ON THE APPLICATION OF SHUNTED PIEZOCERAMICS FOR INCREASING ACOUSTIC TRANSMISSION LOSS IN STRUCTURES

The application of electrically shunted piezoceramic materials (PZTs) for increasing transmission loss is studied. A test setup in an SAE J1400 facility 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 shunted 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 damping materials that are commonly used in the automotive industry, PZTs provide a substantially higher sound transmission loss-to-weight ratio. This paper 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 sound transmission tests for three different test plates, namely an undamped plate, a plate with constrained layer damping, and a plate with electrically shunted PZTs.