High strain rate properties of material: Design and development of a test equipment and methodology

Abstract

Ballistic test equipment has been designed, constructed and commissioned for the firing of cylindrical projectiles at speeds up to 1000 m/s at small cylindrical/disc shaped test specimens placed upon a rigid anvil. Compressed air was used to propel the projectile whose speed before impact was measured using a laser-beam interruption device. An IMACON high speed camera was used to continuously record the deformation-time history of the specimen and these records were then used to obtain force, strain, stress and strain rate histories during the entire deformation process thus eliminating the need to obtain measured force-time history. The stress-strain curves over large strain were obtained from tests on specimens which where statically pre-strained to different levels. The effects of strain rate history and material inertia were found to be negligible, but the effect of friction was found to be significant and appropriate corrections were introduced.