Structural Sound Insulation Testing Technology Research

Strict experimental conditions and expensive special acoustics apparatus are demanded in traditional structure sound insulation tests. So reduce the effect of the testing environment and apparatus to the testing results, improve the precision and frequency range of the testing, and realize the testing condition simplified but result are exact are important to the noise controlling engineering.The theoretic analysis and experiment validation of structure sound insulation testing in common environment were studied in this thesis. The sound insulation formula of the compound panel was deduced by applying the Wave Analysis Approach. The sound insulation properties of compound panel that made from different materials could be forecasted by applying this formula, and can supply theoretical conducting for the compound panel structure design. The theoretical and approach to create digital impulse signal using the computer were researched in this thesis, and experiment validation were also done. The good agreement of the theoretical and experimental results showed that: the digital impulse signal had the virtues of sufficient energy, easy for design, good repetition, and suitable for wide band testing. Influences of the testing system characteristic on input signal were analyzed using the DSP theory. The effects were equalized using the least squares filter and the deconvolution equalization methods, and then the problem of response deficient was solved. The influence of diffraction and reflection at the margin of testing sample was analyzed. The testing accuracy was increased by separating the availability signal from all signals. Finally, traditional free field impulse method was improved, and a new sound insulation testing method in non-anechoic chamber was proposed. This testing method could get away from the dependence on the special acoustic apparatus, the influence of testing system characteristic on the testing result is reduced, the broadband testing of anticipant frequency range can be realized, the condition of testing sample is lowered. Compared with the traditional testing, not only the testing efficiency and repeatability were improved, the testing accuracy was also increased remarkably by using the method in common environment. This testing method is suitable for practical application.