2 5 7 11 16 21 31 41
- --- -- ---- ----- ----- -----------------------------
|X| | |QPPL| DIFF| |(30)(11,1)(71,1)(72,1)(12,1)
- --- -- ---- ----- ----- -----------------------------
|X| | |TUBE| | |(10)(11,3)(71,3)(2)(1)
- --- -- ---- ----- ----- -----------------------------
|X| | |DISC| | |(1)(11)(71)(1)
- --- -- ---- ----- ----- -----------------------------
| | | | | |
| | | | | |
| | | | | (3)Columns 21-80 free format data for
| | | | | generating NODE,MATERIAL,and GEOMETRIC
| | | | | GROUP NUMBERS. Format(60A1)
| | | | |
| | | | |_(2)Element Group Number(I5)
| | | |
| | | |_(4) DIFF identifier (diffracting plates only)
| | |
| | |_(1)Element Type(A4)
| |
| |_Optional User Identifier(A2)
|
|_Compulsory END on Last Data Record in Data Category(A3)
(1) The element type (always four characters) provides the classification for a particular element, i.e. the number of nodes, and whether material and geometric properties are required. Valid codes for element types are QPPL, TPPL, TUBE, PMAS, PBOY, FPNT, DISC and STUB as shown below:
| Description | No of Nodes | Material Property | Geometric Property | |||
| QPPL | Quadrilateral Panel | 4 | none | none | ||
| TPPL | Triangular Panel | 3 | none | none | ||
| TUBE | Tube | 2 | density | geometry | ||
| PMAS | Point Mass | 1 | mass | inertia | ||
| PBOY | Point Buoyancy | 1 | displaced mass | none | ||
| FPNT | Field Point | 1 | none | none | ||
| STUB | Slender Tube | 3 | mass, inertia | geometry | ||
| DISC | Circular Disc | 2 | none | geometry | ||
(2) The element group number associated with each element is used to divide the elements defining the structure into groups. Groups can be used for plotting and to identify special sets of elements (see The ILID Data Record - Suppression of Irregular Frequencies and The VLID Data Record - Suppression of Standing Waves), but the group number may be left blank if desired.
(3) Free Format data generation is achieved by specifying several bracketed sets of Topological variables in columns 21-80. The number of bracketed sets is given by
Number of Sets = 1 + (Number of Nodes)
+ 1 if a Material Group is required
+ 1 if a Geometry Group is required
In general we have a format of
(N)(N1,N2,N3) (N1,N2,N3) (N1,N2,N3).....
- -------- -------- --------
| | |
| | |
first second node third node
node or parameter or parameterN - Number of elements to be generated
N1 - Starting Node number, Material Group number or Geometric Group number
N2 - Increment of N1 for each element generated
N3 - Increment of N2 for each element generated
For the ith element of the N elements generated (whether the set applies to a node number, material or geometric group number) each bracketed set will produce the number
Note:
The nodes defining TPPL and QPPL elements must be ordered in a counterclockwise direction from the perspective of an observer external to the structure.
In an Aqwa-Line data file, QPPL and TPPL elements which are below the still water line in the Aqwa-Line analysis position must be denoted as diffracting elements by entering the identifier DIFF in columns 12 to 15.
For structures which cross the waterline, the top row of diffracting plate elements must have their top edges aligned with the still water line (i.e. diffracting plates must not cross the still water line).