The slider element needs two lines connected at one node to work correctly. The lines should be 180 degrees from each other (meaning they make a straight line when combined). The node that connects the two lines together is considered Node 3. Node 1 and Node 2 are decided by the program if they are not specified. You can specify Node 1 or Node 2 by using the surface number of the two lines. Node 1 will be the node on the line that is of the lower surface number and is not the node connecting the two lines together (see below - green represents Surface 1 while red represents Surface 2).
The default options for the slider element are for Node 3 to go along the path created by the two lines. Node 3 will not be constrained to the distance of the lines and will use the equation of these two lines if it needs to go past Node 1 or Node 2.
If another part of the model is to move with the slider element, the part should be connected at node 3 of the slider mechanism. This will allow the other part to follow the path the slider. Also, the constraints for the slider element should be applied to Nodes 1 or 2. No constraints should be applied to node 3.
Slider elements can be attached to beam, truss, brick and 2D elements
Figure 1: Surface Determination of the Node Numbers of a Slider Element
Slider Element Parameters
The Constraints tab of the Element Definition dialog can be used to force the axial and planar rotations of two nodes of the slider element to be identical by activating the appropriate check boxes.
Advanced Slider Element Parameters
The Advanced tab can be used to define the allowable angle between the two lines of the slider element. This angle is always taken as positive. A value of 0 implies that the two lines are parallel but do not overlap. A value of 180 implies that the lines are parallel and do overlap. A large value (about 30) can be used to force 3 noncellular nodes to lie on the same line.
If the Node 3 moves along line that passes through nodes 1 and 2 check box is activated, the motion of Node 3 will be constrained to a line that passes through Nodes 1 and 2. Node 3 does not have to stay in between the two nodes. If your application demand that Node 3 stays in between Nodes 1 and 2, we recommend using contact or coupling elements. There are only rare situations when this check box should be deactivated. Such situations occur when the user wants to simply constrain the axial and/or planar rotations of nodes. The coupling of rotations between two nodes can be done using actuator elements. The slider element can be used to couple the rotations of three nodes.
Basic Steps for Use of Slider Elements
- Be sure that a unit system is defined.
- Be sure that the model is using a nonlinear analysis type.
- Right-click the Element Type heading for the part that you want to be slider elements.
- Select the Slider command.
- Right-click the Element Definition heading.
- Select the Edit Element Definition command.
- Activate the check boxes for the rotations that you want to couple.
- Press the OK button.