The effect of high loading rate to tensile strength for mild steel by using Hopkinson Bar technique

Abstract

This paper presents the effect of high strain rate loading to tensile strength for mild steel by using Hopkinson bar technique. The behavior of material at high strain rates is important for application such as structural impact, automotive safety engineering and metalworking. In automotive industries, mild steel has been used as material in some of component. Due to dynamic condition occurrence during vehicle crash it is important to analyze the strength of component. Split Hopkinson Pressure Bar (SPHB) is the most common method for determining material properties at high strain rates, it consist of two long slender bar that sandwich a short cylindrical specimen between them. A striker bar impacts the incident bar, producing in it elastic wave pulse that travels through the incident bar and then reaches specimen. Upon arrival at the specimen, the wave partially reflects back towards the impact end and the remainder of the wave transmits through the specimen into the second bar. By capturing the wave pulse at the Hopkinson Bar apparatus a stress-strain relationship on the specimen can be calculated. It is found that the tensile strength on the stress-strain diagram increase significantly compared to a static test