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Comparison of numerical and experimental study of armour system based on alumina and silicon carbide ceramics

Chabera P., Boczkowska A., Morka A., Kędzierski P., Niezgoda T., Oziębło A., Witek A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2015

Vol. 63, nr 2

363--367

The main goal of this numerical and experimental study of composite armour systems was to investigate their ballistic behaviour. Numerical simulations were employed to determine the initial dimensions of panel layers before the actual ballistic test. In order to achieve this aim, multivariate computations with different thicknesses of panel layers were conducted. Numerical calculations were performed with the finite element method in the LS-DYNA software, which is a commonly used tool for solving problems associated with shock wave propagation, blasts and impacts. An axisymmetric model was built in order to ensure sufficient discretization. Results of a simulation study allowed thicknesses of layers ensuring assumed level of protection to be determined. According to the simulation results two armour configurations with different ceramics have been fabricated. The composite armour systems consisted of the front layer made of Al2O3 or SiC ceramic and high strength steel as the backing material. The ballistic performance of the proposed protective structures were tested with the use of 7.62 mm Armour Piercing (AP) projectile. A comparison of impact resistance of two defence systems with different ceramic has been carried out. Application of silicon carbide ceramic improved ballistic performance, as evidenced by smaller deformations of the second layer. In addition, one of armour systems was complemented with an intermediate ceramic-elastomer layer. A ceramic-elastomer component was obtained using pressure infiltration of gradient porous ceramic by elastomer. Upon ballistic impact, the ceramic body dissipated kinetic energy of the projectile. The residual energy was absorbed by the intermediate composite layer. It was found, that application of composite plates as a support of a ceramic body provided a decrease of the bullet penetration depth.

Finite element modelling of the residual stresses in the ceramic-elastomer composites

Boczkowska A., Konopka K., Babski K., Krzesiński G., Kurzydłowski K. J.

Materials Science Poland

2005

Vol. 23, No. 2

529--534

Ceramic-elastomer composites are obtained by the infiltration of porous ceramics by an elastomer prior to the curing reaction at elevated temperatures. Because the elastomer and the ceramic have different expansion coefficients thermal stresses are generated during cooling to ambient temperature. In addition the elastomer contracts as it transforms from a mixture of the substrates in the liquid state to the solid state polymer with a covalently bonded network structure. These two phenomena result in the development of residual stresses in the composite. Residual stresses are of significant concern because they can cause damage in the form of cracks in the ceramic and delamination between the ceramic and the elastomer. They can also have an effect on the mechanical properties of the composite. The aim was to model in 3D space the residual stresses in the composites with two different interpenetrating phases. The Finite Element Method (FEM) was used to calculate the stresses.