This facility may be used to generate nodes by rotating nodes already input by a specified angle about a specified position. This is particularly useful for describing the nodes on axisymmetric bodies.
2 5 7 11 16 21 31 51 61 71
- --- -- ---- ----- ----- --------- -- -- --------- --------- -------
R|END| | 101| 3| 100| 20.0 | ... | 0.0 | 0.0 | 30.0...
- --- -- ---- ----- ----- --------- -- -- --------- --------- -------
| | | | | | | | | | | |
| | | | | | |-------- |-----------------------
| | | | | | | |
| | | | | | | _(6)Angular Rotation
| | | | | | | VECTOR(Degrees.3F10.0)
| | | | | | |
| | | | | | |_(5)3 Coordinates for Position about which
| | | | | | to rotate(3F10.0)
| | | | | |
| | | | | |_(4)Increment for Each set of Node Numbers(I5)
| | | | |
| | | | |_(3)Number of Nodal Sets to be Generated(I5)(Default 1)
| | | |
| | | |_(2)The User node number of the 1st node in a set.
| | |
| | |_Optional User Identifier(A2)
| |
| |_Compulsory END on last data record in data category
|
|_(1)Indicates Rotational Node Generation
(1) This single letter code indicates that a set of nodes is to be generated by rotating a set of nodes already input.
(2) This is the starting node of the set to be copied (input sequence = NS1). The finish node of the set is the last node input so far (input sequence = NF1).
(3) This is the number of node sets to be generated (NSETS). The total number of nodes automatically generated in addition to those already input is given by:
Total additional nodes = NSETS (NF1-NS1+1)
If this field is left blank, or zero is input, NSETS=1 is assumed.
(4) This node increment number (N3) is the number by which the node numbers already input are to be incremented. In other words, if the nodes previously input are numbered NP1, NP2, NP3 etc., and the new node numbers are NN1, NN2, NN3 etc., these new node numbers are given by:
NN1 = NP1 + N3; NN2 = NP2 + N3; NN3 = NP3 + N3; etc.
If no increment value is present, or zero is input, the program will issue a warning and default to a value of 100.
(5) These three values are the coordinates of the point about which the rotation of the nodes already input takes place. This field may be left blank, in which case the point is assumed to be 0.0, 0.0, 0.0, i.e. the FRA origin.
(6) These three values (RX,RY,RZ) are the components of the angular vector of rotation, i.e. the angle and axis about which the rotation takes place is given by
Angle = modulus (RX,RY,RZ)
Axis = vector (RX,RY,RZ) / Modulus (RX,RY,RZ)
Although this means that the user has the facility to generate nodes rotated about any axis, the most common usage is as follows (using 30 degrees as an example)
Rotation about X-axis RX = 30.0 RY = 0.0 RZ = 0.0
Rotation about Y-axis RX = 0.0 RY = 30.0 RZ = 0.0
Rotation about Z-axis RX = 0.0 RY = 0.0 RZ = 30.0
EXAMPLE
Generation of nodes for six, 50m tall, 8m diameter cylindrical legs of an axisymmetric semi-submersible at a radius of 75 metres
2 5 7 11 16 21 31 41 51 61 71
- --- -- ---- ----- ----- ------- ------- ------- ------- ------- -------
| | | | 1| 6| 1| 79.0 | 0.0 | 0.0 | 0.0 | 0.0 | 10.0 |
- --- -- ---- ----- ----- ------- ------- ------- ------- ------- -------
|R| | | | 12| 10| 75.0 | 0.0 | 0.0 | 0.0 | 0.0 | 30.0 |
- --- -- ---- ----- ----- ------- ------- ------- ------- ------- -------
|R| | | | 5| 200| 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 60.0 |
- --- -- ---- ----- ----- ------- ------- ------- ------- ------- -------Data Record 1 - Generates six nodal coordinate on a vertical line.
Data Record 2 - Generates 12 additional vertical lines at 30 degree intervals; that is, generates the nodes to define a single cylinder. Note that the last set of nodes (121-126) have the same coordinates as the first set (1-6). This makes the numbering sequential for all 12 faces of the regular dodecagon representing the circular surface and hence facilitates the specification of element topology (Data Category 2).
Data Record 3 - Generates five additional cylinders at 60 degree intervals.
Total number of nodes generated (see columns 11 to 15) is 6 (12+1) (5+1) = 468