The eigenvalue calculation can be used to identify critical operating conditions in the gearbox as early as the design phase. Eigenvalues are calculated from the masses and the linearized stiffnesses at the operating point in the system. The resulting natural frequencies are compared with the occurring excitation frequencies, and the user is then provided with a Campbell diagram for each gear stage and an animation of the eigenmodes in the 3d model.
Various types of gears such as spur and bevel gears as well as planetary gearings can be considered in the eigenvalue calculation. The dynamic mesh stiffness of cylindrical gears can even be automatically determined. Alternatively, if measurement results are available, the mesh stiffness can also be directly specified. The results of the calculation are the natural frequencies and eigenmodes of the entire gearbox. The energy content of the various modes is analyzed in a post-processing step.
The vibration modes are divided into the following categories: rotational, lateral, axial or mixed.
The critical operating points are evaluated in the Campbell diagram, which displays the eigenfrequencies and the gear mesh frequencies as well as the shaft orders. If they intersect within a user-specified speed range, this is a potential critical operating point. The torsional rotation of gears is also checked in the eigenmode. Only gears that do not oscillate in phase need to be examined more closely.