The best alternative to test fields to assess blast effects on structures is numerical simulation. The best numerical model is the one that enhance the ratio accuracy / cost, indeed, an accurate simulation is useless if it came at an excessive cost in views of time or needed resources. In this study, a coupled solution, that overlooks the blast wave formation, is presented and compare with full simulation and experimental results from a shock tube. In a first part, the different ways of finding the blast wave at a certain distance from and explosive charge are compare, in a second part, the suitable ones is use in 3D software that deals with fluid and structure.