Experimental and numerical study of the behavior of HSLA and DP cold‐formed high‐strength steels at elevated temperature.

Due to the rapid development in steel manufacture, a new generation of structural cold‐formed advanced high strength steels have been developed. However, due to the variations in chemical composition, their material properties have not been fully understood, which includes the mechanical performance when exposed to fire. Therefore, a series of steady‐state elevated temperature tests were conducted on dual phase (DP) and high‐strength low alloy (HSLA) steels with different thicknesses and nominal yield strengths up to 700 MPa to investigate their performance in the range of 20°C to 700 °C. This paper presents detailed results and discussion of the experimental study. A two‐stage plus linear model based on Ramberg‐Osgood equation is proposed to depict the stress‐strain relationship for the materials at elevated temperature. The prediction of the new material model and common existing material models to represent the material properties of steel at elevated temperatures are compared to the test data and current code predictions. [ABSTRACT FROM AUTHOR]