高温作用后混凝土损伤动态本构模型研究

Analysis of Dynamic Damage Constitutive Model for Concrete Exposed to High Temperature

为解决高温对混凝土损伤问题,基于混凝土非线性粘弹性本构模型理论及损伤力学有关理论,建立了包含材料参数、动态模量等9个参数的混凝土损伤型动态本构模型,考虑到高温对混凝土动态力学性能影响显著,将高温损伤内化到对本构模型元件材料参数的影响,并根据实验所得数据,拟合得到模型在各温度下的材料参数值;将模型预测应力-应变曲线与实验所得应力应变曲线比较,结果表明:两者的峰值应力误差在5%以内;峰值应变误差在9%以内;弹性模量误差在7%以内,曲线总体拟合相似度在0.93以上,该模型能较好模拟经受高温作用后的混凝土冲击力学特性.

To fill a gap in the field of dynamic constitutive model research of concrete, a dynamic damage constitutive model for concrete was established based on a nonlinear viscoelastic constitutive model and damage mechanics, while considering the effect of damage on the mechanical properties of the material. The proposed dynamic damage constitutive model contained nine parameters such as material parameters and modulus of elasticity. High temperature is considered to directly influence the material parameters of the model, and these model parameters were obtained for various temperatures by fitting the experimental stress-strain curves. The comparison of stress-strain curves between the model predictions and experimental results shows that the error of peak stress, peak strain, and modulus of elasticity is less than 5% , 9% , and 7% , respectively, and the fitting similarities are greater than 0. 93. Consequently, the model can be used to simulate the mechanical behavior of concrete after exposure to high temperatures.