3D-DIC Analysis of a Metal Specimen Following an Impact Compression Test by the Hopkinson Bar Method

Introduction

Understanding the properties of materials is important in designing products. For this reason, there are various testing standards such as tensile testing, compression testing, and bend testing. Regarding transport aircraft, the possibility of sustaining impact loads must be taken into account, meaning that in order to accurately understand the properties of a material, impact properties must be grasped in addition to static properties. In particular, impact testing is necessary since the stress- strain characteristics of a material may differ between when it is subjected to a static load and when it is subjected to an impact load. The Hopkinson bar method is one method for impact testing. Proposed by Bertram Hopkinson, this method deforms a specimen by impact. A striker bar is fired against an input bar by a bar launcher, transmitting a compressive elastic wave through the input bar to apply a sudden force to the specimen which is contacting the input bar. In this study, an impact compression test was conducted on an aluminum alloy specimen by the Hopkinson bar method. The strain distribution on the surface of the specimen was visualized by recording the test with two HPV-X2 high-speed video cameras (hereinafter referred to as HPV-X2) and performing 3D digital image correlation (DIC) analysis.

March 23, 2018 GMT