冷弯薄壁钢短柱在均匀高温下的性能

Behavior of Cold-Formed Thin-Walled Steel Short Columns under Uniform High Temperatures

本篇文章对常温及均匀高温条件下的冷成型薄壁短槽钢的轴向强度进行了初步研究。对常温及均匀高温下的一系列卷边的或非卷边的槽钢进行了试验研究。应用一系列的设计方法和商业化的有限元软件ABAQUS( 1998)对试验进行了分析。本文中涉及的设计方法包括 :英国规范BS5 95 0 ( 1987)、欧洲规范Eurocode 3Part1.3 (CEN1996)和美国规范AISI( 1996) ,在有限元分析中 ,考虑了几何非线性和材料非线性。高温下钢材的应力 -应变曲线根据欧洲规范Eurocode 3Part 1.2(CEN1995 )和Qutinen ( 2 0 0 1)采用。在某些试验中发现扭转屈曲 ,为了扩展针对这种破坏模式的设计方法 ,在这些规范中引用了Yong和Hancock( 1992 )考虑扭转屈曲的方法。对设计规范BS5 95 0Part 5 ( 1987)、欧洲规范Eurocode 3Part 1.3(CEN1996)和美国规范AISI( 1996)中常温下薄壁柱的设计方法加以修改 ,来考虑钢材高温下的强度和刚度的变化。从试验结果、规范预期的结果和数值分析的比较可见 。

This paper presents the results of a preliminary investigation into the axial strength of cold-formed thin-walled short channel sections under ambient and uniform high temperature conditions. A series of ambient and high temperature tests were carried out on cold-formed lipped channels and unlipped channels. These tests have also been analyzed by using a variety of design methods and a commercial finite element program ABAQUS (1998). The design methods considered in this paper include the British standard BS5950 Part 5 (1987), the Eurocode 3 Part 1.3 (CEN 1996) and the American Specification AISI (1996). In the finite element analysis, both geometrical and material non-linearities are taken into account. The high temperature stress-strain relationships of steel are determined according to Eurocode 3, Part 1.2 (CEN 1995) and Qutinen (2001). In particular distortional buckling has been observed in many tests. To extend the capacity of the design methods to deal with this kind of failure mode, the method of Young and Hancock (1992) for calculating distortional buckling capacity is introduced in these codes. The ambient temperature design methods for thin-walled columns in BS5950 Part 5 (1987) , Eurocode 3 Part 1.3 (CEN 1996) and the AISI specification (1996) are modified to take into account the changes in the strength and stiffness of steel at elevated temperatures. From extensive comparisons between the test results, codes' predictions and numerical analyses, it may be concluded that by adopting the aforementioned modifications, the current code design methods can be easily modified to consider these advanced modes of behavior.