Large-strain quasi-static compression materials tests in support of penetration modeling research.

摘要

Target penetration by projectiles typically generates large strains, at least locally. Hence, accurate analytic modeling of penetration demands that constitutive models be calibrated using large strain material test data. Tensile test data is limited by specimen necking (the Considere criterion), restricting attainable strains. Linear extrapolation of tensile data to target strains can seriously overestimate the material flow stress, resulting in erroneously stiff analytical predictions. That is, other tests which can attain larger strains often reveal a continually decreasing tangent modulus at large strains. We report quasistatic room temperature compression tests approaching true strains of (var epsilon) = (minus)1. A few tensile tests are included to illustrate the previous point. Materials tested are 7075-T651, 5083-H131, and 6061-T651 aluminum alloys, 4340 steel and X21-C tungsten alloy. 7 refs., 6 figs.