钢筋混凝土梁受弯破坏过程的细观数值模拟研究

Mesoscale simulation of the flexural failure process of reinforced concrete beams

在细观层次上将混凝土视为由粗骨料、硬化水泥砂浆及界面粘结带组成的三相非均质复合材料,能够较好地模拟混凝土加载时的裂缝扩展过程和分布规律。本文采用细观刚体弹簧元法模拟了钢筋混凝土梁的弯曲受力性能和破坏过程,加载方式采用两点对称加载。数值计算得到了钢筋混凝土梁的破坏形态和荷载-变形曲线,并分析了受力过程中纵向钢筋的应力变化。与试验结果对比表明,细观刚体弹簧元法可以有效模拟钢筋混凝土梁的裂缝开展过程、破坏形态和荷载-变形响应。

On mesoscale, concrete is usually regarded as a three-phase composite material, consisting of coarse aggregates, mortar and the bond zone. This treatment can represent well the crack propagation and distribution under loading. By means of the mesoscopic RBSM （Rigid-Body-Spring Model）, this paper numerically simulates the mechanical behavior and failure process of reinforced concrete （RC） beams with symmetrically loading at two positions on the beam. The crack pattern and load-deflection curve under different reinforcement ratios are simulated. In addition, the stress distribution of the longi- tudinal reinforcement is analyzed during the loading process. Compared with the experimental results, it is shown that the RBSM on mesoscale can be applied to simulate the cracking propagation,failure mode and load-deflection behavior of RC beams.