Substructure generate problem

[JoeJoyce]

Hi all,

I'm trying to extract the reduced mass and stiffness matrices from my FE model. I'm using Abaqus 6.13-2 and this is the bit I've introduced into my .inp file:

*STEP, name=CB
*SUBSTRUCTURE GENERATE, TYPE=Z66, MASS MATRIX=YES
*RETAINED NODAL DOFS
101, 13809, 45225
1
5
*SELECT EIGENMODES, DEFINITION=MODE NUMBERS, GENERATE
1
10
1
*SUBSTRUCTURE MATRIX OUTPUT, OUTPUT FILE=USER DEFINED, FILE NAME=B1_CB_MATRICES, MASS=YES, RECOVERY MATRIX=YES, STIFFNESS=YES
*END STEP

The error messages I've got are the following:

Error in job B1_CB-1: in keyword *SUBSTRUCTUREGENERATE, file "B1_CB.inp", line 87866: The following option is currently not supported in a model defined in terms of an assembly of part instances: *SUBSTRUCTURE GENERATE
Error in job B1_CB-1: in keyword *RETAINEDNODALDOFS, file "B1_CB.inp", line 87867: Unknown assembly id 101.
Error in job B1_CB-1: in keyword *RETAINEDNODALDOFS, file "B1_CB.inp", line 87867: Unknown assembly id 1.
Error in job B1_CB-1: in keyword *RETAINEDNODALDOFS, file "B1_CB.inp", line 87867: Unknown assembly id 5.
Error in job B1_CB-1: RETAINED NODES CANNOT BE LESS THAN OR EQUAL TO ZERO
Error in job B1_CB-1: RETAINED NODES CANNOT BE LESS THAN OR EQUAL TO ZERO
Error in job B1_CB-1: RETAINED NODES CANNOT BE LESS THAN OR EQUAL TO ZERO
Error in job B1_CB-1: NO VALID RETAINED NODE HAS BEEN READ.
Error in job B1_CB-1: YOU CANNOT GENERATE BETWEEN 1 AND 0 WITH AN INCREMENT OF 1
Error in job B1_CB-1: RETAINED NODAL DOFS FOR SUBSTRUCTURE GENERATION STEP 1 ARE NOT SPECIFIED. THE RETAINED NODAL DOFS OPTION MUST APPEAR IN A SUBSTRUCTURE GENERATE PROCEDURE.

Could anybody give me a hand on this one?

Thanks in advance,

Joe