After GA is complete (or interrupted with the Stop button) the
Results and Export menu options become enabled. The selections
in the Results menu allows the user to visualize the Cross-Orthogonality,
Pseudo-Orthogonality, Cross-MAC, Self-MAC, frequency comparisons, ASET,
and TAM costs for any Seed TAM and the GA TAM for all FEM configurations.
Users can also view the various TAM DOF directly on the FEM. The Rank DOF option is only available for the GA TAM. These plots provide the user a convenient way to assess the quality of
the Seed or GA TAMs without leaving the GA form. The Results menu
options are shown in Figure 4 and a sample
of the resulting plots for two FEM configurations are shown in Figure
5. If batch mode is used (more than on entry in the Total
# Accels field), then all menu options display results for the
number of accelerometers shown in the Total
# Accels field. (See Figure
2)
Figure 4. Results menu options
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Figure 5. Pseudo-Orthogonality
plots generated from ResultsàPseudo-OrthogonalityàGenetic Algorithm selection
The cost of all Seed TAMs and the GA TAM is available in ResultsàTAM Cost, and sample results
for a two-FEM configuration GA run is shown in Figure
6. (A detailed description of each cost function is provided in the
Cost Function section). Note that each
Seed TAM for each FEM configuration was created with all accelerometers
specified in the Total # Accels input box while the Genetic Algorithm
TAM only has a subset of the Total # Accels on FEM configuration
1 (because FEM configuration 1 is a subset of FEM configuration 2).
The rank of each GA-selected DOF can be viewed using the Rank DOF menu option in ResultsàRank DOF, which creates a form as shown in Figure 7. The rank for each DOF is computed as the ratio of the cost of the GA set excluding that DOF to the nominal GA cost. A large rank indicates a DOF that is critical to the GA cost while a rank of 1 indicates that the removal of the specified DOF will not change the GA cost at all. This allows the user to quickly identify any DOF which do not contribute to the overall GA cost. The rank can be computed for each individual DOF or on a node-by-node basis. Using the nodal basis, the rank of each node (and all DOF on that single node) are computed together. Keep in mind that the computed ranks are only valid about the nominal GA set. For example, if two DOF have a rank of 1 that does not necessarily mean that both DOF can be removed without detrimentally affecting the overall GA cost. The Manually Edit DOF form allows users to interactively add and remove DOF and assess the various accelerometer sets. This form will be discussed in more detail in a later section.
The Orthogonality, MAC, and frequency comparison data for any Seed TAM
or the GA TAM can also be exported to an Excel-compatible XML file by
using the Export menu options. One XML file will be written for
each FEM configuration and the user is prompted for each file name. Figure 8 shows the Export menu options
and Figure 9 and Figure
10 show samples from the Excel-compatible XML file. The grey rows in
frequency comparison table in Figure 9 are
the non-target modes and are included for reference. The color coding
in all XML sheets are meant to provide quick visual identification of
the fitness of the accelerometer set where green is good, yellow is marginal,
and red is poor. Figure 10 shows that the
Pseudo-Orthogonality of the candidate set TAM to the Genetic Algorithm
TAM is excellent.
Figure 9. Sample XML Frequency
table
Figure 10. Sample Pseudo-Orthogonality XML results
The Plot FEMresults menu option displays the selected TAM DOF directly on the FEM in an interactive window as shown in Figure 11. The FEM can be rotated, zoomed, and panned, and element display can be turned on and off to examine the selected DOF.
Figure 11. TAM DOF viewed directly on FEM using the Plot ASET menu option.