METHOD OF ESTIMATING PERPENDICULAR INCIDENCE/TRANSMISSION LOSS CHARACTERISTIC CURVE BY ACOUSTIC TUBE

摘要

PROBLEM TO BE SOLVED: To provide a method which enables a precise estimation of a perpendicular incidence/mass low-curve in a wide frequency range.;SOLUTION: Single-layer material having a uniform and homogeneous structure or various materials of laminated members thereof exhibit a mass-law curve having perpendicular incidence/transmission loss with a slope of 6 dB. The mass-law curve passes through a level position corresponding to the frequency of a mass control region of a transmission loss curve measured in the acoustic tube or the position in the vicinity thereof. When the measured transmission loss curve has two kinds of low-frequency and high-frequency regions, the mass-law curve passes through both the two kinds. Introduction of perpendicular incidence/transmission loss expression (1) including resonance enables a draw of a pseudo curve by performing curve fitting to a measurement curve, and the perpendicular incidence/mass-law curve can be precisely estimated in a wide frequency range.;COPYRIGHT: (C)2007,JPO&INPIT