基于Weibull统计理论的混凝土率型损伤本构模型研究

为研究混凝土在股役期间的材料特性,进行了不同应变速率下(10^-5,10^-4,10^-3和10^-2/s)的混凝土单轴受压试验,分析了混凝土材料基本力学特性,试验结果表明:随着应变速率的提高,峰值应力和初始弹性模量呈现增大的趋势,峰值应力的变化规律并不明显。基于Weibull和Lognormal统计分布理论,以及Lemaitre应变等效原理,引入应变速率因素,构建出混凝土材料分段式率型单轴受压损伤本构模型。依据试验数据,确定了所建立的率型损伤本构模型参数;给出了不同速率下混凝土单轴受压应力-应变和损伤变化规律曲线。结果表明:建立的混凝土率型本构模型能够反映不同应变速率下混凝土单轴受压损伤全过程。

Rate-dependent Constitutive Model of Concrete Based on the Statistical Theory of Weibull

Through uniaxial compression tests under different strain rates(10^-5,10^-4,10^-3 and 10^-2/s), the mechanical properties of concrete are analyzed to obtain the material properties of concrete during operation. Results show that as strain rates increase, the peak stress and initial elastic modulus tend to increase, but the regularity of peak strain’s variation is not obvious. With strain rate sensitivity into consideration, a rate-dependent segmented constitutive model of concrete is established based on Lemaitre’s strain equivalent principle and the statistical distribution theories of Weibull and Lognormal. On the basis of test data, the model parameter is determined under different strain rates, and the curve of uniaxial compression stress-strain and the curve of damage variation are obtained. The results indicate that the rate-dependent constitutive model could reflect the whole process of the concrete’s damage of uniaxial compression under different strain rates.