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Method

The acoustic evaluation of the virtual component is carried out in a modal frequency response analysis based on Finite Element method. Using the frequency domain has the advantage that transient start-up effects do not interfere with the frequency response solution. Additionally the modal approach leads to very efficient computations.

For the generation of the load data tables in frequency domain the engineer can use the pre-processing capabilities of MNOISE. Especially the interface to MSC Adams request file format for reading complex load data series simplifies the data transfer to the FE solver. Supported software for pre- and post-processing:

  • MSC Nastran
  • ABAQUS

Additionally an ASCII interface allows the load data generation from arbitrary source.
After finishing the FE simulations MNOISE can be used for evaluation of acoustic quantities in the near field of the analyzed component. For this purpose one can define specific surface points and areas of interest. For these surfaces one can evaluate

  • Mean square of surface normal velocities (called mobility) over frequency for each surface
  • Mean noise levels (near field sound pressure in dB or dB(A)) over frequency for each surface
  • Acoustic power (in dB or dB(A)) over frequency for each surface
  • Acoustic power - or noise level - distribution of frequency bands
  • Campbell diagrams of acoustic power or noise levels for each surface
  • Campbell diagrams of individual points (structure borne noise evaluation)