Abstract
The present study proposes an optimization method of laminated CFRP plates with variable thickness. The objective function is the fundamental frequency calculated by the originally developed finite element code with a 4-node rectangular (ACM) element, and design variable are placements of elements with reinforcement layer. A simple genetic algorithm method is employed with elitist tactics as an optimizer. The obtained plates with optimum placement of reinforcements and optimum fiber orientation angle result in the highest fundamental frequency among representative models. Then, based on the optimization results, the test specimens are fabricated by using hand lay-up and vacuum curing technique with pattern paper which keeps thicknesses difference clearly. Measured frequencies and modes shapes agree well with the calculated results and the fabricated optimum plate also indicates the higher fundamental frequency than other representative ones. Furthermore, the optimum variable thickness plate yields higher frequency compared with the homogenous thickness plate due to its small mass. This observation demonstrates an advantage of the variables thickness plate in terms of vibration characteristics.
