Multipoint Constraint Element: Slider

Compatible Products: – | Pro | Premium | Enterprise | Ent PP | Ent Solver | –

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.

Figure 184slid.1:  MPC184 Slider Geometry

MPC184 Slider Geometry

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.


I, J, K

Degrees of Freedom


Real Constants


Material Properties


Surface Loads


Body Loads


Element Loads


Special Features
Large deflection
Linear perturbation

Element behavior:

3  -- 

Slider element

MPC184 Slider Output Data

The solution output associated with the element is in two forms:

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

ELElement Number-Y
NODESElement node numbers (I, J, K)-Y
FYConstraint Force 1-Y
FZConstraint 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:


output quantity as defined in the Element Output Definitions table.


predetermined Item label for ETABLE command


sequence number for single-valued or constant element data

Table 184slid.2:  MPC184 Slider Item and Sequence Numbers

Output Quantity NameETABLE and ESOL Command Input

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.

  • The equation solver (EQSLV) must be the sparse solver or the PCG solver. The command PCGOPT,,,,,,,ON is also required in order to use the PCG solver.

  • The element coordinate system (/PSYMB,ESYS) is not relevant.

MPC184 Slider Product Restrictions

When used in the product(s) listed below, the stated product-specific restrictions apply to this element in addition to the general assumptions and restrictions given in the previous section.

ANSYS Mechanical Pro 

  • Linear perturbation is not available.

Release 18.2 - © ANSYS, Inc. All rights reserved.