General info for all super elements
What a super element is
A super element is a body that stands for many points at once - the nodes of a finite element mesh, the links of a robot - and computes their motion from its own coordinates.
object |
coordinates |
what it is for |
|---|---|---|
|
the coordinates of its nodes |
a linear or nonlinear system of second order equations: mass, damping and stiffness matrices, user functions |
|
a rigid body node and the nodes of the mesh |
a flexible body in the floating frame of reference formulation, with all mesh coordinates |
|
a rigid body node and a |
the same, reduced to a few modes: the flexible body of choice, imported with |
|
a |
an open tree of rigid links in minimal coordinates, e.g. a serial robot |
Mesh nodes
The points a super element stands for are its mesh nodes, numbered from 0 within the object. A
mesh node may be a node of the system (ObjectGenericODE2, ObjectFFRF) or exist only in the
object and be computed from its coordinates (ObjectFFRFreducedOrder: from the modes). Each mesh
node has output variables of its own - its position, displacement, velocity, and for the FFRF
objects stresses and strains where the modes carry them - which SensorSuperElement measures and
the contour plot draws.
Marker interfaces
Forces, connectors and joints act on a super element through its own markers:
MarkerSuperElementPosition averages the positions of a set of mesh nodes with weights, and
MarkerSuperElementRigid also a rotation, from mesh nodes that can represent a rigid body motion;
the kinematic tree has MarkerKinematicTreeRigid at a link. Their Jacobians are those of the mesh
nodes, weighted. The general body markers act on the FFRF objects’ reference frame only, and not
at all on ObjectGenericODE2 and ObjectKinematicTree, where Assemble() refuses them; the page of
each object says which.
Drawing
A super element is drawn if bodies.show and its own show are True: its triangle mesh
on its nodes, the deformation scaled by bodies.deformationScaleFactor, in its color or bodies.defaultColor;
in a contour plot (contour.outputVariable, contour.outputVariableComponent) colored by the values at the nodes.
bodies.showNumbers writes its number.
The settings: bodies.show, bodies.showNumbers, bodies.defaultColor, bodies.deformationScaleFactor, contour.outputVariable, contour.outputVariableComponent.