Comparison of the reception plate method and the inverse force method for assessing the power of a dummy vibratory source

Multiple vibratory sources are integrated in the aircraft. The vibrational power of these sources is injected to the receiving structure through their connections points resulting in annoying acoustic levels in the cabin. This noise, referred to as structure borne noise, could be mitigated if vibrating systems, receiving structures and interfaces between them are well designed. Methods, such as Reception Plate Method (RPM), Inverse Force Method (IFM) or Component-Based Transfer Path Analysis (CB-TPA) have been developed to specify proper design guidelines related to noise mitigation during the design phase. This work focuses on the RPM and IFM, which allow for measuring the power from a vibratory source into a reception plate. Previous works, based on a round-robin evaluation, have shown that the RPM is very sensitive to the experimental test setup. The main errors come from the plate loss factor measurement and spatially-averaged plate velocity, which contribute directly into the power computation. In this work, a similar experimental setup has been developed. The experimental loss factor is obtained with the impulse response decay method and several automatic dB-decays are considered. The number of accelerometers and their positions are also investigated for assessing the spatially-averaged plate velocity. Both analyses allow for determining the RPM power with minimum-maximum deviation curves. The RPM results are compared with the IFM considering one and three translational degrees of freedom using a custom-made dummy source with a controlled tonal behavior varying from low (100 Hz) to high (1200 Hz) frequencies.