Gearbox vibratory analysis using carrying, coupling and slave substructures

Abstract

Vibration analysis of complex structures is usually accomplished by analysing its finite element model. When the total number of degrees of freedom in the model is too large, we deal with large-scale eigenvalue problems. The classical approach for the solution of such problems consists in reducing the number of unknowns, allowing reducing the computational cost of eigensolver. Component mode synthesis or dynamic substructuring methods are appropriate tools for this reduction. In this paper, a novel approach in dynamic substructuring for numerical simulation of complex structures is presented and three type of substructure are considered. (1) Carrying substructure (plates and beams), (2) coupling substructure (organs joining carrying substructures), (3) slave substructure (elements connected to the carrying substructure). This approach is based on the use of the Craig-Bampton decomposition of the admissible displacement field. A numerical example is presented. A gearbox with elastic casing, two transmission shafts and one helical gear pair is analyzed and concepts for reduced noise and vibration are identified.