A MODEL UPDATING METHOD FOR PLATE ELEMENTS USING PARTICLE SWARM OPTIMIZATION (PSO), MODELING THE BOUNDARY FLEXIBILITY, INCLUDING UNCERTAINTIES ON MATERIAL AND DIMENSIONAL PROPERTIES

Abstract

IT IS WELL KNOWN THAT IN A REAL ENGINEERING SITUATION, THE FIXTURES ARE NOT IDEAL STIFF, SO, NUMERICAL SIMULATIONS USING THIS FIXTURES ARE UNLIKELY TO PRESENT RESULTS CONSISTENT WITH THE EXPERIMENTAL ONES. THE PRESENT PAPER INTENDS TO DESCRIBE A METHODOLOGY OF MODEL UPDATING BY INSERTING TRANSLATIONAL AND ROTATIONAL SPRING IN ORDER TO BETTER REPRESENT THE REAL CLAMPING. FOR THIS PURPOSE, THE PSO STOCHASTIC OPTIMIZATION METHOD WILL BE USED TO DETERMINE THE SPRING STIFFNESS IN AN ITERATIVE WAY. IN ADDITION, UNCERTAINTIES ABOUT THE MATERIAL PROPERTIES, LIKE DENSITY AND YOUNG’S MODULUS, AND WORKPIECE DIMENSIONS, WILL BE ALSO TAKING INTO ACCOUNT ON THE OPTIMIZATION ALGORITHM. KNOWING THE EXPERIMENTAL NATURAL FRE-QUENCIES AND THE GEOMETRY OF THE STUDIED PART, THE ALGORITHM AUTOMATICALLY UPDATES THE MODEL, APPROXIMATING AS CLOSE AS POSSI-BLE THE NATURAL FREQUENCIES OBTAINED THROUGH THE NUMERICAL MODEL WITH THE MEASURED EXPERIMENTALLY ONES. IN ADDITION, THE MODAL SHAPES OF THE MODEL UPDATED SIMULATION WILL BE COMPARED WITH THE EXPERIMENTAL DATA AND WITH A RIGID BOUNDARY SIMULATION. RESULTS DEMONSTRATED THAT THE METHODOLOGY PROPOSED WAS EFFI-CIENT TO REPRESENT THE FIXTURING FLEXIBILITY, BOTH NATURAL FREQUENCIES AND MODE SHAPES FOUND WERE CLOSER TO THE REAL DYNAMIC SYSTEM.