Keywords: FRF modelling, frequency response function modelling, substructuring, hybrid modelling, engine mounting, NVH, vehicle noise, noise path analysis, NPA, vehicle vibration, harshness response, mount tuning, mounting set, pick-up trucks
Optimisation of engine mounting systems using experimental FRF vehicle model
Engine and body mount systems play a crucial role in vehicles' comfort. Engine mounts protect the engine from excessive movement and forces due to low frequency road and high frequency engine excitations. On the other hand, body mounts protect the cabin from vibration forces exerted by the body. Normally, a complete set of mounts is conceived at early stages of design, subsequently the set is tuned in the refinement stage to improve the vehicle's noise, vibration, and harshness (NVH) response. Currently, noise path analysis (NPA) is used for mount tuning. This method is helpful, but it is based mostly on trial and error, and it does not lead to an optimum mounting set. In this work, a new technique is implemented to simplify vehicles' mount optimisation. This technique employs substructuring synthesis and standard NVH testing to obtain frequency response function (FRF) model of a vehicle. The model is linked to several optimisation routines to predict the optimum set of mounts for a desired objective function. For verification and evaluation, the method is applied to tuning the mounting set of a pick-up truck. Experimental measurements showed good correlation with optimised response.