CBAR
Bulk Data Entry Defines a simple beam element (BAR) of the structural model.
Format
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| CBAR | EID | PID | GA | GB | X1/G0 | X2 | X3 | OFFT | |
| PA | PB | W1A | W2A | W3A | W1B | W2B | W3B |
Example
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| CBAR | 2 | 39 | 7 | 3 | 13 | ||||
| 513 |
Definitions
| Field | Contents | SI Unit Example |
|---|---|---|
| EID | Unique element
identification number. No default (Integer > 0) |
|
| PID | PBAR or PBARL
property entry identification number or string.
Default = EID (Integer > 0 or <String>) |
|
| GA,GB | Grid point identification
numbers of connection points. No default (Integer > 0 or <PartName.number>; GA ≠ GB). 6 |
|
| X1,X2,X3 | Components of vector v, at
end A, measured at end A, parallel to the components of the
displacement coordinate system for GA, or the
basic coordinate system, to determine (with the vector from end A to
end B) the orientation of the element coordinate system for the BAR
element. 4 No default (Real) |
|
| G0 | Grid point identification
number to optionally supply X1,
X2, X3. Direction of
orientation vector is GA to
G0. No default (Integer > 0 or <PartName.number>). 6 |
|
| OFFT | Character string
specifying the interpretation of the offset vector specification.
5 Default = GGG (Character or blank) |
|
| PA, PB | Pin flags for bar ends A
and B, respectively. Used to remove connections between the grid
point and selected degrees-of-freedom of the bar. The
degrees-of-freedom are defined in the element's coordinate system.
The bar must have stiffness associated with the
PA and PB
degrees-of-freedom to be released by the pin flags. For example, if
PA=4 is specified, the
PBAR entry must have a value for
J, the torsion stiffness. 1 No default (Integer > 0; up to 5 of the unique digits 1-6 with no embedded blanks) |
|
| W1A,W2A,W3A W1B,W2B,W3B | Components of offset
vectors wa and wb in displacement coordinate systems at points
GA and GB, respectively,
or in the element coordinate system. 4 Default = blank (Real or blank) |
Figure 1. Bar Element Coordinate System (for CBAR element)
Figure 2. Moments and Internal Forces in the x-y Plane (for a CBAR element)
Figure 3. Moments and Internal Forces in the x-z Plane (for a CBAR element)
Comments
- If there are no pin flags or offsets, the continuation may be omitted.
- G0 cannot be located at GA or GB.
- If X1/G0 is a positive integer and X2 and X3 are blank, then G0 is used to orient the element, otherwise X1, X2, X3 is used.
-
The OFFT character string specifies how the offset and orientation vector components are computed. By default, the offset vectors are specified in the Global (local displacement) coordinate system of each grid A and B, and the orientation vector is specified in the Global coordinate system of grid A. Using the codes below, the offset vector can be specified in the element coordinate system and the orientation vector can be specified in the basic coordinate system. The valid character strings and their meanings are:The element system x-axis is defined from GA to GB. The orientation vector and the element system x-axis are then used to define the z and y axes of the element system. A vector is formed from the cross product of a vector going from Grid A to Grid B and the orientation vector to create the element coordinate z-direction.
OFFT Orientation Vector End A Offset End B Offset GGG Global Global Global BGG Basic Global Global GGO Global Global Element BGO Basic Global Element GOG Global Element Global BOG Basic Element Global GOO Global Element Element BOO Basic Element Element - Offset vectors are treated like rigid elements. The length of the offset vectors is not affected by thermal loads.
- Supported local entries in specific parts can be referenced by the use of "fully-qualified references" on CBAR entries in the model. A fully-qualified reference ("PartName.number") is similar to the format of a numeric reference. "PartName" is the name of the part that contains the referenced local entry (part names are defined on the BEGIN Bulk Data Entry in the model). "number" is the identification number of a referenced local entry in the part "PartName". Refer to Parts and Instances in the User Guide for detailed information on the use of fully-qualified references.
- String based labels allow for easier visual identification of properties, when being referenced by the elements cards. For more details, refer to String Label Based Input File in the Bulk Data Input File.
- In the ASCII
.force file below, the SHEAR-1 and BENDING-1 values are
associated with Plane-1, while SHEAR-2 and BENDING-2 values are associated with
Plane-2 in Figure 1.
ITER 0 1 1 1 LOAD: 2 (LOAD) Transverse_Load BAR #-END AXIAL SHEAR-1 SHEAR-2 TORQUE BENDING-1 BENDING-2 1-A 0.000E+00 0.000E+00 -2.5000E+02 0.000E+00 0.000E+00 -2.5000E+04 1-B 0.000E+00 0.000E+00 -2.5000E+02 0.000E+00 0.000E+00 1.4552E-11 - This card is represented as a bar2 element in HyperMesh.