Characterization and modelling of the mechanical behaviour of metal rings: Application to a brass bullet jacket

Abstract

Tubular or pipe structures are commonly found in various engineering applications, such as offshore pipelines, parts in the nuclear and automotive industries. Standard mechanical testing methods like compression tests on cylindrical samples or tensile tests on dog-bone samples are often out of questions due to the geometry restraints. Carrying out standardized mechanical characterization on ring-shaped samples could thus be a solution. The goal of this paper is to successfully conduct mechanical characterization of copper alloy rings, which are extracted directly from the jackets of small calibre ammunition. Firstly, an experimental protocol has been established to investigate their mechanical behaviour in the quasi-static regime. The strain rate and temperature sensitivities have also been evaluated through the same experimental process. Furthermore, a Johnson-Cook constitutive material model has been identified using an inverse analysis of lateral compressive experiments. This identification is based upon the ABAQUS/Standard ® finite element software coupled with the optimization software LS-OPT®.As a result, a low anisotropic material behaviour is demonstrated. Finite element simulations using identified parameters are in accordance with the experimental measurements from compressive tests in axial direction.

Keywords

• Metal rings
• Material characterization
• Inverse methodology
• Calibration of Johnson-cook model