Method optimization of optimum measurement point selection in experiential modal analysis

As an important basis of the validation of the finite element model, the result of experimental modal analysis is influenced by various aspects, one significant aspect is the measurement point selection. A new optimal measurement point selection method, namely effective independent-coefficient variance of modal kinetic energy (EI-CVMKE) method was proposed based on the effective independent (EI) method and the modal kinetic energy (MKE) method. Besides, a new criterion called the coefficient variance of modal kinetic energy (CVMKE) was presented. The obtained optimal measurement points using the new method were compared with those gained by EI method and MKE method. The advantage and disadvantage of those three methods were demonstrated by three evaluation criteria which are CVMKE, modal assurance criterion (MAC) and singular value decomposition ratio (SVD ratio). A computational simulation and a modal test on an aluminum alloy plate were carried out to demonstrate the feasibility of the optimal measurement point selection method. The result shows that EI-CVMKE method can not only make the truncated mode shapes as linearly as possible but also enable the measured MKE to maintain the maximum value. The new method is most feasible in the three methods.