MPC184-Planar


Multipoint Constraint Element: Planar Joint

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MPC184 Planar Joint Element Description

The MPC184 planar joint element is a two-node element that has two relative displacement degrees of freedom and one relative rotational degree of freedom. All other relative degrees of freedom are fixed.

Figure 184plan.1: MPC184 Planar Joint Geometry

MPC184 Planar Joint Geometry

MPC184 Planar Joint Input Data

Set KEYOPT(1) = 12 to define a two-node planar joint element.

Figure 184plan.1: MPC184 Planar Joint Geometry shows the geometry and node locations for this element. Two nodes (I and J) define the element.

If KEYOPT(4) = 0, the element is an x-axis planar joint element with the local e1 axis as the rotation axis and also the axis along which the distance is fixed.

If KEYOPT(4) = 1, the element is a z-axis planar joint element with the local e3 axis as the rotation axis and also the axis along which the distance is fixed.

A local Cartesian coordinate system must be specified at the first node, I, of the element. The local coordinate system specification at the second node is optional. The local coordinate systems specified at node I and J evolve with the rotations at the respective nodes. Use the SECJOINT command to specify the identifiers of the local coordinate systems.

The constraints imposed on a planar joint element with local e1 axis as the axis of rotation are described below. Similar constraint conditions are set up when the local e3 axis is the axis of rotation. Referring to Figure 184plan.1: MPC184 Planar Joint Geometry, the constraints imposed at any given time are as follows:

The changes in the relative position of the nodes I and J are given by:

The change in the relative angular position between the two local coordinate systems is given by:

ur = ϕ - ϕ0 + mπ

The constitutive calculations use the following definition of the joint displacement:

where:

and = reference lengths, length2 and length3, specified on the SECDATA command.

The constitutive calculations use the following definition of the joint rotation:

where:

= reference angle, angle1, specified on the SECDATA command. If this value is not specified, then ϕ0 is used in place of .

Other input data that are common to all joint elements (material behavior, stops and limits, locks, etc.) are described in "Joint Input Data" in the MPC184 element description.

MPC184 Planar Joint Input Summary

This input summary applies to the planar joint element option of MPC184: KEYOPT(1) = 12.

Nodes

I, J

Note:  For a grounded joint element, specify either node I or node J in the element definition and leave the other node (the grounded node) blank.

Degrees of Freedom

UX, UY, UZ, ROTX, ROTY, ROTZ

Real Constants

None

Material Properties

Use the JOIN label on the TB command to define stiffness and damping behavior. (See MPC184 Joint in the Material Reference for detailed information on defining joint materials.)

Surface Loads

None

Body Loads
Temperatures -- 

T(I), T(J)

Element Loads when KEYOPT(4) = 0
Displacements/Rotations -- 

UY, UZ, ROTX

Velocities -- 

VELY, VELZ, OMGX

Accelerations -- 

ACCY, ACCZ, DMGX

Element Loads when KEYOPT(4) = 1
Displacements/Rotations -- 

UX, UY, ROTZ

Velocities -- 

VELX, VELY, OMGZ

Accelerations -- 

ACCX, ACCY, DMGZ

Special Features
KEYOPT(1)

Element behavior:

12  -- 

Planar joint element

KEYOPT(2)

Element constraint imposition method:

0 -- 

Lagrange multiplier method (default)

1  -- 

Penalty-based method

KEYOPT(4)

Element configuration:

0 -- 

x-axis Planar joint with local 1 direction as the rotation axis.

1  -- 

z-axis Planar joint with local 3 direction as the rotation axis.

MPC184 Planar Joint Output Data

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

These tables use 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 184plan.1: MPC184 Planar Joint Element Output Definitions

NameDefinitionOR
x-axis Planar Joint Element (KEYOPT(4) = 0)
ELElement number-Y
NODESElement node numbers (I, J)-Y
FXConstraint force in X direction-Y
MYConstraint moment in Y direction-Y
MZConstraint moment in Z direction-Y
CSTOP2Constraint force if stop is specified on DOF 2-Y
CSTOP3Constraint force if stop is specified on DOF 3-Y
CSTOP4Constraint moment if stop is specified on DOF 4-Y
CLOCK2Constraint force if lock is specified on DOF 2-Y
CLOCK3Constraint force if lock is specified on DOF 3-Y
CLOCK4Constraint moment if lock is specified on DOF 4-Y
CSST2Constraint stop status on DOF 2[1]-Y
CLST2Constraint lock status on DOF 2[2]-Y
CSST3Constraint stop status on DOF 3[1]-Y
CLST3Constraint lock status on DOF 3[2]-Y
CSST4Constraint stop status on DOF 4[1]-Y
CLST4Constraint lock status on DOF 4[2]-Y
JRP2Joint relative position of DOF 2-Y
JRP3Joint relative position of DOF 3-Y
JRP4Joint relative position of DOF 4-Y
JCD2Joint constitutive displacement on DOF 2-Y
JCD3Joint constitutive displacement on DOF 3-Y
JCD4Joint constitutive rotation on DOF 4-Y
JEF2Joint elastic force in direction -2-Y
JEF3Joint elastic force in direction -3-Y
JEF4Joint elastic moment in direction -4-Y
JDF2Joint damping force in direction -2-Y
JDF3Joint damping force in direction -3-Y
JDF4Joint damping moment in direction -4-Y
JRU2Joint relative displacement of DOF 2-Y
JRU3Joint relative displacement of DOF 3-Y
JRU4Joint relative rotation of DOF 4-Y
JRV2Joint relative velocity of DOF 2-Y
JRV3Joint relative velocity of DOF 3-Y
JRV4Joint relative rotational velocity of DOF 4-Y
JRA2Joint relative acceleration of DOF 2-Y
JRA3Joint relative acceleration of DOF 3-Y
JRA4Joint relative rotational acceleration of DOF 4-Y
JTEMPAverage temperature in the element[3]-Y
z-axis Planar Joint Element (KEYOPT(4) = 1)
ELElement Number-Y
NODESElement node numbers (I, J)-Y
FZConstraint Force in Z direction-Y
MXConstraint Moment in X direction-Y
MYConstraint Moment in Y direction-Y
CSTOP1Constraint force if stop is specified on DOF 1-Y
CSTOP2Constraint force if stop is specified on DOF 2-Y
CSTOP6Constraint moment if stop is specified on DOF 6-Y
CLOCK1Constraint force if lock is specified on DOF 1-Y
CLOCK2Constraint force if lock is specified on DOF 2-Y
CLOCK6Constraint moment if lock is specified on DOF 6-Y
CSST1Constraint stop status on DOF 1[1]-Y
CLST1Constraint lock status on DOF 1[2]-Y
CSST2Constraint stop status on DOF 2[1]-Y
CLST2Constraint lock status on DOF 2[2]-Y
CSST6Constraint stop status on DOF 6[1]-Y
CLST6Constraint lock status on DOF 6[2]-Y
JRP1Joint relative position of DOF 1-Y
JRP2Joint relative position of DOF 2-Y
JRP6Joint relative position of DOF 6-Y
JCD1Joint constitutive displacement on DOF 1-Y
JCD2Joint constitutive displacement on DOF 2-Y
JCD6Joint constitutive rotation on DOF 6-Y
JEF1Joint elastic force in direction -1-Y
JEF2Joint elastic force in direction -2-Y
JEF6Joint elastic moment in direction -6-Y
JDF1Joint damping force in direction -1-Y
JDF2Joint damping force in direction -2-Y
JDF6Joint damping moment in direction -6-Y
JRU1Joint relative displacement of DOF 1-Y
JRU2Joint relative displacement of DOF 2-Y
JRU6Joint relative rotation of DOF 6-Y
JRV1Joint relative velocity of DOF 1-Y
JRV2Joint relative velocity of DOF 2-Y
JRV6Joint relative rotational velocity of DOF 6-Y
JRA1Joint relative acceleration of DOF 1-Y
JRA2Joint relative acceleration of DOF 2-Y
JRA6Joint relative rotational acceleration of DOF 6-Y
JTEMPAverage temperature in the element[3]-Y

  1. Constraint stop status:

    0 = stop not active, or deactivated
    1 = stopped at minimum value
    2 = stopped at maximum value

  2. Constraint lock status:

    0 = lock not active
    1 = locked at minimum value
    2 = locked at maximum value

  3. Average temperature in the element when temperatures are applied on the nodes of the element using the BF command, or when temperature are applied on the element using the BFE command.

The following table shows additional non-summable miscellaneous (NMISC) output available for all forms of the planar joint element.

Note:  This output is intended for use in the Ansys Workbench program to track the evolution of local coordinate systems specified at the nodes of joint elements.

Table 184plan.2: MPC184 Planar Joint Element - NMISC Output

NameDefinitionOR
The following output is available for all planar joint elements (KEYOPT(4) = 0 and 1)
E1X-I, E1Y-I, E1Z-IX, Y, Z components of the evolved e1 axis at node I-Y
E2X-I, E2Y-I, E2Z-IX, Y, Z components of the evolved e2 axis at node I-Y
E3X-I, E3Y-I, E3Z-IX, Y, Z components of the evolved e3 axis at node I-Y
E1X-J, E1Y-J, E1Z-JX, Y, Z components of the evolved e1 axis at node J-Y
E2X-J, E2Y-J, E2Z-JX, Y, Z components of the evolved e2 axis at node J-Y
E3X-J, E3Y-J, E3Z-JX, Y, Z components of the evolved e3 axis at node J-Y
JFX, JFY, JFZConstraint forces expressed in the evolved coordinate system specified at node I-Y
JMX, JMY, JMZConstraint moments expressed in the evolved coordinate system specified at node I-Y

Table 184plan.3: MPC184 Planar Joint Item and Sequence Numbers - SMISC Items and Table 184plan.4: MPC184 Planar Joint Item and Sequence Numbers - NMISC Items list 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

Table 184plan.3: MPC184 Planar Joint Item and Sequence Numbers - SMISC Items

Output Quantity Name ETABLE and ESOL Command Input
ItemE
x-axis Planar Joint Element (KEYOPT(4) = 0)
FXSMISC1
MYSMISC5
MZSMISC6
CSTOP2SMISC8
CSTOP3SMISC9
CSTOP4SMISC10
CLOCK2SMISC14
CLOCK3SMISC15
CLOCK4SMISC16
CSST2SMISC20
CSST3SMISC21
CSST4SMISC22
CLST2SMISC26
CLST3SMISC27
CLST4SMISC28
JRP2SMISC32
JRP3SMISC33
JRP4SMISC34
JCD2SMISC38
JCD3SMISC39
JCD4SMISC40
JEF2SMISC44
JEF3SMISC45
JEF4SMISC46
JDF2SMISC50
JDF3SMISC51
JDF4SMISC52
JRU2SMISC62
JRU3SMISC63
JRU4SMISC64
JRV2SMISC68
JRV3SMISC69
JRV4SMISC70
JRA2SMISC74
JRA3SMISC75
JRA4SMISC76
JTEMPSMISC79
z-axis Planar Joint Element (KEYOPT(4) = 1)
FZSMISC3
MXSMISC4
MYSMISC5
CSTOP1SMISC7
CSTOP2SMISC8
CSTOP6SMISC12
CLOCK1SMISC13
CLOCK2SMISC14
CLOCK6SMISC18
CSST1SMISC19
CSST2SMISC20
CSST6SMISC24
CLST1SMISC25
CLST2SMISC26
CLST6SMISC30
JRP1SMISC31
JRP2SMISC32
JRP6SMISC36
JCD1SMISC37
JCD2SMISC38
JCD6SMISC42
JEF1SMISC43
JEF2SMISC44
JEF6SMISC48
JDF1SMISC49
JDF2SMISC50
JDF6SMISC54
JRU1SMISC61
JRU2SMISC62
JRU6SMISC66
JRV1SMISC67
JRV2SMISC68
JRV6SMISC72
JRA1SMISC73
JRA2SMISC74
JRA6SMISC78
JTEMPSMISC79

Table 184plan.4: MPC184 Planar Joint Item and Sequence Numbers - NMISC Items

Output Quantity Name ETABLE and ESOL Command Input
ItemE
The following output is available for all planar joint elements (KEYOPT(4) = 0 and 1)
E1X-INMISC1
E1Y-INMISC2
E1Z-INMISC3
E2X-INMISC4
E2Y-INMISC5
E2Z-INMISC6
E3X-INMISC7
E3Y-INMISC8
E3Z-INMISC9
E1X-JNMISC10
E1Y-JNMISC11
E1Z-JNMISC12
E2X-JNMISC13
E2Y-JNMISC14
E2Z-JNMISC15
E3X-JNMISC16
E3Y-JNMISC17
E3Z-JNMISC18
JFXNMISC19
JFYNMISC20
JFZNMISC21
JMXNMISC22
JMYNMISC23
JMZNMISC24

MPC184 Planar Joint Assumptions and Restrictions

  • Boundary conditions cannot be applied on the nodes forming the planar joint.

  • Rotational degrees of freedom are activated at the nodes forming the element. When these elements are used in conjunction with solid elements, the rotational degrees of freedom must be suitably constrained. Since boundary conditions cannot be applied to the nodes of the planar joint, a beam or shell element with very weak stiffness may be used with the underlying solid elements at the nodes forming the joint element to avoid any rigid body modes.

  • If both stops and locks are specified, then lock specification takes precedence. That is, if the degree of freedom is locked at a given value, then it will remain locked for the rest of the analysis.

  • In a nonlinear analysis, the components of relative motion are accumulated over all the substeps. It is essential that the substep size be restricted such that these rotations in a given substep are less than π for the values to be accumulated correctly.

  • The element currently does not support birth or death options.

  • The equation solver (EQSLV) must be the sparse solver.

  • For the Lagrange multiplier element formulation (KEYOPT(2) = 0), the equation solver (EQSLV) must be the sparse solver. Either the sparse or the PCG solver can be used with penalty-based element formulation (KEYOPT(2)=1).

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

MPC184 Planar Joint Product Restrictions

None.