Eventos Anais de eventos
MecSol 2017
6th International Symposium on Solid Mechanics
TOPOLOGY OPTIMIZATION FOR THE MAXIMIZATION OF FREQUENCY SEPARATION MARGIN
Submission Author:
Heitor Nigro Lopes , SP , Brazil
Co-Authors:
Renato Pavanello, Jarir Mahfoud
Presenter: Heitor Nigro Lopes
doi://10.26678/ABCM.MecSol2017.MSL17-0145
Abstract
To avoid resonance problems in vibrating mechanical structures, it is desired to maximize the separation margin between natural frequencies in the operating frequency range. For this reason, optimization methods can be used to identify geometries that maximize the difference between two consecutive natural frequencies. In this work, a topology optimization method was used to maximize a given natural frequency gap and was tested on a two-dimensional linear elastic beam simply supported at each end. The algorithm implemented was BESO (Bidirectional Evolutionary Structural Optimization). As the evolutionary method progresses, some eigenvalues might approach the one being maximized, and the mode shift problem can emerge and disturb the convergence of the optimization algorithm. For this reason, a method based on multi-objective optimization is implemented and tested to control the mode shift problem. The multi-objective strategy used is based on the weighted sum method, where additional frequencies are added to the objective function. Since most studies show this problem often results in periodic topologies, a periodic constraint was implemented to test this behavior. Therefore, a strategy is proposed by combining these constraints and the method to control mode shift. Although this restraint did not produce topologies whose gap was larger, it allowed the removal of more elements, and thus, reducing environmental impact and its total weight.
Keywords
natural frequencies, frequency gaps, periodic structures, BESO, natural frequencies, frequency gaps, periodic structures, BESO
