COBEM99

S21 Vibrações e Análise Modal

Title:

COMPLEX MODES SELECTION CRITERIA APPLIED TO THE GENERALIZED MODAL SYNTHESIS METHOD - PART I : NUMERICAL SIMULATION

Summary :

THIS WORK PRESENTS A GENERALIZED METHOD OF MODAL SYNTHESIS APPLIED TO NON CONSERVATIVE SYSTEMS USING RESIDUAL FLEXIBILITY MODAL SUPERSETS. ALTHOUGH THIS METHOD IS USED MORE FREQUENTLY FOR EXPERIMENTAL ANALYSIS, IT CAN BE USED IN A ANALYTICAL APPROACH. A COMPLEX MODES OF ELIMINATION CRITERION IS PROPOSED IN ORDER TO AVOID THE USER INFLUENCE BY AUTOMATING THE SYNTHESIS PROCESS. IN THE MODAL SYNTHESIS METHODS, THE QUANTITATIVE AND QUALITATIVE INDICATION OF SUBSTRUCTURE MODES THAT ARE INSIDE THE ANALYSIS RANGE IS VERY IMPORTANT TO THE IDENTIFICATION PROCESS. SINCE THE PROCESS IS MADE ARBITRARILY BY THE USER, SOME MODES OF A SUBSTRUCTURE THAT HAVE HIGH SENSITIVITY TO FINAL SYNTHESIS CONVERGENCE MAY BE NOT SELECTED. THE CRITERION IS DEFINED USING A QUALITY INDEX THAT IS CALCULATED BY A CROSS WEIGHING AMONG THE MODES OF CONNECTED SUBSTRUCTURES. THE EUCLIDEAN NORM IS USED TO OBTAIN A INITIAL WEIGHT TO INDIVIDUAL MODES OF SUBSTRUCTURES, WHICH ARE USED IN THE CROSS WEIGHTING. THE SYNTHESIS OF SUBSTRUCTURES IS MADE USING A OPTIMIZED PROCESS OF GLOBAL REASSEMBLING. A DISCRETE MODEL OF SIX DEGREES OF FREEDOM IS USED TO VALIDATE THE METHOD PROPOSED AND THE ELIMINATION CRITERION. KEYWORDS: MODAL SYNTHESIS, MODAL SUPERSET, RESIDUAL FLEXIBILITY, IDENTIFICATION, EXPERIMENTALANALYSIS.

Author :

Araújo, Cleudmar Amaral de
Kurka, Paulo Roberto G.

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