I am working on a project "vehicle ride dynamics using component mode synthesis." I would be making a matlab code to determine the vehicle body response due to road excitation signals. I will be modelling the tyre stiffnesses using springs, suspension with springs and dampers and vehicle body using plate of varying stiffnesses. I want to know that how a vehicle body can be approximately modelled with a plate of varying stiffnesses so that it reflects the real car body, as just assuming it as plate( of constant stiffness) will be too crude approximation. Also i woluld like to compare various CMS methods like free interface, fixed interface, hybrid interface on this system. If anybody has done any work in this field please provide some guidance.