ACOUSTIC INSULATION FABRICATION AND TECHNIQUES

摘要

Intense acoustic noise and vibration are unavoidable and undesirable by-products generated fromrnthe launching of a spacecraft. The generated noise during the firing of a rockets engine transfersrninto the vehicle, avionics, and launch pad in the form of airborne acoustics. Therefore, arnsuccessful mission requires detailed consideration of complex sound and vibration interaction ofrnvibro-acoustics effects.rnThe noise and vibration caused by spacecraft rocket engines on launch pads is extremely intensern(approximately 180dB). The noise at launch during the two-minute liftoff and transonic climbrnphase causes hostile, noisy and vibratory environment not only for the spacecraft itself but alsornfor the delicate electronics and payload packages aboard.rnAcoustic blankets can effectively suppress these intense noise levels. This is done using openrncell foam or batting of various thicknesses. The foam is enclosed in a cover that can be made of arnvariety of materials, including Teflon carbon coated fiberglass or aluminized plastic film. Inrnorder to relieve pressure created by changing altitude, breathing patches made from a metallicrnmesh must be installed. The size and shape of these patches can be different depend on design ofrnthe blanket.rnThe fabrication of acoustic blanket in general and specific issues on methods of fabrication isrnwhat we would like to discuss in this paper along with the latest techniques of how to preventrnissues associated with acoustic blankets.