CHGAREA

Bulk Data Entry Defines the charge density on faces of CHEXA, CPENTA, CTETRA, or CPYRA solid elements.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CHGAREA SID EID Q1 Q2 Q3 Q4 G1 G2 or G3  

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CHGAREA 2 1106 10.0 8.0 5.0 1.0 1 48  

Definitions

Field Contents SI Unit Example
SID Load identification number.

(Integer > 0)

  
EID Element identification number.

(Integer > 0)

  
Q1, Q2, Q3, Q4 Charge density per unit surface area at the corners of the face of the element.
  • Q1 cannot be blank.
  • If Q2, Q3, or Q4 are blank, the current density is uniform and equal to Q1.
  • Q4 has no meaning for a triangular face and may be left blank.

(Real)

  
G1 Identification number of a grid point connected to a corner of the face. For CPYRA elements, this grid must be on an edge of the quadrilateral face.

(Integer > 0)

  
G2 Identification number of a grid point connected to a corner diagonally opposite to G1 on the same face of a CHEXA or CPENTA element.
  • Required data for quadrilateral faces of HEXA and PENTA elements only.
  • 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.

(Integer or blank)

  
G3 TETRA grid identification number located at the corner not on the face being loaded. This is required data and is used for TETRA elements only.  

Comments

  1. Equivalent grid charge densities are computed by linear (or bi-linear) interpolation of load intensity, followed by numerical integration using isoperimetrical shape functions. Uniform load intensity does not necessarily result in equal equivalent grid point loads.
  2. For the 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.
  3. 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 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.
  4. For more information, refer to Piezoelectric Analysis in the User Guide.