Metamaterial application to reduce noise transmission through glass

There are a number of ways to reduce noise transmission through automotive glass.  These methods are reviewed, and noise reduction results of a method involving a metamaterial attached to the glass edge will be discussed in the most detail.  This metamaterial is developed using topology optimization to provide a broadband beam or panel flexural wave absorber which is effective at a wide range of incidence angles.  Transmission loss measurements comparing laminated glass, tempered glass and tempered glass plus metamaterial show the acoustic TL performance at -20C, +20C and +40C of 0.3 m x 0.3 m flat panels.  Further work will include TL evaluation of metamaterial-treated glass in a fully trimmed automotive door assembly and on-road measurements to capture the noise reduction performance for both acoustic and turbulent sources.