How do I get ANSYS to output the global stiffness matrix of a part?


You can use the HBMAT command to output the global stiffness matrix in the Harwell-Boeing format.

HBMAT, Fname, Ext, --, Form, Matrx, Rhs

Writes an assembled global matrix in Harwell-Boeing format.

AUX2: Binary Files

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Fname
File name and directory path (248 characters maximum, including the characters needed for the directory path). An unspecified directory path defaults to the working directory; in this case, you can use all 248 characters for the file name.

Defaults to the current Jobname if left blank.

Ext
Filename extension (8 character maximum).

Defaults to .matrix if left blank.

--
Unused field.

Form
Specifies format of output matrix file:

ASCII ` Write output matrix file in ASCII form.

BIN ` Write output matrix file in binary form.


Matrx
Specify which matrix to write to the output matrix file:

STIFF ` Write stiffness matrix to output matrix file. Valid for all types of analyses that write a .FULL file.

MASS ` Write mass matrix to output matrix file. Valid for buckling, substructure, and modal analyses. If .FULL file was generated in a buckling analysis, then this label will write stress stiffening matrix to output matrix file.

DAMP ` Write damping matrix to output matrix file. Only valid for damped modal analyses.


Rhs
Specifies whether to write the right-hand side vector to output matrix file:

YES ` Write right-hand side vector to output matrix file

NO ` Do not write right-hand side vector to output matrix file


Command Default
By default, assuming a proper filename and extension have been entered, writes the stiffness matrix and right-hand side vector to jobname.matrix in the current working directory in ASCII format.

Notes
This command is used to copy a matrix from the assembled global matrix file (.FULL file) or from the superelement matrix file (.SUB file) as specified on the FILE command and write it in Harwell-Boeing format to a new file, named jobname.MATRIX. The Harwell-Boeing format is widely used by other applications that deal with matrices.

The assembled global matrix file is created during solution depending on the analysis type, equation solver, and other solution options. By default, the assembled global matrix file is never deleted at the end of solution. For most analysis types, the Sparse direct solver, the ICCG solver, and the AMG solver (when available) will write a .FULL file. For buckling and modal analyses, most mode extraction methods will write a .FULL file. However, currently only the Block Lanczos and QR-damped mode extraction methods will write a properly formatted .FULL file to be used with the HBMAT command.

The WRFULL command, in conjunction with the SOLVE command, can be used to generate the assembled global matrix file and eliminate the equation solution process and results output process.

The Harwell-Boeing format is column-oriented. That is, non-zero matrix values are stored with their corresponding row indices in a sequence of columns. However, since the ANSYS matrix files are stored by row and not column, when the HBMAT command is used with a non-symmetric matrix, the transpose of the matrix is, in fact, written.

When dumping the stiffness matrix for transient and harmonic analyses, be aware that the element mass matrix values (and possibly element damping matrix values) are incorporated into the globally assembled stiffness matrix. Thus, the globally assembled stiffness matrix represents more than the stiffness of the model. Please refer to the ANSYS, Inc. Theory Reference for more details.

Distributed ANSYS Restriction. This command is not supported in Distributed ANSYS.

Menu Paths
Utility Menu>File>List>Binary Files
Utility Menu>List>Files>Binary Files





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