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TPA and NVH Prognosis - Application to Mercedes Benz Car Development of New Hybrid Methods Coupling Digital Simulation with Prototype Testing Results
Abstract:
Digital NVH development has become a common tool for any acoustic engineer. Vehicles in their early development stages are nowadays mainly described and validated as digital models. However there still remain needs for improvement in the domains of acoustic and vibration prediction, as instance: refining models, addressing intricate systems, and CAE resistant phenomena. In a background of increasing modularity and process transfers, hybrid methods coupling with testing results, have shown a great potential for improving the quality of NVH prognosis and development quality.
Mercedes-Benz passenger car division has developed, tested and introduced a new engineering tool, based on the classical TPA applications coupled with hybrid simulation techniques. This toolbox is used to enhance the prognoses of acoustic interior noise and vibration comfort.
The actual NVH development process for engines and vehicles is described with main quality gates and objectives, showing when established or new methods come into use. In order to reach an effective operational level of the toolbox, it was necessary to standardize and automate thoroughly the whole acquisition and processing chain. This meant defining a standard for data acquisition and structure, setting procedures for signal processing and analysis, and developing new measurement methods.
The following examples are described: Automated measurement procedure for the reciprocal determination of transfer functions. Procedure for direct evaluation of input dynamical forces and airborne noise measurements acquired at engine test benches. In order to demonstrate the potential of mentioned methods, an application to the NVH development of an engine and the achieved end results are presented, illustrating the systematically project maturity evaluation, the virtual integration of engine and powertrain in some existing vehicle types, as well as the interactive virtual testing of different power train types, variants are other possibilities.