2024-01-09 18:01:28 +00:00
|
|
|
# 2D Problem Definition Version 1 (PD2v1) Specification
|
|
|
|
|
|
2024-01-09 18:03:21 +00:00
|
|
|
A format for defining shapes that humans can write and machines can read.
|
2024-01-09 18:01:28 +00:00
|
|
|
|
|
|
|
|
I think it should have a better name.
|
|
|
|
|
|
|
|
|
|
## Usage
|
|
|
|
|
|
|
|
|
|
### Beam Elements (BE)
|
|
|
|
|
|
|
|
|
|
Beam element problem definitions use points to represent nodes and links to represent
|
|
|
|
|
beams.
|
|
|
|
|
|
|
|
|
|
A given point (node) can be connected to any number of links (beams).
|
|
|
|
|
|
|
|
|
|
### Finite Elements (FE)
|
|
|
|
|
|
|
|
|
|
Finite element problem definitions use points to represent nodes and links to represent
|
|
|
|
|
edges.
|
|
|
|
|
|
|
|
|
|
A given point (node) can only be connected to two links (edges).
|
|
|
|
|
|
|
|
|
|
### Mesh
|
|
|
|
|
|
|
|
|
|
The spec can also be used to export meshes by using fixed boundary conditions and definining a set
|
|
|
|
|
of `LINK_PROPS` that can be ignored (i.e. `LINK_PROPS ignore 0 0`).
|
|
|
|
|
|
|
|
|
|
## Types
|
|
|
|
|
|
|
|
|
|
### REAL
|
|
|
|
|
|
|
|
|
|
A real number
|
|
|
|
|
|
|
|
|
|
#### Examples
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
0
|
|
|
|
|
-1
|
|
|
|
|
1
|
|
|
|
|
-1.0
|
|
|
|
|
1.0
|
|
|
|
|
9999999.999999
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
### IDs (`ID`)
|
|
|
|
|
|
|
|
|
|
String that can include numbers, letters, underscores (`_`), and dashes (`-`).
|
|
|
|
|
|
|
|
|
|
### Boundary condition types (`BC_TYPE`)
|
|
|
|
|
|
|
|
|
|
- `NONE`
|
|
|
|
|
- `FIXED`
|
|
|
|
|
- `FORCE <VEC_ID>`
|
|
|
|
|
|
|
|
|
|
## Syntax
|
|
|
|
|
|
|
|
|
|
### Comments
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
// comments begin with // and end at the end of a line
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
### Definitions
|
|
|
|
|
|
|
|
|
|
Each definiton goes on its own line.
|
|
|
|
|
Definitons cannot refer to IDs of objects that are defined in latter lines.
|
|
|
|
|
|
|
|
|
|
Every ID given for every object must be unqiue amongst its object type but not between types (although it is fine if it is).
|
|
|
|
|
All definitions are immutable.
|
|
|
|
|
|
|
|
|
|
| Object Type | Syntax |
|
|
|
|
|
|--------------------|----------------------------------------------------------|
|
|
|
|
|
| Boundary Condition | `BOUNDARY_CONDITION <ID ID> <BC_TYPE BC_TYPE>` |
|
|
|
|
|
| Link | `LINK <ID ID> <ID LINK_PROPS> <ID NODE_ID> <ID NODE_ID>` |
|
|
|
|
|
| Link Properties | `LINK_PROPS <ID ID> <ID MATERIAL> <REAL AREA>` |
|
|
|
|
|
| Material | `MATERIAL <ID ID> <REAL YOUNGS_MODULUS>` |
|
|
|
|
|
| Point | `POINT <ID ID> <ID VEC_ID> <ID BOUNDARY_CONDITION>` |
|
|
|
|
|
| Vector | `VEC <ID ID> <REAL X> <REAL Y>` |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
## Example
|
|
|
|
|
|
|
|
|
|
### Beam Element
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
// Define a fixed boundary conditon as it can be shared by all fixed points
|
|
|
|
|
BOUNDARY_CONDITION bc_fixed FIXED
|
|
|
|
|
MATERIAL aluminium 210000000000 250000000
|
|
|
|
|
LINK_PROPS beam_props aluminium 0.0019635
|
|
|
|
|
|
|
|
|
|
// Define the first node
|
|
|
|
|
VEC point1_pos 0 0
|
|
|
|
|
POINT point1 point1_pos bc_fixed
|
|
|
|
|
|
|
|
|
|
// Define node with force boundary condition
|
|
|
|
|
VEC point4_pos 1.7321 1
|
|
|
|
|
VEC bc4_mag 14142 14142
|
|
|
|
|
BOUNDARY_CONDITION bc4 FORCE bc4_mag
|
|
|
|
|
POINT point4 point4_pos bc4
|
|
|
|
|
|
|
|
|
|
// Define rest of the nodes
|
|
|
|
|
VEC point2_pos 0 1.1547
|
|
|
|
|
POINT point2 point2_pos bc_fixed
|
|
|
|
|
VEC point3_pos 0 4.4641
|
|
|
|
|
POINT point3 point3_pos bc_fixed
|
|
|
|
|
|
|
|
|
|
// And finally link the nodes together to create the beams
|
|
|
|
|
LINK link1 beam_props point1 point4
|
|
|
|
|
LINK link2 beam_props point2 point4
|
|
|
|
|
LINK link3 beam_props point3 point4
|
|
|
|
|
```
|
