# .force file

The .force file is an OptiStruct ASCII format results file.

Attention: Valid for Implicit and Explicit Analysis

## File Creation

Creation of this file is controlled by the FORCE (ELFORCE) I/O Option.

## File Contents

Result Description
Force Force results from Linear Static Analysis for ELAS (CELAS1, CELAS2, CELAS3, CELAS4), ROD (CROD), BAR (CBAR, CBEAM), BUSH (CBUSH), PLATE (CQUAD, CTRIA), and GAP (CGAP) elements.

Force results from Normal Modes Analysis for ELAS (CELAS1, CELAS2), ROD (CROD), BAR (CBAR), PLATE (CQUAD4, CQUAD8, CTRIA3, CTRIA6, CSHEAR), SHEAR (CSHEAR), BUSH (CBUSH), GAP (CGAP, CGAPG), CONTACT (CGAPG), WELD (CWELD), and FAST (CFAST) elements.

## File Format

The file is divided up by iteration. Output from each iteration starts with a line in the following format:
 ITER Iteration_number Number_of_subcases/Number_of_Modes
Where,
Data
Description
ITER
Keyword denoting the beginning of a new iteration.
Iteration_number
Iteration number.
Number_of_subcases
Number of subcases for which this output is created.
Number_of_Modes
Total number of modes of all subcases for which this output is created.

## Static Analysis

Each iteration section is divided up by subcase. Output for each subcase starts with a line in the following format:
Where,
Data
Description
ID
Output identification number for the subcase. This is not the same as the subcase ID used in the input data.
Number_of_elements
Number of elements for which this output is requested.
Frequency
1.0
Static analysis.
Spc_id
The SID for SPC's referenced by this subcase.
(Datatype)
Keyword indicating the type of subcase involved.
(LOAD) declares data is for a linear static subcase.

## Normal Modes Analysis

Each section under iteration is divided up by subcase. Output for each subcase starts with a line in the following format:
 Id Number_of_elements FREQ: FRID freq Subcase_label
Where,
Data
Description
ID
Output identification number for the subcase.
This is not the same as the subcase ID used in the input data.
Number_of_elements
Number of elements for which this output is requested.
FREQ
Keyword identifying the modal frequency.
FRID
ID of the modal frequency for which output is printed.
Freq
Value of the modal frequency for which the output is printed.
(Datatype)
Keyword indicating the type of subcase involved.

## Linear Static Analysis .force File Example

Each subcase section is divided up by element type. Output for each element type section starts with one of the following formats (depending on the elements present in the model):
ELAS #	FORCE
ROD#	FORCE-A	FORCE-B
BUSH#	F-X	F-Y	F-Z	M-X	M-Y	M-Z
BAR#	END	AXIAL	SHEAR-1	SHEAR-2	TORQUE	BENDING-1	BENDING-2
PLATE#	MEMB-X	MEMB-Y	MEMB-XY	BEND-X	BEND-Y	TWIST-XY	SHEAR-XZ	SHEAR-YZ
GAP#	COMP-X	SHEAR-Y	SHEAR-Z	

Element force output is then listed under these headings, depending on the type of elements for which this output was selected. The format of the element output matches the corresponding header, that is for ROD elements you would get FORCE-A and FORCE-B; whereas, for PLATE elements you would get MEMB-X, MEMB-Y, MEMB-XY, BEND-X, BEND-Y, TWIST-XY, SHEAR-XZ, SHEAR-YZ.

The format is:
 Eid value1 value2 value3 etc.
Where,
Data
Description
Eid
Element identification number.
value#
Force result corresponding to the column header.

## Average Force Results

Average force results are available for CBAR and CBEAM elements only when the AVG option is used in the FORCE (ELFORCE) output request.

The output is printed after the end forces for each element.
<end forces>
BAR #      AXIAL      SHEAR-1     SHEAR-2     TORQUE     BENDING-1   BENDING-2