Acoustics and vibrations team

Acoustics in ducts

This axis, through its two numer­i­cal and exper­i­men­tal com­po­nents, is a ref­er­ence of the team’s his­tor­i­cal com­pe­tence. It is still of great inter­est in the field of trans­port (aero­nau­tics, auto­mo­tive) and in the build­ing sec­tor (air con­di­tion­ing). Until now, our efforts have been focused on the guid­ed prop­a­ga­tion and radi­a­tion aspect. We have recent­ly extend­ed this axis to the gen­er­a­tion of noise and vibra­tions by the flow in the pres­ence of obstacles.

Materials and vibro-acoustics

Porous and struc­tured mate­ri­als are known for their sound-absorb­ing prop­er­ties, due to their high poros­i­ty and pore size of about a tenth of a mm. The research work focus­es on the one hand on the homogenised prop­er­ties requir­ing a descrip­tion of the microstruc­ture, and on the oth­er hand on the prop­er­ties of these mate­ri­als in a vibro-acoustic con­text, where their envi­ron­ment also stress­es their vis­co-elas­tic properties.

As far as the vibra­tions of com­plex struc­tures are con­cerned, the work focus­es on the devel­op­ment of spe­cif­ic meth­ods (semi-ana­lyt­i­cal and/or numer­i­cal) for the cal­cu­la­tion of trans­mis­sion through mul­ti­lay­er struc­tures of the elas­tic-porous material/viscoelastic type, but also on the vibro-acoustic radi­a­tion of the struc­tures, the gen­er­a­tion and vibro-acoustic radi­a­tion of trans­form­ers and elec­tri­cal coils, and final­ly on the non-lin­ear vibra­to­ry dynam­ics of mul­ti­lay­er met­al bellows.

Final­ly, the devel­op­ment of numer­i­cal meth­ods adapt­ed to medi­um and high fre­quen­cy cal­cu­la­tion is also part of the team’s con­cerns with the devel­op­ment of spe­cial finite ele­ments whose inter­po­la­tion func­tions are enriched by par­tic­u­lar solu­tions of the wave equa­tion (plane waves). Work is cur­rent­ly in progress on the devel­op­ment of the Par­ti­tion of Uni­ty Finite Ele­ment Method (PUFEM) for the sim­u­la­tion of three-dimen­sion­al acoustic fields in the pres­ence of absorbent materials.