Numerical and experimental investigations on the acoustic performances of membraned Helmholtz resonators embedded in a porous matrix

International audienceAcoustic performances of two concepts based on the integration of an elastic membrane in the front wall of a cavity and Helmholtz resonator embedded in a melamine matrix are studied. Membranes are made of acrylic material, this latter is first characterized with a uniaxial test in order to extract the mechanical properties needed to model the membrane. Analytical, numerical and experimental investigations are performed so as to determine the acoustical potential of the proposed systems in terms of absorption and transmission loss. The contribution to the sound absorption can be positive or negative at the resonator resonances, an analytical model is proposed to highlight the physical phenomena related to these effects. In addition, a multiphysics numerical model combining the acoustic-mechanical interaction has been developed and validated by comparison with the experimental data measured using an impedance tube. The studied concepts could other significant enhancements of sound transmission loss properties in the low frequencies but also on acoustic absorption in specific frequency bands