Advancement in Vehicle Development Using the Auto Transfer Path Analysis

This paper presents the most recent advancement in the vehicle development process using the one-step or auto Transfer Path Analysis (TPA) in conjunction with the superelement, component mode synthesis, and automated multi-level substructuring techniques. The goal is to identify the possible ways of energy transfer from the various sources of excitation through numerous interfaces to given target locations. The full vehicle model, consists of superelements, has been validated with the detailed system model for all loadcases. The forces/loads can be from rotating components, powertrain, transfer case, chain drives, pumps, prop-shaft, differential, tire-wheel unbalance, road input, etc., and the receiver can be at driver/passenger ears, steering column/wheel, seats, etc. The traditional TPA involves two solver runs, and can be fairly complex to setup in order to ensure that the results from the two runs are consistent with subcases properly labeled as input to the TPA utility. However, auto TPA allows necessary data needed for the TPA analysis to be requested in a single frequency response analysis run. The TPA breaks down the total response to partial contributions from interface points under operation loads. Partial contributions to total response are then computed by multiplying transfer function with the force transmitted through each interface location. By comparing the results of two-step TPA with auto TPA, the effectiveness and efficiency of the auto TPA have been demonstrated for three load cases: a) powertrain excitation for cruising acceleration to engine torque (A/T) and noise to engine torque (P/T), b) propshaft imbalance, and c) rough road excitation, which is based on the power spectral density (PSD) function.