The following descriptions relate to automatic output that is associated with particular types of solution sequences.
Detailed information on the force and stress output available for each element type is given in the NX Nastran Element Library.
Real Eigenvalue Analysis
Each eigenvalue is identified with a mode number determined by sorting the eigenvalues by their magnitude. The following summary is also automatically printed for all methods:
• Mode number
• Extraction order (this is irrelevant under the Lanczos method)
• Eigenvalue
• Frequency (radians)
• Frequency (Hz)
• Generalized mass
• Generalized stiffness
Note: For all methods except the Inverse Power Method, if the orthogonality criterion fails, then the software issues User Warning Message 3034.
Lanczos Method Additional Summary Content
• Block size used
• Number of decompositions
• Number of roots found
• Number of (block) solves required
• One of the following termination messages:
– Required number of eigenvalues found – Not all the roots found within the range – All eigenvalues found within the range – Insufficient time to find more eigenvalues Inverse Power Method Additional Summary Content
• Number of eigenvalues extracted
• Number of starting points used
• Number of starting point moves
• Number of triangular decompositions
• Number of vector iterations
• The reason for termination is indicated by one of the following numbers:
Reason
Number Description
1 Two consecutive singularities encountered while performing triangular decomposition
2 Four shift points while tracking a single root
3 All eigenvalues found in the frequency range specified
Reason
Number Description
4 Three times the number of roots estimated in the frequency range have been extracted
5 All eigenvalues that exist in the problem have been found 6 The number of roots desired have been found
7 One or more eigenvalues have been found outside the frequency range specified
8 Insufficient time to find another root 9 Unable to converge
• Largest off-diagonal modal mass term identified by mode pair
• Number of off-diagonal mass terms failing orthogonality criterion Complex Eigenvalue Analysis
Each complex eigenvalue is identified with a root number determined by sorting the complex eigenvalues by magnitude. The following summary of the complex eigenvalues extracted is automatically printed for all methods:
• Root number
• Extraction order (this is irrelevant under the Lanczos method)
• Real and imaginary parts of the eigenvalue
• The coefficients f (frequency) and g (damping coefficient) in the following representation of the eigenvalue (p =α + iω):
Equation 4-1.
Therefore,
Equation 4-2.
Equation 4-3.
Complex Lanczos Method
If you use the complex Lanczos method, the software also issues User Information Messages 5444, 5445, and 5453.
Determinant Method
If you use the Determinant method, the software also prints:
• Number of eigenvalues extracted
• Number of passes through starting points.
• Number of criteria changes
• Number of starting point moves
• Number of triangular decompositions
• Number of failures to iterate to a root
• Number of predictions outside region
• The reason for termination is indicated by one of the following integers:
Reason
Number Description
1 The number of roots desired have been found
2 All predictions for eigenvalues are outside the regions specified 3 Insufficient time to find another root
4 Matrix is singular at the first three starting points
• swept determinant functions for each starting point Inverse Power Method
The following summary is automatically printed for each region specified when the Inverse Power method is used:
• Number of eigenvalues extracted
• Number of starting points used
• Number of starting point or shift point moves
• Number of triangular decompositions
• Number of vector iterations
• The reason for termination is indicated by one of the following integers:
Reason
Number Description
1 Two consecutive singularities encountered while performing triangular decomposition
2 Four starting point moves while tracking a single root 3 All eigenvalues found in the region specified
4 Three times the number of roots estimated in the region have been extracted 5 All eigenvalues that exist in the problem have been found
6 The number of roots desired have been found
7 One or more eigenvalues have been found outside the region specified 8 Insufficient time to find another root
9 Unable to converge Superelement Analysis
• Superelement mapping information that lists the membership of grid points and elements in the superelements, the order in which the superelements will be processed, and timing and space estimates for each superelement
• A page header that identifies the superelement for which the printed information on the page pertains
• Matrices wherein mechanisms are identified
• Resultants of external loads
• Maximum applied loads
• Maximum displacements
• Maximum SPC forces
For SOL 101, if PARAM,INREL,-1 or PARAM,INREL,-2, the following data is printed automatically:
INTERMEDIATE MATRIX...QRR
This is the rigid body mass matrix of the total structure, including superelements. It is presented as a 6 × 6 matrix, measured at the reference grid point, in its global coordinates. Masses on scalar points are ignored.
INTERMEDIATE MATRIX...QRL
This is the resultant of the applied loads, measured at the reference point. There is one column for each loading condition.
INTERMEDIATE MATRIX...URACCEL
This is the user-supplied rigid body acceleration, input on the DMIG,UACCEL entry. This output does not appear if the entry is not present.
INTERMEDIATE MATRIX...URA
This is the rigid body acceleration matrix, computed from the applied loads.
4.3 Understanding the .f04 File
The .f04 file contains information that helps you monitor and tune the performance of your analysis job. For example, the .f04 file contains:
• A summary of physical file information that describes the files used for DBsets
• A map showing memory allocation
• A “day log” that provides a DMAP execution summary
• A listing of memory and disk usage statistics
• A listing of database usage statistics that summarizes the I/O activity for the DBsets
• A summary of physical file I/O activity for each database file
• Module execution and statistical information
• Other optional diagnostic information as requested by the DIAG executive control command in the input file
If you’re performing an analysis using NX Nastran’s global iterative solver, the .f04 file also contains important performance diagnostic information about the solver.
The software writes the .f04 file to FORTRAN unit 4.
See also
• “Flushing .f04 and .f06 Output to Disk (UNIX)” in the NX Nastran Installation and Operations Guide
• “Performance Diagnostics” in the NX Nastran Numerical Methods User’s Guide