,longitudinal reinforcement ratio,non-encrusted area stirrup reinforcement ratio,concrete compressive strength,explosive proportional distance,and burst position on the damage effect of T-beam were studied.The results show that with the increase of tensile control stress,longitudinal reinforcement ratio and non-densified zone reinforcement ratio,the anti-explosion performance of T-beams appears nonlinear;the compressive strength of concrete has no obvious effect in enhancing the anti-blast performance of T-beams;when the proportional distance is the same,the damage effect of the explosive on the beam is more prominent than the distance from the center of the explosion to the beam surface.The greater the quality of the explosive is,the more serious the damage of the T-beam is;the peak value of the displacement of the mid-span bridge across the upper point increases approximately uniformly from the side close to the blast center to the side away from the blast center;the smaller the distance between the blast center and the center point is,the greater the dynamic response of the beam's mid-bottom surface displacement is.