Dear xansys users, I am working in a project in which I have to make an impact on a graphite epoxy composite plate with a spherical ball and study the failure characteristics and import contact reaction Vs time graph for different boundary conditions.I am doing this analysis in Ansys workbench with ACP pre ,explicit dynamics and ACP post module.First I gave the material properties of orthotropic composite material and isotropic ball material and modelled the geometry.Then I did the meshing and did all the necessary steps in ACP pre module. I have taken shell element for composite.So while doing the analysis in explicit dynamics module I am facing one error that ''required equation of state is not assigned to the shell element" .First I have tried giving equation of state as bulk modulus and shear modulus but while selecting this in 'Engineering Data' section orthotropic properties are getting checked.Means the software is not considering the orthotropic properties.So I am getting wrong results. Please help. With regards Ansuman Sahoo. IIT GUWAHATI. Get Outlook for Android<https://aka.ms/ghei36>