Comparison between Experiments and FEM Simulation of High Velocity Tensile Test Methods to Clarify Test Method's Influence of High Strength Steel

In order to examine the compatibility of improvement of crashworthiness with weight-saving of automobiles by using high strength steel, a combination analysis of Finite Element Method and Dynamic Mechanical Properties has been established. The material properties used in this analysis have been measured by “one bar method” high velocity tensile tests, which can examine the deformation behaviour of materials at an actual crash speed range (∼55km/h). As for the accuracy of this system, comparison between experiments and FEM simulation both of this test machine and other high-velocity-tensile-test machines have clarified the feature of one bar method and the metallurgical features of high velocity deformation.

It was confirmed that the stress-strain curve measured by the one bar method agreed with that measured by the modified Split Hopkinson pressure bar method. It was also confirmed by FEM analysis that appropriate stress-strain curve to deform at high strain rate could be identified by using the one bar method because of no influence of the dispersion of stress wave. By FEM simulation of one bar method, the initial peak of the stress-strain curve could be analyzed.