LS-PrePost Files

Many LS-DYNA preprocessors and postprocessors exist, such as Ansys or LS-PrePost. Because LS-PrePost is free and widely used, it serves as a reference data file format specification. The typical file extension for an LS-PrePost output data file is .k.

You can import LS-PrePost output files into oSP3D. While the data file format requirements for importing these output files are very similar to those given for importing LS-DYNA input files, oSP3D requires that the following specifications also be met:

The LS-PrePost data interface skips all content up to the required *KEYWORD card.
The LS-PrePost data interface ignores the optional *END card and continues parsing until the end-of-file marker is encountered.
The number of characters per input line is not limited and is terminated by the first line break sequence.
Fields within one line are separated by one or more spaces.

Of the many data output types provided by LS-PrePost, the oSP3D LS-DYNA import data interface supports importing the output data structures that follow the general steps that you must perform to get a result file within LS-PrePost:

Open a LS-DYNA d3plot project file.
Select the state or time at which the data is to be exported.
Plot the so-called fringe component that you want to export to oSP3D.
For example, in the command line, type either fringe 7 to print the plastic strain data at the current state or time or fringe 68 to print the thickness reduction.
Write the data to an output file using either the GUI menu in [POST] -> [OUTPUT] or one of the commands that follow for the data structures that are supported by the oSP3D LS-DYNA import interface.

*NODAL_RESULTS

The next line starts with $RESULT OF, followed by the data identifier.
The following lines are expected to contain the nodal identifier, separated from the actual nodal scalar data value at a specific finite element solver state or time, such as a nodal displacement or stress or strain component.
```
*KEYWORD
$TIME_VALUE = 1.0099823e-003
$STATE_NO = 102
$Output for State 102 at time = 0.00100998
*END
$NODAL_RESULTS
$RESULT OF Y-displacement
         1       0.0
         2 1.3924E+1
```
To create this output file using LS-PrePost, you must perform the general steps given earlier and include this:
```
fringe 18
output "absolute or relative dir path\nodal_y-displacement.k" 102 1 0 1 0 0 0 0 0 1 0 0 0 0 0 1.000000
```

*NODAL_DISPLACEMENT

The following lines are expected to contain the nodal identifier, separated from the actual nodal displacements in the x, y, and z directions at a specific finite element solver state or time:

*KEYWORD
$TIME_VALUE = 1.0099823e-003
$STATE_NO = 102
$Output for State 102 at time = 0.00100998
*END
$NODAL_DISPLACEMENT
       1  0.0000000e+000  0.0000000e+000 -1.7422426e+001
       2  0.0000000e+000  1.3924263e+001 -1.9328943e-002

To create this output file using LS-PrePost, you must perform the general steps given earlier and include this:
```
output "absolute or relative dir path\displacements.k" 102 1 0 1 0 0 1 0 0 0 0 0 0 0 0 1.000000
```

*SHELL_ELEMENT_RESULTS

The next line starts with $RESULT OF, followed by the data identifier.
The following lines are expected to contain the element identifier, separated from the actual element scalar data value at a specific finite element solver state or time, such as an element shell thickness (reduction) or von Mises stress.
```
*KEYWORD
$TIME_VALUE = 1.0099823e-003
$STATE_NO = 102
$Output for State 102 at time = 0.00100998
*END
$SHELL_ELEMENT_RESULTS
$RESULT OF Shell Thickness (Unaveraged)
       1  9.0582311e-002
       2  8.7422013e-002
```
To create this output file using LS-PrePost, you must perform the general steps given earlier and include this:
```
fringe 67
output "absolute or relative dir path\shell_thickness.k" 102 1 0 1 0 0 0 0 1 0 0 0 0 0 0 1.000000
```

*ELEMENT_SHELL_PRINCIPAL_TRUE_STRAIN

The following lines are expected to contain the element identifier separated from the actual element scalar data value at a specific finite element solver state or time.

*KEYWORD
$TIME_VALUE = 1.0099823e-003
$STATE_NO = 102
$Output for State 102 at time = 0.00100998
*END
$ELEMENT_SHELL_PRINCIPAL_TRUE_STRAIN()
$Elem Id   Lower Major   Lower Minor   Upper Major   Upper Minor    Thickness    Reduction
       1  1.21473e+001 -1.02536e+001  1.22579e+001 -1.01161e+001  9.05823e-002  2.01938e+000
       2  7.35848e+000 -7.53077e-001  6.47487e+000 -2.00809e+000  8.74220e-002  5.57624e+000

To create this output file using LS-PrePost, you must perform the general steps given earlier and include this:
```
output "absolute or relative dir path\shell_p-strain.k" 102 1 0 1 0 0 0 0 0 0 1 0 0 0 0 1.000000
```