INVESTIGATIONS INTO THE EFFECTIVE USE OF STRUCTURAL MODIFICATION

摘要

Structural Modification is growing in importance in the modal analysis arena, particularly in troubleshooting applications. Unfortunately, since it is a relatively new technique, there is a lack of general understanding and practical experience with its application. This paper addresses these issues by evaluating the accuracy of structural modification relative to errors and deficiencies of typical modal data. A finite element model of a simple structure is constructed and solved to obtain its modal properties. The modal model with its FEM parent is analogous to the results of a modal test of a structure and a perfectly correlated analytical model. Structural modifications are applied to the modal model and the results are compared to the same modifications applied to the original finite element model. The studies evaluate the effects of important potential errors with structural modification including: modal truncation, the lack of rotational degrees of freedom in the modal model, and the effect of inaccuracies in mode shape coefficients.