Extensive Database of Damping and Sound Absorbing Materials
AAP has been collecting an extensive database of damping material and sound absorbing materials. Damping materials are tested using the ASTM E-756 standard. The data collected during the test yields to the damping ratio and loss factor in terms of temperature and frequency. Both thin layers of damping materials (in a constrained layer configuration) or thick layers (in a free layer configuration) have been cataloged so that they can be used in the modeling of a single layer or multilayer system.
Sound absorbing materials have been tested using the impedance tube method as well as the reverberation room method. Using the impedance tube method, it is possible to catalog the foam material properties such as tortuosity and porosity. These properties are then used to model different material thicknesses. Most common types of foams have been tested including different density and construction. Special type of foam materials for high flame resistance have been tested as well as the effect of different type of treatments for specialized applications.
The database of materials is continuously updated and used in the simulation tools at AAP’s disposal.
Special treatment of spaced absorbers is also catalogued so that the proper parameters can be quickly defined for the desired application.