The importance of R-DoF in blocked force descriptions of mechatronic components English Free Members only

  • Category Technical paper
  • Related event International Congress : NVH Comfort - 13-14 October 2021
  • Edition SIA
  • Date 11/02/2021
  • Author E. PASMA & M. HAÜßLER - VIBES Technology | J. FREUND, O.WESTPHAL & T. VOEHRINGER - ZF Friedrichshafen
  • Language English
  • Type PDF file (403.69 Ko)
    (Downloadable immediately on receipt of online payment)
  • Number of pages 8
  • Code R-2021-00-02
  • Fee Free

Component Transfer Path analysis (TPA) is a popular method for understanding and improving the NVH behaviour of automobiles. Before performing a component TPA, the engineer needs to think about the right modelling of the source's interface with the receiver. For practical reasons, the vibration transfer from the source to the receiver in each connection point is often modelled with three translational forces. Mechanically this corresponds to a ball joint connection, which cannot transfer moments.

The goal here is to compare different complexities of interface descriptions on an industrial example of an electromagnetic roll control in a passenger car. Another question for each TPA, is the degree of sensor over-determination in the matrix inverse. In this paper, three different variants of interface degrees of freedom and over-determination on each connection point are compared with each other.

These interface descriptions are compared in terms of an on-board validation, an evaluation of the recently proposed interface completeness criterion and by evaluating the transferability of the identified blocked forces to a modified vehicle design. It was found that the over-determination of the matrix inverse should be used in any case, to avoid spurious noise artefacts in the results. For best quality TPA results at higher frequencies, it was found necessary to include rotational moments in the interface description.