板状試験片の衝撃引張試験法の検討

Abstract

This study is concerned with the split Hopkinson bar method for tension test of strip specimens. The split Hopkinson bar method (SHB) has been used for impact tests such as compression and shearing, and is currently modified for tension test. It is demanded that the impact tensile behaviour of high-tensile strength steel plates is made clear in the design of light-weight and high stiffness automotive parts for weight reduction in materials. However, the method of impact tension test using the SHB has not been established because the testing conditions such as specimen geometry and fastening are quite different from them in compression test. In this paper, the characteristics of the SHB method for tension test are examined using by some experiments and numerical simulations. Particularly the appearance of initial peak in stress-strain curves like an increase of yield point is discussed from the viewpoint of the specimen geometry and the attachment of a specimen and stress bars with screws. It is found that the fastening method affects strongly the responses of stress waves measured on an output bar and then causes the virtual peak in the initial portions of stress-strain diagram.