Learning Forum

[leo liu]

I want to use the Cyclic region function to calculate the vibration frequency of the whole disk through a sectoral bladed disk model.The calculation results include different frequencies under each node diameters. Then I extracted the mass matrix and stiffness matrix of the single sector blisk with the Cyclic Region boundary condition. Using the extracted matrix, I calculated its mode shape, which is the same as the mode shape under 0node diameter calculated by ansys. I want to know how to extract the stiffness matrix and mass matrix under other node diameters.

[dlooman]

The difference between the stiffness matrix at different harmonic indices is the constraint equations created to enforce the harmonic index shape.  These constraint equations are created during solution.  A possible way to create a model for a harmonic index greater than 0 is to issue the command cycopt,hindex,N in a commands object.  Then the system matrices will be only for harmonic index N.