Determination of crash-relevant material properties of stainless steel alloy and constitutive equations

Abstract
This work presents results of tensile testing of H400 stainless steel at different strain rates in the range 0.001/s-1000/s. This type of steel grade is a strong candidate for use in crash-absorbing automotive components due to a good balance between strength and ductility and excellent energy-absorption capacity. For that application an understanding of material behaviour at relevant strain rates is needed as well as constitutive equations suitable for use in analytic and numerical calculations. Mechanical properties were determined from tensile tests using flat sheet specimens and recurring to different test techniques: servo-hydraulic machine and a tensile-loading Hopkinson bar. The test results were used to compare different mechanical properties of the tested steel and a Dual-Phase steel grade. The results were used to compare and validate constitutive equations intended to provide a mathematical description of strain rate dependence. The Cowper-Symonds equation was examined.