Design of a Multiwaves Vibration Filtering

In vibroacoustic, bandgap effects related to periodic and/or locally resonant architectural materials can lead to new types of structural vibration filters. This communication concerns periodic pipes used in industrial context. Such pipes are seen, as architectural structural waveguides in which flexural, torsional, and longitudinal waves can propagate. To control the propagation of these vibrations and reduce their possible noise disturbance, Bragg or resonant band effects can be obtained by architecting the axial variations of the cross-section. As a result, a waveguide can be tuned to create stop bands with bandwidths large enough to make them interesting for industrial applications. For this purpose, dispersion relations are derived and analyzed based on the Floquet method and numerical Finite Element simulations. In many practical cases, all kinds of waves generally coexist due to the inevitable structural couplings. Therefore, the optimization of the geometric and mechanical characteristics of the structure must be realized to attenuate several (at least two) types of waves at the same time. The response of optimized architecture pipes of finite size is simulated using the finite element method in order to illustrate the potential filter effect for practical applications.