| 摘要 |
PURPOSE:To conduct the interference of a reflecting sound and attenuation in hollow sections effectively by forming a large number of pyramidal noise- suppressing projections to a tabular member while shaping the hollow sections into the projections and communication opening sections formed to each pyramidal surface and the hollow sections. CONSTITUTION:A noise insulation board for the outdoors in composed basically of a tabular member 1 and a plurality of noise-suppressing projections 2 projected from one surface of the tabular member. The noise-suppressing projection 2 has a pyramidal body, and an opening section 3 is formed to respective side surface of a pyramid, and a spherical hollow section 4 is shaped at the central section of the pyramidal body. The opening section 3 and the hollow section 4 are communicated. Accordingly, a radiated sound is muffled effectively by interference of each pyramidal surface and reflection interference and attenuation by the hollow sections. |
