A SIMPLE ESTIMATING METHOD OF CONSTITUTIVE EQUATION FOR STRUCTURAL STEEL AS A FUNCTION OF STRAIN RATE AND TEMPERATURE

In a previous paper, it was suggested that the constitutive equation for mild steel can be presented as a function of strain rate- temperature parameter (R). It was in good agreement with experimental data. However, many round bar tension tests need to be carried out to estimate constitutive equations for other structural steels. In this paper, a simple method to decide on the material constants for estimating a constitutive equation using the suggested method is investigated. In this method, the material constants can be easily decided if only the yield stress under quasi-static condition at room temperature is given. An attempt is made to estimate constitutive equations for cases of mild steel and HT-80 steel at various strain rates and temperatures. As a result, it is clear that constitutive equations for arbitrary steels can easily be obtained if only the yield stress under quasi-static condition at room temperature is given.