基于混凝土材料强冲击加载下的试验研究,提出了两种损伤型动态本构模型:损伤型黏弹性本构模型和损伤与塑性耦合的本构模型.通过模型计算结果与冲击试验结果的比较可发现,随着冲击速度的提高,混凝土材料内部产生了显著的塑性变形,由此损伤型黏弹性本构模型的应用就存在一些不足.而损伤与塑性耦合的本构模型由于考虑了裂纹扩展引起的材料强度和刚度的弱化,以及微空洞缺陷塌陷引起的塑性变形,因而能更好地用于模拟强冲击载荷作用下混凝土材料的冲击响应特性.
This paper presents two damage constitutive models, namely, the damage visco-elastic constitutive model and the coupled constitutive model of damage and plasticity, to describe the impact behavior of concrete. A comparison between the model prediction and the experimental results shows that the damage visco-elastic constitutive model is not adequate to describe the plastic deformation in concrete, with increase of impact velocity. The damage constitutive model coupled with plasticity accounts for such effects as modulus degradation due to micro-cracking, the increase of bulk modulus and plastic strain due to micro-voids collapse. Therefore, it describes very well the impact behavior of concrete subjected to shock loading.