The modelling of the dynamic behaviour of three-dimensional model of
two-stage gear system is formulated for general helical gears location. The
excitation is induced by the periodic variation of the mesh stiffnesses.
This case describes the real working of the gearings. First, the modal
analysis of the system is treated. Then, the calculation of the dynamic
response is performed by a step-by-step time integration method (Newmark
method). Finally, two types of manufacturing defects on the gears are
introduced in the model: eccentricity and profile defect. An analysis of the
effects of these defects on the gear system dynamic behaviour is then
treated.