MPC184-Slider
Multipoint
Constraint Element: Slider
MPC184 Slider Element Description
The MPC184 slider element can be used to model a slider constraint. The element has three nodes with three degrees of freedom (translations in X, Y, and Z) at each node. The slider element imposes a kinematic constraint such that a "dependent" node (I) must always lie on a line joining two other "independent" nodes (J and K). The I node is allowed to slide on the line joining J and K nodes. The kinematic constraints are imposed using the Lagrange multiplier method.
MPC184 Slider Input Data
Set KEYOPT(1) = 3 to define a three-node slider element.
Figure 184slid.1: MPC184 Slider Geometry shows the geometry and node locations for this element. Three nodes (I, J, and K) define the element. The node I is expected to lie initially on the line joining the nodes J and K.
Material stiffness properties are not required for this element. The element currently does not support birth or death options.
MPC184 Slider Input Summary
This input summary applies to the slider element option of MPC184: KEYOPT(1) = 3.
- Nodes
I, J, K
- Degrees of Freedom
UX, UY, UZ
- Real Constants
None
- Material Properties
None
- Surface Loads
None
- Body Loads
None
- Element Loads
None
- Special Features
- KEYOPT(1)
Element behavior:
- 3 --
Slider element
- KEYOPT(2)
Element constraint imposition method:
- 0 --
Lagrange multiplier method (default)
- 1 --
Penalty-based method
MPC184 Slider Output Data
The solution output associated with the element is in two forms:
Nodal displacements included in the overall nodal solution
Additional element output as shown in Table 184slid.1: MPC184 Slider Element Output Definitions.
Table 184slid.1: MPC184 Slider Element Output Definitions uses the following notation:
A colon (:) in the Name column indicates the item can be accessed by the Component Name method (ETABLE, ESOL). The O column indicates the availability of the items in the file Jobname.out. The R column indicates the availability of the items in the results file.
In either the O or R columns, Y indicates that the item is always available, a number refers to a table footnote that describes when the item is conditionally available, and a - indicates that the item is not available.
Table 184slid.1: MPC184 Slider Element Output Definitions
| Name | Definition | O | R |
|---|---|---|---|
| EL | Element Number | - | Y |
| NODES | Element node numbers (I, J, K) | - | Y |
| FY | Constraint Force 1 | - | Y |
| FZ | Constraint Force 2 | - | Y |
Table 184slid.2: MPC184 Slider Item and Sequence Numbers lists output available via the ETABLE command using the Sequence Number method. See The General Postprocessor (POST1) in the Basic Analysis Guide and The Item and Sequence Number Table for further information. The table uses the following notation:
- Name
output quantity as defined in the Element Output Definitions table.
- Item
predetermined Item label for ETABLE command
- E
sequence number for single-valued or constant element data
MPC184 Slider Assumptions and Restrictions
The distance between nodes I and J must be greater than zero.
Node I must initially lie between the J and K nodes.
Displacement boundary conditions cannot be applied on the nodes forming the slider element.
The element currently does not support birth or death options.
For the Lagrange multiplier element formulation (KEYOPT(2) = 0) and the penalty-based element formulation (KEYOPT(2) = 1), the equation solver (EQSLV) must be the sparse or the PCG solver.
Lagrange multiplier-based joint elements (KEYOPT(2) = 0) and penalty-based joint elements (KEYOPT(2) = 1) cannot be connected to each other.
The element coordinate system (/PSYMB,ESYS) is not relevant.