Evaluation of stop bands in periodic and semi-periodic structures by experimental and numerical approaches

Adding periodicity in structures leads to wavemode interaction, which generates pass- and stop-bands. Stop-bands are related to the periodic nature of the structure. Thus structural periodicity can be shaped in order to design vibro-acoustic filters to reduce vibration and noise transmission. The aim of this paper is to investigate numerically and experimentally stop-bands in periodic one-dimensional structures. Two methods for predicting stop-bands are described: the first applies to infinite structures using a wave approach; the second deals with the evaluation of a structural transmission loss coefficient. Numerical examples concerning periodic beams are presented. Results are discussed and validated experimentally. Very good agreement between the numerical and experimental models in terms of stop-bands is showed.