Dynamic test and constitutive model of 225 MPa low yield point steel material and its energy absorption ability

Based on Low Yield Point (LYP) steel's attractive features, e.g. relative lower yielding strength, better plasticity performance than traditional structural steel material, the feasibility of utilizing LYP steel material for absorbing blast and impact/shock energy through its plastic deformation is discussed in this paper. Selected 225 MPa class LYP steels made by Chinese An Gang Corp., abbreviated as AQ225, are tested via quasi-static and split Hopkinson pressure bar (SHPB) experiments, respectively. Then, Johnson-Cook dynamic constitutive model is developed through a comprehensive thorough processing of raw test data. Moreover, the reliability of achieved model and its corresponding parameters are discussed. Finally, the dynamic response of a square plate structure made of LYP steel as well as other different types of steel materials, e.g. high-strength HQ600 and normal highstrength low alloy steel Q345, subject to explosive loading is studied through numerical simulations. As a result, the advantages of LYP steel for absorbing blast and impact energy through the accumulated plastic deformation are demonstrated, which provides the basis of utilizing such material for protective structures.