A numerical model for NVH analysis of gearboxes employed on agricultural equipment

The aim of this paper is to describe a numerical vibro-acoustic methodology, experimentally assessed, for the estimation of the overall vibratory and acoustic level of a gearbox employed on agricultural equipment. The process is carried out in order to create the NVH digital twin of the real gearbox. The vibro-acoustic model is the combination of three sub-models: a lumped-parameter (LP) model, a structural finite-element (SFE) model and an acoustical finite-element (AFE) model. The LP model is used to obtain the reaction forces on the bearings during working conditions. Reaction forces are employed as an input for the further SFE dynamic model to evaluate the dynamic response of the gearbox’s case, which is the only meshed part. The dynamic response is exploited to set-up an AFE model which allows to estimate the noise generation in terms of overall acoustic pressure. The numerical simulation results are validated using experimental data acquired on a real gearbox. Testing activities have been carried out at Comer Industries facility in Reggiolo, where specimens and test benches have been set. Advantages and limitations of the model are reported.