Topological indentation pattern design of plates for maximum frequency gap

The vibrational response of thin plates is improved by a new approach of indenting some portions along the normal direction so that the interval between two successive eigenfrequencies is enlarged while keeping their mass the same. Binary-coded genetic algorithm (GA) is used as the search algorithm. A stochastically-applied deterministic filter is developed like another genetic operator for GA to accelerate the convergence speed. The corresponding eigenfrequencies and their mode shapes are found by using finite element analysis. The results indicate significant improvement for the band-gap over no indentation designs and show the effectiveness of the new operator of GA.