A structure dynamic model updating method for random vibration fatigue life prediction

In order to overcome the low precision of vibration fatigue life analysis of complex engineering structures, a structural dynamic model updating method for random vibration fatigue life prediction was established. In this model updating method, the stiffness and modal damping of key parts such as structural connection are extracted as model modification parameters. The approximate model of modified parameters and target is established to replace the finite element model of complex structure based on the Kriging method. The actual natural frequency and random vibration response spectrum of the structure are taken as the modified objectives to design the optimization experiment and find the optimal model parameters. And based on the amplitude probability density method of random vibration fatigue life analysis, the vibration fatigue life of complex structure is obtained. Finally, the method is verified by structural dynamic experiment. The result shows that the method can effectively modify the parameters of dynamic finite element model for the prediction of structural vibration fatigue life, and improve the accuracy of structural random vibration fatigue life prediction.