Research On Sound Insulation Performance And Test Method Of Building Glass

Requirements of sound insulation of building is rising with worse noise problems. Since glass is the weakness of building insulation, it is urgent to evaluate acoustical glazing systematically and find new test methods to accelerate application and manufacture of acoustical glass.After being analyzed with FEM, impedance tube method was introduced to measure sound transmission loss(STL) of glass. It is shown that STL of single glass is increased by about 6.1dB as the thickness of glass is doubled. The result accords with mass law and proves the effectiveness of impedance tube method. Experiments on laminated glass verify the conclusion that interlayer can increase STL only at resonance and coincidence frequency. Impedance tube method for big panel is also used. STL differences between two methods is shown at resonance frequency. For some acoustical material which has low Young's modulus, STL curve is quite similar at most frequency. In this case, impedance tube method can be replaced by impedance tube method for big panel to avoid complexity of sampling.A device used for measuring sound insulation performance was set up based on lock-in amplifier. The device can be used in common laboratory, which can cut the cost of test sharply. The test result of single glass is similar to the result obtained in sound insulation room. Lock-in amplifier is also used with impedance tube to extend the measurement of high insulation material.Sound insulation mechanism of vacuum glazing was investigated based on the results obtained from experiments, documents and SEA calculations. It is shown that sound insulation of vacuum glazing is increased with the falling of pressure in cavity until a limit was reached, which is determined by sound bridge, such as pillars and edge connection. So sound insulation of vacuum glazing is controlled by both sound bridge and pressure in cavity. Only when transmission of vacuum layer is dominative, sound insulation of vacuum glazing could be increased by pressure in cavity. Experiments show that sound insulation didn't change with pressure, which is as same as the conclusion of some documents. That means sound transmission from sound bridge is much greater than that from vacuum layer. It's also found from SEA calculation that small cavity between two panels is responsible for the high insulation performance of vacuum glazing. Some insulation dips, which appear at sound insulation curve, would move with pressure in the cavity. The dip frequency is deemed as resonance frequency of glass under the mounting of pillars. Sound insulation dip frequency of vacuum glazing is controlled by both pillars and pressure in cavity together.Comprehensive summary of insulation performance of typical acoustical glass was made. Noise map was drew which concludes both intensity and spectrum. With these data, it is convenient to find appropriate glass for different noise situation.