Optimum design of a periodic pipe filter using waves and finite elements

Adding periodicities in structures leads to wavemodes interaction, which generates pass- and stop-bands. The aim of this paper is to optimise the wavemodes interaction for designing a vibro-acoustic pipe filter. The pipe is filled with fluid, and the heavy fluid loading effects are taken into account. Concentrated masses are attached periodically to obtain elastic and acoustic stop-bands in desired ranges of frequencies. This substantially reduces vibrations and noise transmission from sources having harmonics which fall in the tailored stop-bands. Dispersion curves and wavemodes are predicted using a Wave Finite Element approach. Numerical examples are presented and an optimization algorithm is applied to design a compact spiral shaped pipe filter suitable for industrial and domestic applications.