抄録
Sound absorber panels with using fibrous sound absorbing materials are widely applied to suppress noise from railways or roads. In these cases fibrous sound materials are often wrapped with thin film to protect from rainwater or not to be scattered and lost. But performance of sound absorption in high frequency region is decreased because of that film. So we developed the sound absorber panel composed of a micro-perforated thin aluminum plate, two sheets of micro-perforated aluminum foil and air spaces. The diameter of holes, perforation ratio, thickness of plate or foil and depth of air space are optimized by calculation. The experimental value of the performance of sound absorbing agreed well with one by calculation. The performance of sound absorbing by micro perforated sheets was found to be better than one by fibrous material in high frequency region. The attenuated noise level was measured to test the performance of this panel set along the railway. We found that this panel had much more sound absorption than fibrous material covered with thin film.
