Manatee software offers powerful tools to identify the root cause of e-NVH issues. One of these tools is the Load Case contribution plot which allows to quickly visualize the linear contribution of each load case to the overall noise or vibration and which is expressed in percentage.
For instance, the first graph shows that the Sound Power Level in dBA at 3000 rpm is driven at ~48% by loadcase r=-2, stator, radial (forces applied on the stator in radial direction with a wavenumber r=-2) and at ~47% by loadcase r=-2, stator, circ. (forces applied on the stator in circumferential direction with a wavenumber r=-2).
Note that in dB/dBA, a 50% linear contribution corresponds to a 3dB contribution.
The contribution plot can be used by mechanical and NVH engineers to easily identify the root cause of the e-NVH issue, whether it is air-borne or structure-borne, radial or circumferential.
An automatic split of internal/external and radial/circumferential load cases is also available through the “Split contributions” button to understand whether the e-NVH issue is air-borne or structure-borne, radial or circumferential along the speed. In particular, the effect of torque ripple and unbalanced magnetic pull on stator and rotor can be separated.