A continuous dynamic constitutive model for normal- and high-strength structural steels

Abstract

The use of numerical models in the advanced analysis and design of steel structures, particularly under extreme loading conditions, is becoming increasingly widespread. A crucial component of such models is an accurate description of the material response. A systematic study into the dynamic constitutive modelling of structural steels is presented herein. The key features of the dynamic stress–strain characteristics of structural steels at various strain rates, i.e., test methods, material strength, strain-rate effect index and strain-rate effect models, are examined and discussed. Supplementary SHPB tests on both normal- and high-strength structural steels (Q235, Q355, Q460, and S960) under a wide range of strain rates up to 5000 s−1, filling gaps in existing datasets, are then carried out. A database of dynamic test results, containing 453 stress–strain curves, is systematically established and analyzed. Finally, a continuous dynamic constitutive model, capturing the dependency of both yield strength and strain rate, is proposed to predict the dynamic stress–strain response for structural steels, from normal- to high-strength material (235–960 MPa), and from static to high strain rate loading conditions (up to 5000 s−1).