Damping Model Updating Based On Modal Tests For Changing Structural Parameters

The finite element model updating technology is a key technology in structural dynamics modeling and simulation.Based on the ICMCM method with damping,the ICMCM method with additional mass and changing boundary conditions is proposed.The selection of the location was studied.The details are as follows:The ICMCM method with damping is developed from the CMCM method.This model updating method is characterized by updating for each element matrix of the finite element model.If there are many element matrices,there may be a problem that the number of unknowns is too large and the number of equations is insufficient when correcting.In order to solve this problem,an additional mass damped ICMCM method and a damped ICMCM method for changing boundary conditions are proposed.A new structure is obtained by adding concentrated mass or changing boundary conditions to the original structure,and finding a connection between the new structure and the original structure.The modified equation obtained by the new structure is superimposed on the original equation.The number of equations increases and the unknown number does not change,which can solve the statically indeterminate problem.If two vibration modes are similar,the correction equations obtained are similar,which is not conducive to the equation superposition solution.Therefore,a position selection method for adding concentrated mass and changing the boundary conditions are proposed.This method is used to eliminate the bad position of adding mass and changing the boundary condition.In order to verify the method proposed in this paper,a damping structure is taken as an example.After the updating,the frequency error is reduced and the contact ratio of frequency response function curve between test and simulation is improved.The value of the proposed model updating method in practical engineering is verified.