Wheels Analyzer (FEROT)

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The MSC.Fatigue analysis module FEROT performs a number of tasks including Global Analysis, Results Listing, and Time history extractions. Module operation of each of these tasks is described in detail in this section.

The operation of FEROT can be in three modes: by spawning from the MSC.Fatigue Pre & Post or MSC.Patran environment, in stand alone mode by typing ferot at the system prompt or in batch mode. The only difference is that in stand alone mode, the user must supply the jobname. (In direct mode from MSC.Patran, these are passed to FEROT automatically). Once FEROT has been initiated in either of these modes, two windows will be presented with the Motif driver. The top, small form is a generic form and allows for general program control. This is discussed in detail in Module Operations (Ch. 17) for the Motif driver.

The main menu appears as follows. Each item is discussed in this section.

1. Analyse - This option will rerun the analysis interactively for you. If this it is a computationally intensive operation, you may find it more convenient to run in batch mode. See Analyze, 836.

2. Results post-process - This option will put you in another menu to allow for sensitivity studies and design optimization tasks.

Note that the fatigue analysis may take some time. It may be worth considering operating FEROT in batch. Batch operation is discussed in FEROT Batch Operation on page .

When the “Estimate Fatigue Life” option has been selected, the user will be presented with a number of questions. The first question asks for the input file name. Press the OK button once a file name (jobname.fes) has been selected. Use the List button to list all available input files. These files have been created by the PAT3FAT or FATTRANS translator. The default will be the last jobname.fes created.

The following table explains each entry on the previous form.

Field	Description
Input Filename	This is the fatigue input file name (jobname.fes) to be used in the fatigue pre-processing. The job must have already run at least through the PAT3FAT or FATTRANS translator to produce a jobname.fes file. This is achieved by carrying out a full or translate only submission from the job submit options in the MSC.Fatigue menus of MSC.Patran, or by running PAT3FAT (or FATTRANS) in stand-alone mode (see The Translator (PAT3FAT or FATTRANS), 272). To select a jobname from a list of available jobs, use the List button. Once the file name has been supplied and the screen inputs accepted, the rest of the input options will be displayed.
Output filename	The default is the jobname. After processing jobname.fef will exist. You will be requested to overwrite any existing output file of the same name if one exists.
Create ROT file	If yes is toggled a jobname.rot will be created. You will be requested to overwrite any existing rot file of the same name if one exists.

Field

Description

Input Filename

This is the fatigue input file name (jobname.fes) to be used in the fatigue pre-processing. The job must have already run at least through the PAT3FAT or FATTRANS translator to produce a jobname.fes file. This is achieved by carrying out a full or translate only submission from the job submit options in the MSC.Fatigue menus of MSC.Patran, or by running PAT3FAT (or FATTRANS) in stand-alone mode (see The Translator (PAT3FAT or FATTRANS), 272).

To select a jobname from a list of available jobs, use the List button. Once the file name has been supplied and the screen inputs accepted, the rest of the input options will be displayed.

Output filename

The default is the jobname. After processing jobname.fef will exist. You will be requested to overwrite any existing output file of the same name if one exists.

Create ROT file

If yes is toggled a jobname.rot will be created. You will be requested to overwrite any existing rot file of the same name if one exists.

When this form is complete, select OK and the analysis will run. While the analysis is running, a form appears which shows the progress of the analysis.

When the analysis is complete .

The following form is displayed when this option is selected:

The results post-process is a utility for filtering the results from an analysis since the output can be quite extensive depending on the analysis set and the number of load conditions run. The following table explains each entry on the previous form.

Field	Description
Input results filename	This is the .rot file (jobname.rot) that must be available from a previous analysis (jobname.fes). To select a .rot file from a list of available jobs that have been run, use the List button. Once the file name has been supplied and the screen inputs accepted, the rest of the input options will be displayed.
Extract	Specific Angle : When this is selected, the Angle to extract text box is activated for entry. This angle is dependent on the surface angle entry on solution control form (page ).Only an integer multiple of the surface angle may be specified e.g. if the surface angle for the critical plane analysis was specified as 10 degrees, results may only be extracted for angles in ten-degree increments up to 360 degrees. Worst Case: This extracts the worst (lowest life, maximum damage) results for all conditions including the worst case (accumulated damage from all load conditions)
Output Filename	Enter the name of the output file. This file will have a .fef extension and can either be listed or read back into the PATRAN database by specifying the same Jobname as this output file.

Field

Description

Input results filename

This is the .rot file (jobname.rot) that must be available from a previous analysis (jobname.fes). To select a .rot file from a list of available jobs that have been run, use the List button. Once the file name has been supplied and the screen inputs accepted, the rest of the input options will be displayed.

Extract

Specific Angle : When this is selected, the Angle to extract text box is activated for entry. This angle is dependent on the surface angle entry on solution control form (page ).Only an integer multiple of the surface angle may be specified e.g. if the surface angle for the critical plane analysis was specified as 10 degrees, results may only be extracted for angles in ten-degree increments up to 360 degrees.

Worst Case: This extracts the worst (lowest life, maximum damage) results for all conditions including the worst case (accumulated damage from all load conditions)

Output Filename

Enter the name of the output file. This file will have a .fef extension and can either be listed or read back into the PATRAN database by specifying the same Jobname as this output file.

This option allows the extraction of stress time histories (.DAC) files.

Field	Description
Input fes filename	Enter the jobname.fes filename. To select a .fes file from a list of available jobs that have been run, use the List button. Once the file name has been supplied and the screen inputs accepted, the rest of the input options will be displayed.
Calculation points	Enter the node number for extraction. To browse the nodes in the analysis set use the list button and enter the node number from the displayed list.
Load conditions	Enter the load condition number. To browse the available load conditions, use the list button and enter the load condition from the displayed list.
Angle (degrees)	Enter the surface angle at which the time history is desired. Remember this is dependent on the surface angle specified on the solution control form and only multiples of that angle may be specified.
Generic file root	The default output filename is the jobname_node_loadcondition_angle.dac.A plot of the extracted time history will be displayed automatically.

Field

Description

Input fes filename

Enter the jobname.fes filename. To select a .fes file from a list of available jobs that have been run, use the List button. Once the file name has been supplied and the screen inputs accepted, the rest of the input options will be displayed.

Calculation points

Enter the node number for extraction. To browse the nodes in the analysis set use the list button and enter the node number from the displayed list.

Load conditions

Enter the load condition number. To browse the available load conditions, use the list button and enter the load condition from the displayed list.

Angle (degrees)

Enter the surface angle at which the time history is desired. Remember this is dependent on the surface angle specified on the solution control form and only multiples of that angle may be specified.

Generic file root

The default output filename is the jobname_node_loadcondition_angle.dac.A plot of the extracted time history will be displayed automatically.

Batch operation has the following batch keywords:

/INPut	The name of the input job (/INP=myjob)
/OUTput	The name of the output file (/OUT=newname)
/OPTion	This is the option as shown on the main screen (A,R,E.X) (/OPT=e)
/CRE	Create the ROT file (Y,N)
/NUMEQU	Number of Equivalent Units
/MINers	This is the Miner’s Sum. Valid from 0.5 to 2.0 generally. (/MIN=1.0)
/NANGD	Number of Angles for Calculation
/NUGGET	Calculate Nugget? (Y or N)
/OVerwrite	Overwrite (yes or no) (/OV=yes)
/*	Output to.... (TT = screen, Filename = to file, None = None)

/INPut

The name of the input job (/INP=myjob)

/OUTput

The name of the output file (/OUT=newname)

/OPTion

This is the option as shown on the main screen (A,R,E.X) (/OPT=e)

/CRE

Create the ROT file (Y,N)

/NUMEQU

Number of Equivalent Units

/MINers

This is the Miner’s Sum. Valid from 0.5 to 2.0 generally. (/MIN=1.0)

/NANGD

Number of Angles for Calculation

/NUGGET

Calculate Nugget? (Y or N)

/OVerwrite

Overwrite (yes or no) (/OV=yes)

Output to.... (TT = screen, Filename = to file, None = None)

This batch line would run a spot weld analysis in batch where the first option is called out (Estimate Fatigue Life) and the jobname is myjob. All the defaults are used for the rest of the inputs such as matrix size and Miners sum. The results files will be called jobname.fef and jobname.spt by default.