PLOAD4
Bulk Data Entry Defines a load on a face of a HEXA, PENTA, TETRA, PYRA, TRIA3, TRIA6, QUAD4, or QUAD8 element.
It can also be used to define the EXCITEID field (Amplitude "A") of dynamic loads in RLOAD1, RLOAD2, TLOAD1 and TLOAD2 Bulk Data Entries. Additionally, the PLOAD4 entry can be defined as Follower Loads in Large Displacement Nonlinear Analysis.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
PLOAD4 | SID | EID | P1 | P2 | P3 | P4 | G1 | G3 or G4 | |
CID | N1 | N2 | N3 |
Example
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
PLOAD4 | 2 | 1106 | 10.0 | 8.0 | 5.0 | 1.0 | 1 | 48 | |
6 | 0.0 | 1.0 | 0.0 |
Alternate Format and Example
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
PLOAD4 | SID | EID1 | P1 | P2 | P3 | P4 | "THRU" | EID2 | |
CID | N1 | N2 | N3 | ||||||
PLOAD4 | 2 | 1106 | 10.0 | 8.0 | 5.0 | THRU | 1143 | ||
6 | 0.0 | 1.0 | 0.0 |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
SID | Load set identification
number. (Integer > 0) |
|
EID1, EID2 | Element identification
number. (Integer > 0, EID1 < EID2) |
|
P1, P2, P3, P4 | Load per unit surface area (pressure)
at the corners of the face of the element (real or blank). (P1 is the default for P2, P3, and P4). If P2, P3 (and P4) are blank, the load intensity is uniform and equal to P1. P4 has no meaning for a triangular face and may be left blank. |
|
G1 | Identification number of a grid point
connected to a corner of the face. Required data for solid elements only (Integer
or blank). For PYRA elements, this grid must be on an edge of
the quadrilateral face. G1 is ignored for TRIA3, TRIA6, QUAD4, and QUAD8 elements. |
|
G3 | Identification number of a grid point
connected to a corner diagonally opposite to G1 on the same
face of a HEXA or PENTA element. Required
data for quadrilateral faces of HEXA and
PENTA elements only (Integer or blank). G3
must be omitted for a triangular surface on a PENTA element and
the quadrilateral face on a PYRA element. For triangular faces
of PYRA elements, this grid must be on the edge next to the
quadrilateral face. G1 and G3 must define a
positive direction into the element using the right hand
rule. G3 is ignored for TRIA3, TRIA6, QUAD4, and QUAD8 elements. |
|
G4 | TETRA grid point identification number located at the corner not on the face being loaded. This is required data and is used for TETRA elements only. | |
CID | Coordinate system identification
number. (Integer ≥ 0) |
|
N1, N2, N3 | Components of vector measured in coordinate system defined by CID (Real). Used to define the direction (but not the magnitude) of the load intensity. |
Comments
- The continuation is
optional. If fields 2, 3, 4, and 5 of the continuation are blank, the load is assumed to be
a pressure acting normal to the face. If these fields are not blank, the load acts in the
direction defined in these fields. Note: If CID is a curvilinear coordinate system, the direction of load may vary over the surface of the element. The load intensity is the load per unit of surface area, not the load per unit of area normal to the direction of loading.
- For solid elements the direction of positive pressure (defaulted continuation card) is inward. The load intensity P1 acts at grid point G1 and load intensities P2, P3 (and P4) act at the other corners in a sequence determined by applying the right hand rule to the outward normal.
- For plate elements the direction of positive pressure (defaulted continuation) is in the direction of positive normal, determined by applying the right hand rule to the sequence of connected grid points. The load intensities P1, P2, P3 (and P4) act respectively at corner points G1, G2, G3 (and G4). (See plate connection).
- Equivalent grid point loads are computed by
linear (or bilinear) interpolation of load intensity, followed by numerical integration
using isoperimetric shape functions. Note: That uniform load intensity does not necessarily result in equal equivalent grid point loads.
- The alternate form is available only for TRIA3, TRIA6, QUAD4, and QUAD8 elements. The continuation card may be used in the alternate form.
- For triangular faces of PENTA elements, G1 is an identification number of a corner grid point that is on the face being loaded and the G3 or G4 field is left blank. For faces of TETRA elements, G1 is an identification number of a corner grid point that is on the face being loaded and G4 is an identification number of the corner grid point that is not on the face being loaded. Since a TETRA has only four corner points, this point, G4, is unique and different for each of the four faces of a TETRA element.
- For the quadrilateral face of the PYRA element, G1 is an identification number of a corner grid point on the face and the G3 or G4 field is left blank. For the triangular faces, G1 and G3 must specify the grids on the edge of the face that borders the quadrilateral face and the grids must be ordered so that they define an inward normal using the right hand rule.
- This card is represented as a pressure load in HyperMesh.