A Unified Rheological Model for Analysis of Steel Behaviour at High Temperature

Abstract

This paper presents the theoretical background for development of a unified rheological model (URM) for low-carbon steel which is sensitive to the temperature and strain-rate effects during fire exposure. The proposed URM consists of a serial connection of two Kelvin-Voight (KV) rheological elements. Each KV element is used to simulate a particular material strain (stress-related and creep strain) in fireaffected steel. The first KV element is capable of taking into account strain-rategoverned change of yield strength and the second is sensitive to variation of heating rate. A verification of the proposed URM by using test data from transient coupon tests of steel Grade 275 is also presented.