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采用ANSYS有限元分析软件对门式钢刚架结构受火力学反应全过程进行数值模拟,得到门式钢刚架破坏时的临界温度和最不利截面位置,并从结构力学基本理论出发,验证ANSYS数值模拟结果的正确性。研究结果表明,大空间建筑火灾中,影响门式钢刚架结构抗火承载力的控制截面主要是梁柱节点处的梁端截面和梁跨中截面,而且烟气温度场非均匀性将影响结构控制截面的位置,从而影响结构临界温度的变化规律;随着荷载比的减小,临界温度呈升高的趋势;门式钢刚架结构受火破坏模式表明单榀门式钢刚架结构在考虑檩条提供的平面外约束条件下,由于结构冗余度较少,当构件截面发生破坏后,整体结构随即丧失承载力。研究结果可供门式钢刚架结构的抗火设计参考。
The ANSYS finite element analysis software is used to simulate the whole course of steel frame structure subjected to fire and the critical temperature and the most unfavorable cross section position are obtained. According to the basic theory of structural mechanics, the ANSYS value The correctness of the simulation results. The results show that the control cross-sections that affect the fire-resistant capacity of portal steel frame structures in large-scale building fires are mainly the beam end cross-section and mid-span cross-section, and the non-uniformity of temperature field of flue gas will affect The position of the structure control cross-section, thus affecting the change law of the critical temperature of the structure. With the decrease of the load ratio, the critical temperature tends to increase. The failure mode of the steel portal frame by fire shows that the single- Considering the out-of-plane constraints provided by the purlin, the overall structure immediately loses its bearing capacity after the failure of the cross-section of the structure due to less structural redundancy. The research results can be used as fire resistant design reference for portal steel frame structure.