P10.01: Comparative numerical buckling analysis: Of compressed carbon and stainless steel members at elevated temperatures

Abstract

Although all metals lose strength and stiffness when they are exposed to fire, the reduction of mechanical properties considerably varies between different metals. In contrast to carbon steel, austenitic stainless steel has better response at elevated temperatures due to relatively high content of alloying elements. The type of metallurgical microstructure crucially affected on material response and global behaviour of structural elements under fire conditions. Despite the fact that carbon steel and stainless steel have different constitutive patterns, EN 1993-1-2 states that resistance of structural elements made from these materials should be checked using the same fire design procedure. This paper presents numerical analysis of buckling resistance of compressed members exposed to fire, without fire protection. Finite element analysis is conducted using the ABAQUS software. The study points out the structural performance of columns made of stainless steel cold-formed hollow section and hot-rolled I-section in grade 1.4301 and identical columns from carbon steel grade S235 at high temperatures. Sensitivity to initial imperfections is also assessed. The thermal and mechanical properties of carbon and stainless steel are taken from EN 1993-1-2. Development of temperature into the columns in fire condition is obtained from standard fire curve, according to ISO834. The numerical predictions of buckling response are compared with results of design procedure according to Eurocodes EN 1991-1-2 and EN 1993-1-2. The aim of this paper is estimation of acceptability and accuracy level of the mentioned design guidelines in the treatment of buckling phenomena of stainless and carbon steel structural elements at elevated temperatures.