On the application of shunted piezoceramics for increasing acoustic transmission loss in structures

The application of electrically shunted piezoceramic materials (PZTs) for i ncreasing transmission loss is studied. A test setup in an SAE J1400 facili ty is used to analyze the sound transmission loss due to a test plate with shunted PZTs, and to compare the results with an undamped plate and a plate with constrained-layer damping materials. The test results indicate that s hunted PZTs can increase sound transmission loss by approximately 6 dB for a pure tone input at 162 Hz, and 7 dB for a broad band input of 10-10000 Hz . The test results further show that, compared to the constrained layer dam ping materials that are commonly used in the automotive industry, PZTs prov ide a substantially higher sound transmission loss-to-weight ratio. This pa per will present the test setup in an SAE J1400 facility, the installation of the PZTs on a test plate, and the tuning procedure that is used for the shunt circuits. It also provides a detailed analysis of the results of soun d transmission tests for three different test plates, namely an undamped pl ate, a plate with constrained layer damping, and a plate with electrically shunted PZTs. (C) 2001 Academic Press.