高温下混凝土的本构模拟及破坏分析

针对已建立的高温下混凝土中化学-热-水力-力学耦合过程分析的分级数学模型,发展了混凝土的化学-热-水力-力学(CTHM)耦合本构模型。在已有的Willam-Warnke弹塑性屈服准则基础上发展了考虑脱水和脱盐引起的材料损伤及化学塑性软化、塑性应变硬化/软化和吸力硬化的广义Willam-Warnke本构模型,模拟高温下混凝土的材料非线性行为。为保证全局守恒方程的Newton迭代过程的二阶收敛率,导出了非线性化学-热-水力-力学(CTHM)耦合本构模型的一致性切线模量矩阵。数值结果显示了本文所发展的化学-热-水力-力学(CTHM)耦合本构模型在模拟高温下混凝土中复杂破坏过程的能力和有效性。

Constitutive modeling of concrete at high temperature and failure analysis

A coupled chemo-thermo-hydro-mechanical(CTHM) constitutive model for concretes is developed for the hierarchical mathematical model in the coupled chemo-thermo-hydro-mechanical analysis of concretes at high temperature.Based on the existing elasto-plastic Willam-Warnke yield criterion,a generalized Willam-Warnke yield criterion with consideration of material damage and chemo-plastic softening due to the dehydration and the desalinization,plastic strain hardening/softening and suction hardening is developed to simulate the non-linear material behavior of concretes at high temperature.Consistent tangent modulus matrices for coupled non-linear chemothermo-hydro-mechanical constitutive modeling are formulated to ensure the second order convergence rate for the Newton iterative procedure of the global balance equations.The numerical results demonstrate the capability and the validity of the proposed coupled CTHM constitutive model in simulating the complex failure processes in concretes at high temperature.