Experimental Modal Analysis On Correlation Vibration Source

Firstly, a systematic study of lots of paper is made, modal analysis method that accord to frequency response function is introduced. Method based on component analysis (peak value pick-up) and global orthogonal polynomial subsection fitting to obtain system damping ratio, natural frequency and modal shapes is especially described. On the basis of above, identification method on vibration source correlation of multi-input and multi-output system is studied.(1)Equation is deduced when input is complete correlation, frequency response function has not solution (order of numerator of polynomial need not be defined). We can directly use superposition principle of linear system to obtain response without solving frequency response function. In the process of solving, poles are obtained from recurrent formula, modal vector are obtained from superposition formula not residuary. Decoupled equation is derived when vibration source is part correlation, severely coupling appears in the process of input and output then frequency response function cannot directly get according to method mentioned above, decoupling is first problem. Corresponding MATLAB code is also complied.(2)In order to verify derivation equation and corresponding code effectiveness, four-point exciting experiment of plate structure is set up by applying vibration table, then part correlation data is obtained. Use body method to analysis and get modal parameters of plate. In order to verify accuracy of identification result, Finite Element Method (for example ANSYS) is used to simulate and calculate. Through comparison experimental identification result with ANSYS simulation result, effectiveness of method in this body to obtain modal parameters is verified, then identification accuracy is more perfect.(3)In order to prove multi-point exciting experiment good, we employ traditional ergography(hammering method) to make experiment, peak value pick-up method to modal identification, and compare identification result by hammering method with vibration table experiment. The result revel that vibration table experiment can obtain larger energy and more adequately excite...