轴心受压H形截面不锈钢柱抗火性能分析

基于国产奥氏体S30408不锈钢材料,针对轴心受压H形截面不锈钢柱,采用高温稳态分析和瞬态分析两种方法对其抗火性能开展了有限元数值模拟分析,揭示了不锈钢柱高温下受力性能与破坏模式。通过高温稳态分析,给出了不同温度下不锈钢柱的荷载-位移曲线及极限承载力-温度曲线;通过高温瞬态分析,研究了特定火灾升温模式下不锈钢柱表面温度的变化规律,给出了不同荷载比下不锈钢柱的临界温度;并将两种方法的计算结果与《欧洲规范》(EN1993-1-2)的计算结果进行对比分析。在此基础上,分别采用高温稳态分析和瞬态分析方法,对不锈钢柱的抗火性能开展了参数化分析,着重考察了构件初始缺陷、荷载比、截面尺寸以及长细比对高温下极限承载力和临界温度的影响。研究结果表明:构件的长细比和截面尺寸为轴心受压H形截面不锈钢柱高温极限承载力的主要影响因素,荷载比为不锈钢柱临界温度的关键因素,初始缺陷对不锈钢柱的抗火性能影响不明显。

FIRE RESISTANCE PERFORMANCE ANALYSIS OF H-SECTION STAINLESS STEEL COLUMN UNDER AXIAL COMPRESSION

Based on Austenitic stainless steel material S30408, numerical simulation analysis is performed on H-section stainless steel column in fire under axial compression by steady state and transient state analysis method. Mechanical performance and failure mode of stainless steel column are revealed in this paper. Load-displacement curves and ultimate bearing capacity-temperature curves are plotted through steady state analysis method. The temperature development of column and critical temperature of column under specific load are obtained through transient state analysis. The analysis results of the two methods are compared with Eurocode (EN1993-1-2). Parametric analysis is performed by steady state analysis and transient state analysis to study the fire resistance performance of stainless steel column. The influences of the initial imperfection, load ratio, section size and slenderness ratio on the ultimate bearing capacity at elevated temperature and the critical temperatures are investigated. The results show that the slenderness ratio and section size are the main influence factors on the ultimate bearing capacity of stainless steel column at elevated temperature, and the load ratio is the key factor of critical temperature of column, while the effect of initial imperfection on the fire resistance performance of column is not obvious.