A DYNAMIC SUBSTRUCTURE TECHNIQUE FOR THE TRANSIENT DYNAMICS OF NON-HOMOGENEOUS FLEXIBLE BARS WITH IMPACT

The fixed-interface mode synthesis dynamic substructure technique was applied to study the impact problems of the non-homogeneous flexible bars with variable cross-section longitudinally struck at its free end by a moving rigid mass. The transient dynamics equations were derived and expressed in mode coordinates. The two methods to determine the initial conditions of impact were discussed. The dynamic substructure technique can calculate the complicated impact force history successfully, the transient wave propagation along the bars and the impact transient response. Numerical examples show that the calculation results are convergence and the precision of the numerical solution is high enough compared with the analytical solution when the number of element exceeds to 180 and only two fixed-interface normal modes are selected. When the more elements and higher order normal mode are chosen, this method may be applied to the study of the transient dynamic of the complicate flexible structure.