Abaqus - When does Abaqus run Craig-Bampton reduction?

Dear friends,

I am trying to generate a substructure based on Craig-Bampton method. However, based on the results, abaqus still runs Guyan-Irons reduction although i select a set of retained modes. Here is my step procedure:

Step - Substructure generation

Evaluate recovery matrix for whole model -- Selected

Compute reduced mass matrix -- Selected

Retained eigen modes -- Selected

from 1 - 100 with a step of 1.

I run the analysis and create a new model, import the substructure and run an eigenvalue analysis. However, i get the exact same frequencies as if i had not chosen any retained eigenmodes (Guyan-Irons reduction).

Any ideas?

Best regards


Abaqus