Abstract: A mass-spring-damper model for the structure of bolt-flange is put forward, with viscous damping and coulomb damping. Simulation is carried out withan exponentially decayed pressure pulse acting on the flange. In thesimulation the effect of the pre-stress in bolts, the bolt numbers, thedamping between flange and bolts is studied. The pre-stress in bolts andthe bolt numbers have a great effect on the peak of bolt deformation.The damping has not much effect in this respect.