| Summary: | 碩士 === 元智大學 === 機械工程學系 === 92 === ABSTRACT
Generally, structures include various joints, which have great influence on the static and dynamic characteristics of the structures. The joint is also the most difficult part of the structure to model for analysis purpose. The previous joint identification method proposed by our laboratory is a direct method and the damping effects are not included in the joint model used. If inaccuracy occurs in the final results, no measure is taken to correct the discrepancy between the experimental and analytical results. This research aims at proposing an effective updating method for identification of joint parameters. An iterative improvement algorithm is used to refine the identified results, where the results from the direct method are used as the initial values of the iteration.
The new identification method of structural joint parameters, utilizing substructural synthesis method and iterative improvement method, was developed to identify the stiffness and damping of the bolted joints of a structure. The merit of the iterative improvement method is that the identified parameters are successively refined to achieve more accurate results. The iteration method includes initial values, iteration definitions, and termination conditions. The major work is in the development of the algorithm of the iteration definitions.
An automatic identification procedure integrating the Matlab programs and ANSYS software is employed to save manual operation time, promote the efficiency of the identification processes, and obtain accurate identified results.
In additional to joint stiffness, internal damping of the structure and joint damping are identified, which increase the accuracy of the modeling. The coupled effects of the joint stiffness and damping are also discussed. The advantage of the proposed identification method is that the joint parameters are identified for each frequency.
Finally, a cantilever beam bolted at one of its ends is tested to validate the proposed identification method.
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