Transfer Path Analysis of Planetary Gear with Mechanical Power Recirculation

Planetary gears can transmit higher power density levels because they use multiple power paths formed by each planet branches. In order to study the propagation of vibration between components of planetary gear test bench with mechanical power recirculation, an approach to the classical transfer path analysis (TPA) method is used to improve vibration control of planetary gear test bench. This approach termed Global Transmissibility Direct Transmissibility (GTDT) avoids the drawbacks of the classical TPA which are decoupling of the active part in the measurements of the Frequency Response Functions (FRFs) of source-receiver paths and the difficult measurement of the operational forces. The Global Transmissibility Direct Transmissibility (GTDT) is two steps method: the first step is the measurements of transmissibility which requires no disassembly tests and the second step is the measurement of the operational responses which is easier than measurement of the operational forces. In fact, tri-axial accelerometers are mounted in each component of the back-to-back planetary gear test bench and the transfer functions (frequency response functions, FRFs) are measured using hammer impact test in order to measure the global transmissibilities. Then, the direct transmissibilities are computed from the global transmissibilities. Finally, reconstructed operation responses are shown in the partial path contribution (PPC) plots to compare the vibration level of each component and to know its contribution in the transfer of vibration.