Additional Output and Repeat Runs |
 
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Additional Output and Repeat Runs |
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Modes produces one further category of output to help assess SHEAR7 data. This is output at the end of the main output file, and consists of a table of the maximum curvature in each mode of the eigensolution. Two values are output for each mode. One is calculated by looping over each integration point on each element, and the other by looping over the end of each segment of equal length – recall these segments are the basis for the actual SHEAR7 output. The intention here is to allow you to decide if you have specified enough segments to accurately capture the actual element-by-element modal curvature distribution.
If an examination of this output leads you to conclude you actually need more segments, then one option is obviously to rerun your Modes analysis in full but with a larger number of segments specified. Likewise if the plots described in the last section show your SHEAR7 output included mixed modes, once again you may want to rerun your modal analysis to exclude these modes. Now a modal analysis in which you request a very large number of modes (say, 150 or more) can take some time to complete. And anyway the calculation of SHEAR7 output, as noted earlier, is purely a postprocessing operation, so repeating the eigensolution in full could be avoided. This is the rationale for the so-called Repeat Run capability.
This is how it works. Modes automatically creates a “restart” file at the end of each program run, which contains sufficient information for repeat run analyses. If you nominate that an analysis as a repeat run, Modes reads the eigensolution details from the restart file, and proceeds directly to generating the SHEAR7 data. In addition to changing the number of riser segments or excluding specific modes, you can also change the element set for SHEAR7 output, or the lowest number of modes that Modes can consider for this output. You can also use this option to change the contents of the program output file. Note though that only parameters relating to SHEAR7 file generation can be altered in a repeat run. You cannot for example change the required number of eigenpairs, and indeed Modes will terminate with an error if you attempt to do so. The program also terminates with an error in a repeat run if a relevant restart file does not exist.
•*REPEAT ($MODES section) is used to specify that the present Modes analysis is a Repeat Run.
•*EXCLUDE MODES ($MODES section) is used to specify modes to be excluded from SHEAR7 output.
•*INCLUDE MODES ($MODES section) is used to specify modes to be included in SHEAR7 output.
•*REPLACE MODES ($MODES section) is used to specify modes to be replaced in SHEAR7 output.
•*OUTPUT OPTIONS ($MODES section) is used to specify the eigensolution details to be routed to the output file.
•*RISER TYPE ($MODES section) is used to specify the riser type and other parameters relating to the Modes facility for generating output for subsequent input to SHEAR7.