NONLINEAR DYNAMICS OF STRUCTURES ASSEMBLED BY BOLTED JOINTS

The nonlinear transfer behaviour of an assembled structure such as a l arge lightweight space structure is caused by the nonlinear influence of structural connections. Bolted or riveted joints are the primary so urce of damping compared to material damping, if no special damping tr eatment is added to the structure. Simulation of this damping amount i s very important in the design phase of a structure. Several well know n lumped parameter joint models used in the past to describe the dynam ic transfer behaviour of isolated joints by Coulomb friction elements are capable of describing global states of slip and stick only. The pr esent paper investigates the influence of joints by a mixed experiment al and numerical strategy. A detailed Finite Element model is establis hed to provide understanding of different slip-stick mechanisms in the contact area. An advanced lumped parameter model is developed and ide ntified by experimental investigations for an isolated bolted joint. T his model is implemented in a Finite Element program for calculating t he dynamic response of assembled structures incorporating the influenc e of micro-and macroslip of several bolted joints.