CORD2S

Bulk Data Entry Defines a spherical coordinate system three grid points.

The coordinates of the three non-collinear grid points are used to uniquely define the coordinate system.The first point is the origin, the second lies on the Z-axis, and the third lies in the X-Z plane.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CORD2S CID RID A1 A2 A3 B B B  
  C C C            

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CORD2S 3   -2.9 1.0 0.0 3.6 0.0 1.0  
  5.2 1.0 -2.9            

Definitions

Field Contents SI Unit Example
CID Unique coordinate system identification.
Integer
Specifies an identification number for this coordinate system.
<String>
Specifies a user-defined string label for this coordinate system. 8

(Integer > 0 or <String>)

  
RID Identification number of a reference coordinate system that is defined independently from this coordinate system.7

Default = 0 (Integer ≥ 0)

  
A1, A2, A3, B, B, B, C, C, C Coordinates of three points in the reference coordinate system (RID). If RID is blank or 0, the reference coordinate system is the default basic coordinate system.

(Real)

  


Figure 1. Defining a Spherical Coordinate System (CID) using Grid Points A, B and C

Comments

  1. The three points (A1, A2, A3), (B, B, B), (C, C, C) must be unique and non-collinear. Non-collinearity is checked by the geometry processor.
  2. Coordinate system identification numbers on all CORD1R, CORD1C, CORD1S, CORD2R, CORD2C, CORD2S, CORD3R, and CORD4R entries must all be unique.
  3. A duplicate identification number is allowed if the CID and GID are identical and the coordinates are within the value set by PARAM,DUPTOL.
  4. The location of a grid point (P) in this spherical coordinate system is given by (R, θ, and φ). Where, θ and φ are measured in degrees. See Figure 1.
  5. The displacement coordinate directions at P are (ur, uθ, and uφ). The displacements in all three of these directions at the grid point are specified in units of length. See Figure 1.
  6. Points on the polar axis may not have their displacement directions defined in this coordinate system due to ambiguity.
  7. The reference coordinate system (RID) should be independently defined or left blank. If blank (or 0), the reference coordinate system is the default basic coordinate system. In such cases, A, B and C are defined with respect to the basic coordinate system.
  8. String based labels allow for easier visual identification of coordinate systems, including when being referenced by other cards. Currently, coordinate systems with string IDs can be referenced only by JOINTG elements. For more details, refer to String Label Based Input File in the Bulk Data Input File.
  9. This card is represented as a system in HyperMesh.