冲击荷载作用下混凝土动态力学性能数值模拟研究

NUMERICAL SIMULATION RESEARCH ON DYNAMIC MECHANICAL BEHAVIORS OF CONCRETE SUBJECTED TO IMPACT LOADING

利用直锥变截面式Φ74mm SHPB对混凝土和水泥砂浆进行三种不同冲击速度下动态力学性能实验,分析冲击速度对混凝土动态力学性能影响规律.应用刚性板冲击加载方式进行混凝土动力响应数值模拟研究.数值模拟表明:混凝土峰值应力随着冲击速度增大而增大,是一种率敏感材料;随着粗骨料体积含量增大,冲击荷载作用下混凝土峰值应力呈现先增大后减小趋势,粗骨料体积含量为40%时混凝土峰值应力最大;保持粗骨料最大粒径25mm不变,随着粗骨料最小粒径增大,混凝土峰值应力逐渐减小;保持粗骨料最小粒径5mm不变,随着粗骨料最大粒径增大,混凝土峰值应力呈现先增大后减小趋势,数值模拟结果为混凝土工程应用提供理论依据和技术支撑.

SHPB with the diameter of 74 mm was used to study the dynam!c mechanical behaviors of cement mortar and concrete under different impact velocities. The influence of impact velocity on the mechanical behaviors of concrete was analyzed. The dynamic response of concrete loaded by rigid slab was simulated. Numerical simulation shows that the peak stress of concrete increases with impact velocity, so concrete is rate-dependent. With the increase of the volume fraction of coarse aggregate, the peak stress of concrete increases firstly, then declines. When the volume fraction of coarse aggregate is equal to 40%, the peak stress of concrete reaches maximum value. Under the condition that the maximum diameter of coarse aggregate 25 mm is kept unchanged, the peak stress of concrete declines with the minimum diameter of coarse aggregate decreasing. However, under the condition that the minimum diameter of coarse aggregate 5 mm is kept unchanged,with the increase of the maximum diameter of coarse aggregate, the peak stress of concrete increases firstly, then declines, which provides theoretical guidance for the engineering application of concrete.