基于OTTOSEN准则的混凝土粘塑性力学模型

研究了混凝土的弹．粘塑性动态本构关系，提出一个应变率相关的非线性混凝土模型．模型改进Bicanic的混凝土塑性间断面变化规律和Ottosen的四参数屈服准则，建立冲击荷载下的混凝土本构方程，可以应用于地震和爆炸作用下混凝土材料响应的研究．根据混凝土动态实验结果对应变率和材料强度的关系提出合理假设，考虑以往被忽略的材料峰值应变和泊松比随应变率的变化．模型包含静水压力参数和动态塑性损伤因子，可以有效地反映混凝土的动态力学行为，为其动态问题的研究提供有益的思路和有效的工具．

A VISCOPLASTIC MODEL FOR CONCRETE BASED ON OTTOSEN'S CRITERION

Some dynamic constitutive properties of concrete are studied on the basis of elasto viscoplastic laws, and a nonlinear rate dependent model is established in this paper. The model is developed from the principles of inelastic discontinuities proposed by Bicanic, and Ottosen's four parameter criterion is adopted to improve the performance of the constitutive model subject to impact loading. The variations of critical strain and elastic modulus under different strain rates are also considered. It can be applied to the prediction of dynamic response of concrete under both seismic and explosive loading. The hydrostatic pressure and dynamic plastic damage are incorporated here, so that the dynamic response might be effectively delineated, concomitant with in structive thoughts and practical tools provided.