混凝土中化学-热-湿-力耦合过程的数值方法

提出了一个火灾下混凝土中化学-热-湿-力耦合过程分析的两级数学模型. 混凝 土模型化为充满两种非混溶孔隙流体的非饱和变形多孔多相介质. 数学模型基于控制干空 气、湿份及基质溶解物的质量守恒、混凝土介质混合体的动量守恒和焓(能量)守恒的耦合 偏微分方程组. 模型中特别考虑到了高温下的脱盐过程. 构造了一个用于数值模拟 化学-热-湿-力耦合行为的有限元求解过程的混合弱形式. 并且针对其中具有非自伴随算子特性的 双曲线控制方程的空间离散进行了特殊考虑. 数值结果例题显示所发展的数学模型和数值方 法在重现火灾条件下的混凝土中化学-热-湿-力耦合行为的有效性.

Mathematical model and numerical method for simulation of coupled chemo-thermo-hydro-mechanical process in concrete subjected to fire

A hierachical mathematical model for analyses of coupled chemo-thermo-hydro-mechanical behavior in concretes subjected to fire is presented. The concretes are modeled as unsaturated deforming reactive porous media filled with two immiscible pore fluids. The mathematical model consists of a set of coupled, partial differential equations governing the mass balance of the dry air, the mass balance of the water species, the mass balance of the matrix components dissolved in the liquid phases, the enthalpy (energy) balance and momentum balance of the whole medium mixture. The thermo-induced desalinization process is particularly integrated into the model. A mixed weak form for the finite element solution procedure is formulated for the numerical simulation of chemo-thermo-hydro-mechanical behaviors. Special considerations are given to spatial discretization of the hyperbolic equation with non self-adjoint operator nature. Numerical results demonstrate the performance and the effectiveness of the proposed model and its numerical procedure in reproducing the coupled chemo-thermo-hydro-mechanical behavior in concretes subjected to fire.