Failure simulation of stratified panel under ballistic impact

"This paper presents an analysis of an isothermal model for an impact simulation in order to use the results for virtually optimizing the thickness of the panel for the same threat. The target has a stratified structure; the connection between layers is ""bonded"", with ""breakable"" detachment when there is exceeded a value for tensile stress and shear stress, introduced with the value of 90 MPa for tensile loading and 60 MPa for shear stress, these being characteristic values for the resin used for attaching the layers in the actual panel. Using Explicit Dynamics Ansys, it is possible to distinguish the stages of the impact process and how they depend on panel thickness. All bodies involved in impact are deformable, the bullet materials having a Johnson-Cook model and the layer being characterized. Even if the layer material model was simplified to a hardening isotropic bilinear model with data from the literature, the results were validated by the number of layers destroyed for the partially penetrated panels and by the size of the delamination on the back of the last layer. This simulation is useful for reducing the number of initial tests for evaluating the ballistic resistance."