基于ABAQUS的火灾下钢筋混凝土结构精细化建模技术研究

Research on precise modeling technology of reinforced concrete structure under fire based on ABAQUS

基于通用有限元软件ABAQUS,对火灾下钢筋混凝土结构的温度场确定方法和高温下材料的本构进行了研究。结果表明:1)温度场分析,需试算并对比已有试验数据,反推得到对流传热系数和辐射率,从而确定截面的温度场;2)热力耦合分析,钢筋的本构可以选取强化关系,也可以选取理想弹塑性关系,混凝土的本构应当选取塑性损伤模型;3)建模过程中的边界条件、加载方式和网格疏密等因素对数值计算的收敛性和准确性有很大影响,需慎重考虑。

Based on general finite element software ABAQUS, the method of determining the temperature field of reinforced concrete structure under fire and the material constitutive under high temperature are studied. The results indicate that： （1） in temperature field analysis, compared with the existing experimental data, the multiple calculations are needed to obtain the convective heat transfer coefficient and the emissivity, so as to determine the temperature field of the section; （2）in thermo-mechanical coupling analysis, the strengthening relation can be applied to constitutive relationship of rebar, the ideal elastoplastic relation can be chosen as well, and the damage plastic model should be applied to constitutive model for concrete; （3）the boundary condition, loading mode and mesh density in modeling process have a great influence on the convergence and accuracy of numerical calculation, which need to be considered carefully.