混凝土率相关单轴塑性损伤本构的开发及应用

Development and Application of Rate-dependent Uniaxial Plastic Damage Model of Concrete

为了对爆炸作用下钢筋混凝土(reinforced concrete,RC)构件动力响应进行简化分析,需要合理描述混凝土和钢筋的应变率效应,而LS-DYNA中缺乏能够考虑混凝土应变率效应的单轴本构模型,因此,结合Faria单轴塑性损伤模型,通过黏性规则化方法调整率无关模型的损伤阈值演化律以考虑应变率效应,并利用LS-DYNA将该模型编制为用户材料子程序VUMAT.以单个单元测试了高应变率下材料的基本性能;基于纤维模型模拟了RC梁在爆炸、冲击作用下的动力响应.结果表明:该本构模型能反映混凝土受拉应变率效应高于受压应变率效应的事实,同时也能较准确地模拟爆炸与冲击作用下RC梁的动力响应.

It is required to consider the strain rate effect of concrete and steel reinforcement appropriately in order to conduct simplified analysis of reinforced concrete( RC) members under blast loading,while there is a lack of concrete uniaxial constitutive model that can be used to model strain rate effect in LSDYNA. In this paper,based on Faria 's uniaxial plastic damage model,the strain rate effect is considered by adjusting the damage thresholds of rate-independent model through viscous regularization,and then the model is worked out as a user defined material subroutine VUMAT. The basic ratedependent properties are tested by a single element model and the dynamic response of RC beams under blast and impact loading are modeled on the basis of fiber model. Results show that the constitutive model can reflect the fact that strain rate effect under tension is higher than that under compression,and can model the dynamic response of RC beams under blast and impact loading accurately.