QTRAN Input Date File (QINDAT) is used as a command file by the Patran Thermal system. PATQ will supply bulk data files created from the PATRAN Plus model which are referenced by the QINDAT file with $INSERT commands. This greatly reduces the size of the QINDAT file, allowing a relatively small (usually about 60-70 significant data lines) command file for QTRAN. An example QINDAT file is provided with the Patran Thermal delivery and in QINDAT File Listing, 579. This file is heavily commented to make it easier to locate and understand the various input data file parameters that are normally placed in QINDAT. Section references in the QINDAT file refer to the input sections discussed in this chapter.

If QTRAN detects a data mismatch when reading the input data file, QTRAN will print out the image and number of the input data file line that was being read when the error was detected. This feature can greatly ease the debugging of an input data file. After encountering such an error, QTRAN will terminate program execution normally. QTRAN uses a free format input data file structure, so there is no concern about getting data in correct columns. Most data lines begin with keywords such as MDATA for material property data, CAP for capacitor data, etc. These keywords allow QTRAN to verify that what it is currently reading at a particular part of the data file is what it should be reading. Although the data is free format, the order in which the data is entered is very tightly controlled. All keywords specified in the QINDAT file must be input in the order encountered in this chapter. New keywords have been added for the enhancements in Patran Thermal. The QINDAT file can be obtained from the STARTUP directory with the GET_QTRAN command which will provide a sample input file indicating keyword order dependence. This is done for a number of reasons, including CPU efficiency. The most important reason why QTRAN input data is in fixed order format, however, is that it guarantees that each QTRAN input file (QINDAT) will look approximately the same without having important control parameters buried somewhere where a later user may not expect them to be found. With a fixed order format, it is easier to look for a particular parameter if it needs changing.

To insert comment lines anywhere in the input data file to document the input data, begin the line with an asterisk (*) or semicolon (;) in column 1. QTRAN will ignore any input data file line that begins with an asterisk or semicolon. QTRAN will also treat a semicolon as an end-of-line terminator, so that comments may be placed to the right of a semicolon. These comments can be valuable for documenting input data files for later reference.

QTRAN also offers the following commands that may be embedded in the input data file:

This command is used to restart a calculation. If this command is to be used, it must be the first noncomment line in a QINDAT file. This command causes QTRAN to read a QTRAN nodal results file filename as a restart file. Since QTRAN creates nodal results files with the name NRnnnNRF, the parameter next_nnn allows the nnn value to be specified for the next NRnnnNRF file that QTRAN will generate after being restarted. For example, a $RESTART command may look as follows: TIME is a value that will be used as initial time for the subsequent run rather than the time from the restart file. OVRWFL is an over write flag that allows specified initial temperatures to replace temperatures specified in the nodal results file.

$RESTART NR127.NRF 200 0.0 1

This command would cause QTRAN to read in NR127.NRF as a restart file. The next NRnnnNRF file that QTRAN generates will be named NR200.NRF. QTRAN reads the time and temperatures from the NRnnnNRF file. The time overrides TSTART and the temperatures override any TEMP data. If a TIME has been defined on the restart card, it overrides all other times and is used for TSTART to continue the run.

Defining the over write flag OVRWFL with something greater than zero will cause any temperatures specified in the TEMPDAT file to over write those specified in the restart file. This allows the user to change either initial of fixed temperatures from those specified by the restart conditions. The temperature over write is performed before the user restart function URSTRT is called. URSTRT is always the final restart operation.

Inserts the file filename into the input data file stream at this point. Nesting of $INSERT commands is permitted. The depth of file nesting is currently limited to ten deep. This command must begin in column one of any line in the input data file and there must be exactly one space between $INSERT and the file name.

Enables or disables, respectively, the printing of input data file information into the output data file at the point where the $ECHO_ON or $ECHO_OFF command is encountered. These commands must begin in column 1 of any line in the input data file.

Sends the remainder of the input data file line to the status file. This can be used to keep track of QTRAN when large data files have been prepared, or to debug input data files.

Commands QTRAN to send each line of the input data file to the status file as it is read. This is used primarily for debugging purposes.