Effect of installation conditions on laboratory sound insulation measurement and an equivalent method for simply supported boundary

This paper investigated the effect of installation conditions on laboratory sound insulation measurement, and proposed an equivalent method for simply supported boundary. First, taking a typical thin plate as an example, an equivalent method for simply supported boundary of the thin plate in the sound insulation opening is studied. Second, through the measurement (in Opening #1) and simulation of vibration characteristics, the feasibility of equivalent simply supported boundary of thin plates with different materials and sizes is analysed. Then, based on modal test and the method of rational fraction polynomial analysis, the composition and main influencing factors of additional damping in the process of approximate simply supported boundary equivalence are further investigated. Finally, repeated measurements and verification are carried out in another Opening #2. The repeatability and reproducibility of sound insulation test results of the same aluminium plate in Opening #1 and Opening #2 are analysed. The results demonstrate that the approximate simply supported boundary method in the sound insulation measurement in this study is convenient and efficient. It is especially suitable for sound insulation tests of small, thin panels without a specific use.