Constitutive Modeling of High-Strength Steel Designed for Ballistic Protection

Constitutive behaviour of a high-strength nanostructured bainitic steel NANOS-BA® was investigated in the article. A few types of mechanical tests under varying strain rates were carried out to determine the values of constants of Johnson-Cook flow and fracture models for the analysed material. In quasi-static conditions (8×10-3 s-1) the material samples were subjected to uniaxial tension and compression tests. In a high strain rates conditions (2,7×103 s-1) the Taylor impact test was carried out. On the basis of the data obtained from mechanical tests the constitutive model of the NANOS-BA® steel was built. It was then validated to determine the extent and degree of compliance between the numerical and experimental observations. The examples of combined numerical-experimental analyses of protective structures containing investigated material were shown. Small differences between the both types of results testifies that determined constants of Johnson-Cook equation may properly reproduce actual behaviour of the material, and the numerical model allows the preliminary evaluation of the effectiveness of armours containing layers of analysed grade of steel