混凝土动态力学性能数值模拟研究

Numerical Simulation of Dynamic Mechanical Properties of Concrete

数值模拟是研究混凝土动态力学性能主要手段之一。编写二维混凝土多边形粗骨料随机分布程序,利用大型有限元软件ANSYS/LS-DYNA对直径74mm、高70mm混凝土在不同冲击速度下的动态响应进行模拟,分析冲击速度、粗骨料最大粒径、最小粒径和体积含量对多边形粗骨料混凝土动态特性影响,考察多边形粗骨料混凝土动态破坏模式。数值模拟表明:混凝土表现出明显的率敏感性;随着粗骨料颗粒最小粒径增大,多边形粗骨料混凝土峰值应力逐渐减小;随着粗骨料颗粒最大粒径增大,多边形粗骨料混凝土峰值应力呈现先增大后减小趋势;当粗骨料体积含量小于40%时,随着粗骨料体积含量增加,多边形粗骨料混凝土峰值应力逐渐增大,当粗骨料体积含量大于40%时,随着粗骨料体积含量增加,多边形粗骨料混凝土峰值应力逐渐减小。

Currently,numerical simulation is one of the main means to study the dynamic mechanical properties of concrete.A two-dimensional polygonal distribution program of coarse aggregate was designed to simulate the dynamic response of 74 mm-diameter and 70 mm-height concrete specimen under different impact speeds by means of ANSYS/LS-DYNA software.The influences of impact speed,maximum value of particle size,minimum value of particle size and distribution of polygonal coarse aggregate and volume fraction of polygonal coarse aggregate on the dynamic mechanical properties of concrete were analyzed.At the same time,the dynamic failure mode of polygonal coarse aggregate concrete was discussed.Simulated results show that concrete is ratedependent.With the increase of minimum value of particle size of polygonal coarse aggregate,the peak stress of concrete declines.Whereas,with the increase of maximum value of particle size of coarse aggregate,the peak stress of concrete increases firstly,then declines.When the volume fraction of coarse aggregate is less than 40%,the peak stress of concrete increases with the volume fraction of coarse aggregate.Whereas,when the volume fraction of coarse aggregate is more than 40%,the peak stress of concrete declines with the volume fraction of coarse aggregate.