受火(高温)后混凝土的随机损伤本构关系

结合受火(高温)后混凝土的损伤形态和破坏特征,研究了基于损伤随机演化下受火(高温)后混凝土受拉和受压损伤发展的随机演化规律.引入弹簧损伤单元模型,考虑混凝土初始损伤、受火损伤及裂缝闭合下损伤愈合等因子,利用Weibull分布函数进行推演,建立了受火后混凝土单轴抗拉、单轴抗压的随机损伤本构关系模型.通过计算结果与试验数据的对比验证,从理论结果而非试验数据的拟合上解释了受火(影响)后混凝土应力-应变的四大特点,证实了运用随机损伤本构关系反映受火后混凝土破坏机理的可行性.

Stochastic Damage Constitutive Law for Fire damaged Concrete

Based on the damage configuration and failure feature of fire-damaged concrete,this paper presents studies of the stochastic evolution law of fire-damaged concrete(FDC) under uniaxial tension and uniaxial compression.The stochastic damage constitutive relationship models of FDC under uniaxial tension and uniaxial compression are established with the Weibull distribution and spring damage element model by considering the damage factors such as the initial damage of concrete,the damage caused by elevated temperature and the damage healing under crack closure.Through the proposed method,four mechanical features of FDC are explained by theoretical derivation rather than test data fitting.The theoretical derivation results are compared with test data and the proposed method proves feasible in explaining the failure mechanism of FDC.