An improved model for dynamic analysis of a double-helical gear reduction unit by hybrid user-defined elements: Experimental and numerical validation

This paper introduces an improved model generated by hybrid user-defined element method (HUELM) for dynamic analysis of a double-helical gear reduction unit. Based on theories of structural dynamics and system dynamics, the model consists of four developed elements to respectively simulate the gear pair, bearings, flexible shafts and the housing. A closed-loop test rig is constructed to validate the model: an encoder-based method is applied to measure vibration acceleration of the gear pair, and accelerometer-based measurement systems are employed to obtain the dynamic responses of the housing. Furthermore, two additional models by the finite element method (FEM) and the lumped mass method (LMM) are constructed for numerical comparison to illustrate the HUELM's substantial advantages. Compared with the LMM, the HUELM is of capacity to investigate the interaction among the subsystems; moreover, it is more efficient than the FEM primarily because of the integrated tooth contact analysis method and loaded tooth contact analysis method. It is demonstrated that the predictions by the HUELM match well with the experimental data in terms of meshing frequencies and vibration responses. It is also concluded from the numerical comparison that the HUELM is appropriate for dynamic analysis, particularly of large complex transmission equipment.