COBEM99

S21 Vibrações e Análise Modal

Title:

UPDATING METHOD OF FITTING MODELS

Summary :

THE NECESSITY OF OBTAINING NUMERICAL MODELS THAT REPRESENT THE BEHAVIOR OF STRUCTURES ADEQUATELY HAVE MOTIVATED MANY RESEARCHES IN THE LAST TWO DECADES ABOUT METHODS OF FITTING MODELS. THE AIM OF THIS WORK IS TO PRESENT A TECHNIQUE OF FITTING MODELS THROUGH AN UPDATING METHOD. THE METHOD IS BASED ON THE ERROR MINIMIZATION BETWEEN FREQUENCY RESPONSE FUNCTION (FRF) NUMERICALLY AND EXPERIMENTALLY OBTAINED. THIS MINIMIZATION IS PERFORMED BY THE OPTIMIZATION TECHNIQUE “GOAL PROGRAMMING” COUPLED TO A FINITE ELEMENT PROGRAM. THE VARIABLES OF THE PROBLEM ARE THE DATA OF THE NUMERICAL MODEL AND THE DAMPING RATES OF THE ANALYZED MODE SHAPES, WHICH ARE KEPT, BETWEEN THE USER ESTABLISHED LIMITS. ON THIS WAY, FITTING OF THE NUMERICAL MODEL TAKE INTO ACCOUNT THE STRUCTURE GEOMETRY AND CAN BE CONTROLLED BETWEEN THE IMPOSED RESTRICTIONS TO THE VARIABLES, SUCH AS TO KEEP THE FINAL RESULT INSIDE THE ACCEPTABLE LIMITS TO THIS VARIABLES. A BASIC PRINCIPLE OF THIS TECHNIQUE IS THE UPDATING BETWEEN THE SYSTEM AND THE USER. THUS, THE OPTIMIZATION PROCESS DOESN’T TAKE TO A UNIQUE SOLUTION, BECAUSE TAKES INTO ACCOUNT THE USER EXPERIENCE ON SOLVING SIMILAR PROBLEMS. KEY-WORDS: FITTING OF MODELS, STRUCTURAL DETECTION, OPTIMIZATION.

Author :

Magluta, Carlos 0
Oliveira, Renata Silva de
Roitman, Ney 0

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