A coupled MBS-FEM approach for computing the dynamic overloads in thin web gears

In aerospace gearboxes, very thin gears are used in order to reduce the weight of the system. The low stiff of such gears introduces additional natural frequencies in the working range of the gearbox, determining noise and sometimes fatigue failures. Traditional techniques are not so useful for computing the dynamic overloads that this kind of gears generates, so a coupled MBS-FEM analysis is requested. In the present paper, the capabilities of gears analysis with the coupled MBS-FEM analysis are investigated with respect to gears with very thin geometry. Main results of the present paper are the demonstration of the validity of coupled MBS-FEM analysis in gear dynamic analysis and that, in such particular very flexible solution, also the web and the rim stiffnesses are fundamental in defining the gear dynamics and the load exchanged by the gears each other and with the other gearbox components.