Ballistic response of natural rubber sheet against the hemispherical projectile: An experimental and numerical approach

In this paper ballistic behavior of natural rubber sheets is analyzed against the projectile impact through experimentation as well as numerical simulations. The size of natural rubber sheets was considered as 150 mm × 150 mm with varying thickness 5, 6, 8, and 10 mm. The rubber sheets were impacted against the 10 mm diameter hemispherical projectile having weight of 17 gm and length of 26 mm respectively. The ballistic tests were carried out with in the velocity range of 36–73 m/s. For the ballistic impact experiment on the natural rubber sheet, a pneumatic gas gun was used whereas numerical simulations were carried out through explicit ANSYS/ LS-DYNA. To simulate the damage behavior of the rubber material against such a complex loading condition, the Mooney-Rivlin damage model was considered. To obtain the material parameter value of the Mooney-Rivlin model for natural rubber sheets, uniaxial tensile test was performed. Moreover, the first and second invariant-based different strain energy density functions were used to define the hyperelastic behavior of this rubber sheet. The analytical results were compared with FEM hyperelastic model and prepared a single set of material parameters for the damage model which deal with the ballistic response against the projectile. The numerical model was validated against the experimental results in terms of residual velocity, energy absorption, ballistic limit, and damage pattern and the results were found to be in good correlation.