高温条件下混凝土墙体的非线性分析研究

NONLINEAR ANALYSIS OF CONCRETE WALL AT HIGH TEMPERATURE

论文建立了一个弹塑性-损伤耦合本构模型用于数值模拟高温下混凝土的真实破坏过程.导出了一个利用Newton-Raphson迭代的一般的直接应力返回映射算法.同时求解应力向量和塑性、损伤的内状态变量.并推导了用于化学-热-湿-力学耦合分析的全局守恒方程Newton-Raphson迭代过程的一致性切线模量矩阵.建议了一个用于弹塑性-损伤耦合分析的两级求解过程.给出的数值例题结果显示了所提出的算法和公式的正确性,表明了所发展的弹塑性-损伤耦合本构模型在模拟高温下混凝土墙体中复杂破坏过程的能力.

A coupled elastoplastic-damage constitutive model for the numerical simulation of realistic failure in concretes at high temperature is developed in this paper.A general direct stress return mapping algorithm,using Newton-Raphson iteration,is derived.The stress vector and scalar internal state variables quantifying the incremental plasticity and damage are updated simultaneously.The consistent tangent modulus matrices for coupled chemo-thermo-hygro-mechanical analysis are formulated for use in the global Newton iterative procedure.A solution procedure with two hierarchical phases for the coupled elastoplastic-damage analysis is proposed.Numerical examples are given to demonstrate the validity of the presented algorithm and formulations,illustrate the capability of the proposed constitutive model in reproducing coupled chemo-thermo-hygro-mechanical behavior in concrete wall subjected to fire and thermal radiation.