Static mesh stiffness decomposition in hybrid metal-composite spur gears

The aim of this work is to analyse the static behaviour of innovative geared transmissions, made of steel and composite material, by decoupling the total meshing stiffness and accounting for the different influence of the gear teeth and the body. Firstly, the model of the transmission is created in a finite element (FE) environment by considering the macro-geometry of the gears and the material properties of the teeth and the composite web, made of triaxial braided plies. Static non-linear FE analyses are conducted to evaluate the static transmission error (STE) curve of the of the geared system, from which the total mesh stiffness is derived. The latter is then decomposed and ideally seen as a series of two springs, representing the teeth contribution as a function of the mesh cycle and the web behaviour. Thus, the stiffness contribution given by the teeth alone can be evaluated and replaced in the FE simulations with spring elements. The analysis and the comparison of the obtained results with the solution used by considering full bodies show the quality of the presented approach.