Model Validation And Application Using Radial Axial Tchebichef Moment Function Instructural Dynamics

Model validation, including verification, correlation and model updating, is the process of enabling the discrepancy between the prediction result of FE model and the test data within the acceptable limits. Correlation and model updating are two important key step.With the development of modern non-contact vibration test technology, such as the laser Doppler velocity, the full field experiment vibration data, which reveals the limitation of traditional correlation and model updating method, can be obtained. Besides, the traditional correlation analysis method can't describe the double modes of symmetrical structure. So the moments function method, which is wide used in the image processing areo, is proposed for correlation analysis and model updating. But the previous researchs on moment function are mostly about 2D moment function, which results in problems when appled in common engeneeing 3D stuctrual. So a new 3D moment function method, which can be directly used in 3D structural without resulting in problems, is proposed in the article.Firstly, the RAT moment function is proposed, and the orthogonality of the polynomials is proved, and the reconstruction formula is derived. Then, the feasibility of image description method based on RAT moment function is verified, taking a simulated cylinder case as an example, and the description ability of different moment functions including 2D Radial Tchebichef moment function and 2D Tchebichef moment function is compared. In addition, the de-noising mothod based on RAT moment function is studied. Finally, the dynamic model validation method based on RAT moment function is mainly studied. RAT moments are applied to the correlation analysis and model updating. Taking a front case of a whole engine experimental prototype as an example, the vibration modal test and FE model simulation are carried out to obtain the test data and simulation data for the correlation and modal updating. Results shows that the new correlation method can successfully identify the influences of double-modes in the structures, and accurately find the paring modes, so this method can overcome the disadvantages of MAC. And the new model updating method makes the results tend to converge and avoids divergence or oscillation, the frequency deviation between the test and FE model is reduced from-6.2% to 1.8% after model updating, so this case verifies the correctness and feasibility of the proposed method. This is the development and innovation of traditional dynamic model updating method.