The multi-body system must be sufficiently constrained.
All typical types of constraints like joints, gears, couplers, user-defined constraints, and high-pair joints can be defined. High pair joints include point-to-curve, point-to-surface, curve-to-curve, curve-to-surface, and surface-to-surface constraints. They can connect rigid bodies, flexible bodies, or a rigid and flexbody.
Before running the solver, OptiStruct removes any redundant constraints in the model. Since the constraint forces associated with redundant constraints are set to be zero, it is important to review all of the constraints in the model to make sure they are physically meaningful and that there are no unintended redundant constraints.
Joints connect two grid points that belong to a body. They constrain the motion between the bodies. They are defined using the JOINT or JOINTM bulk data entries. SPC boundary conditions are automatically translated into the proper joints and connected to the ground body.
|
Fixed |
3 |
3 |
2 |
|
3 |
2 |
3 | |
|
2 |
3 |
3 | |
|
2 |
2 |
3 | |
|
3 |
1 |
4 | |
|
1 |
2 |
3 | |
|
3 |
0 |
2 | |
|
Perpendicular |
0 |
1 |
4 |
|
Parallel axes |
0 |
2 |
4 |
|
Orientation |
0 |
3 |
2 |
|
In-plane |
1 |
0 |
4 |
|
Inline |
2 |
0 |
3 |
|
3 |
1 |
4 |
Couplers are constraints between the translational and/or the rotational motion of two or three joints. They are defined using the COUPLER bulk data entries.