MPC184-Cylindrical
Multipoint
Constraint Element: Cylindrical Joint
MPC184 Cylindrical Joint Element Description
The MPC184 cylindrical joint element is a two-node element that has one free relative displacement degree of freedom and one free relative rotational degree of freedom (around the cylindrical or revolute axis). All other relative degrees of freedom are fixed.
MPC184 Cylindrical Joint Input Data
Set KEYOPT(1) = 11 to define a two-node cylindrical joint element.
Figure 184cyl.1: MPC184 Cylindrical Joint Geometry shows the geometry and node locations for this element. Two nodes (I and J) define the element.
If KEYOPT(4) = 0, then the element is an x-axis cylindrical joint element with the local e1 axis as the cylindrical or revolute axis. Translational motion along this axis is also allowed.
If KEYOPT(4) = 1, then the element is a z-axis cylindrical joint element with the local e3 axis as the cylindrical or revolute axis. Translational motion along this axis is also allowed.
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 in a cylindrical joint element with local e1 axis as the cylindrical or revolute axis are described below. Similar constraint conditions are set up when the local e3 axis is the cylindrical or revolute axis. Referring to Figure 184cyl.1: MPC184 Cylindrical Joint Geometry, with local coordinate systems specified at nodes I and J, the constraints imposed at any given time are as follows:
The change in the relative position of the nodes I and J is given by:
where:
|
The relative rotation between nodes I and J is given by:
The change in the relative angular position between the two local coordinate systems is given by
ur = ϕ - ϕ0 + mπ
where ϕ0 is the initial angular offset between the two coordinate systems and m is an integer accounting for multiple rotations about the cylindrical axis.
The constitutive calculations use the following definition of the joint displacement:
where:
 = reference length
specified on 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 Cylindrical Joint Input Summary
This input summary applies to the cylindrical joint element option of MPC184: KEYOPT(1) = 11.
- 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 --
UX, ROTX
- Velocities --
VELX, OMGX
- Accelerations --
ACCX, DMGX
- Force/Moments --
FX, MX
- Element Loads when KEYOPT(4) = 1:
- Displacements/Rotations --
UZ, ROTZ
- Velocities --
VELZ, OMGZ
- Accelerations --
ACCZ, DMGZ
- Force/Moments --
FZ, MZ
- Special Features
- KEYOPT(1)
Element behavior:
- 11 --
Cylindrical joint element
- KEYOPT(2)
Element constraint imposition method:
- 0 --
Lagrange multiplier method (default)
- 1 --
Penalty-based method
- KEYOPT(4)
Element configuration:
- 0 --
x-axis Cylindrical joint with local 1 direction as the cylindrical axis.
- 1 --
z-axis Cylindrical joint with local 3 direction as the cylindrical axis.
MPC184 Cylindrical Joint 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 184cyl.1: MPC184 Cylindrical Joint Element Output Definitions and Table 184cyl.2: MPC184 Cylindrical Joint Element - NMISC Output.
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 184cyl.1: MPC184 Cylindrical Joint Element Output Definitions
| Name | Definition | O | R |
|---|---|---|---|
| x-axis Cylindrical Joint Element (KEYOPT(4) = 0) | |||
| EL | Element Number | - | Y |
| NODES | Element node numbers (I, J) | - | Y |
| FY | Constraint Force in Y direction | - | Y |
| FZ | Constraint Force in Z direction | - | Y |
| MY | Constraint Moment in Y direction | - | Y |
| MZ | Constraint Moment in Z direction | - | Y |
| CSTOP1 | Constraint force if stop is specified on DOF 1 | - | Y |
| CSTOP4 | Constraint moment if stop is specified on DOF 4 | - | Y |
| CLOCK1 | Constraint force if lock is specified on DOF 1 | - | Y |
| CLOCK4 | Constraint moment if lock is specified on DOF 4 | - | Y |
| CSST1 | Constraint stop status on DOF 1[1] | - | Y |
| CLST1 | Constraint lock status on DOF 1[2] | - | Y |
| CSST4 | Constraint stop status on DOF 4[1] | - | Y |
| CLST4 | Constraint lock status on DOF 4[2] | - | Y |
| JRP1 | Joint relative position of DOF 1 | - | Y |
| JRP4 | Joint relative position of DOF 4 | - | Y |
| JCD1 | Joint constitutive displacement on DOF 1 | - | Y |
| JCD4 | Joint constitutive rotation on DOF 4 | - | Y |
| JEF1 | Joint elastic force in direction -1 | - | Y |
| JEF4 | Joint elastic moment in direction -4 | - | Y |
| JDF1 | Joint damping force in direction -1 | - | Y |
| JDF4 | Joint damping moment in direction -4 | - | Y |
| JRU1 | Joint relative displacement of DOF 1 | - | Y |
| JRU4 | Joint relative rotation of DOF 4 | - | Y |
| JRV1 | Joint relative velocity of DOF 1 | - | Y |
| JRV4 | Joint relative rotational velocity of DOF 4 | - | Y |
| JRA1 | Joint relative acceleration of DOF 1 | - | Y |
| JRA4 | Joint relative rotational acceleration of DOF 4 | - | Y |
| JTEMP | Average temperature in the element[3] | - | Y |
| z-axis Cylindrical Joint Element (KEYOPT(4) = 1) | |||
| EL | Element Number | - | Y |
| NODES | Element node numbers (I, J) | - | Y |
| FX | Constraint Force in X direction | - | Y |
| FY | Constraint Force in Y direction | - | Y |
| MX | Constraint Moment in X direction | - | Y |
| MY | Constraint Moment in Y direction | - | Y |
| CSTOP3 | Constraint force if stop is specified on DOF 3 | - | Y |
| CSTOP6 | Constraint moment if stop is specified on DOF 6 | - | Y |
| CLOCK3 | Constraint force if lock is specified on DOF 3 | - | Y |
| CLOCK6 | Constraint moment if lock is specified on DOF 6 | - | Y |
| CSST3 | Constraint stop status on DOF 3[1] | - | Y |
| CLST3 | Constraint lock status on DOF 3[2] | - | Y |
| CSST6 | Constraint stop status on DOF 6[1] | - | Y |
| CLST6 | Constraint lock status on DOF 6[2] | - | Y |
| JRP3 | Joint relative position of DOF 3 | - | Y |
| JRP6 | Joint relative position of DOF 6 | - | Y |
| JCD3 | Joint constitutive displacement on DOF 3 | - | Y |
| JCD6 | Joint constitutive rotation on DOF 6 | - | Y |
| JEF3 | Joint elastic force in direction -3 | - | Y |
| JEF6 | Joint elastic moment in direction -6 | - | Y |
| JDF3 | Joint damping force in direction -3 | - | Y |
| JDF6 | Joint damping moment in direction -6 | - | Y |
| JRU3 | Joint relative displacement of DOF 3 | - | Y |
| JRU6 | Joint relative rotation of DOF 6 | - | Y |
| JRV3 | Joint relative velocity of DOF 3 | - | Y |
| JRV6 | Joint relative rotational velocity of DOF 6 | - | Y |
| JRA3 | Joint relative acceleration of DOF 3 | - | Y |
| JRA6 | Joint relative rotational acceleration of DOF 6 | - | Y |
| JTEMP | Average temperature in the element[3] | - | Y |
0 = stop not active, or deactivated 1 = stopped at minimum value 2 = stopped at maximum value 0 = lock not active 1 = locked at minimum value 2 = locked at maximum value 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 cylindrical 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 184cyl.2: MPC184 Cylindrical Joint Element - NMISC Output
| Name | Definition | O | R |
|---|---|---|---|
| The following output is available for all cylindrical joint elements (KEYOPT(4) = 0 and 1) | |||
| E1X-I, E1Y-I, E1Z-I | X, Y, Z components of the evolved e1 axis at node I | - | Y |
| E2X-I, E2Y-I, E2Z-I | X, Y, Z components of the evolved e2 axis at node I | - | Y |
| E3X-I, E3Y-I, E3Z-I | X, Y, Z components of the evolved e3 axis at node I | - | Y |
| E1X-J, E1Y-J, E1Z-J | X, Y, Z components of the evolved e1 axis at node J | - | Y |
| E2X-J, E2Y-J, E2Z-J | X, Y, Z components of the evolved e2 axis at node J | - | Y |
| E3X-J, E3Y-J, E3Z-J | X, Y, Z components of the evolved e3 axis at node J | - | Y |
| JFX, JFY, JFZ | Constraint forces expressed in the evolved coordinate system specified at node I | - | Y |
| JMX, JMY, JMZ | Constraint moments expressed in the evolved coordinate system specified at node I | - | Y |
Table 184cyl.3: MPC184 Cylindrical Joint Item and Sequence Numbers - SMISC Items and Table 184cyl.4: MPC184 Cylindrical 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 184cyl.3: MPC184 Cylindrical Joint Item and Sequence Numbers - SMISC Items
| Output Quantity Name | ETABLE and ESOL Command Input | |
|---|---|---|
| Item | E | |
| x-axis Cylindrical Joint Element (KEYOPT(4) = 0) | ||
| FY | SMISC | 2 |
| FZ | SMISC | 3 |
| MY | SMISC | 5 |
| MZ | SMISC | 6 |
| CSTOP1 | SMISC | 7 |
| CSTOP4 | SMISC | 10 |
| CLOCK1 | SMISC | 13 |
| CLOCK4 | SMISC | 16 |
| CSST1 | SMISC | 19 |
| CSST4 | SMISC | 22 |
| CLST1 | SMISC | 25 |
| CLST4 | SMISC | 28 |
| JRP1 | SMISC | 31 |
| JRP4 | SMISC | 34 |
| JCD1 | SMISC | 37 |
| JCD4 | SMISC | 40 |
| JEF1 | SMISC | 43 |
| JEF4 | SMISC | 46 |
| JDF1 | SMISC | 49 |
| JDF4 | SMISC | 52 |
| JRU1 | SMISC | 61 |
| JRU4 | SMISC | 64 |
| JRV1 | SMISC | 67 |
| JRV4 | SMISC | 70 |
| JRA1 | SMISC | 73 |
| JRA4 | SMISC | 76 |
| JTEMP | SMISC | 79 |
| z-axis Cylindrical Joint Element (KEYOPT(4) = 1) | ||
| FX | SMISC | 1 |
| FY | SMISC | 2 |
| MX | SMISC | 4 |
| MY | SMISC | 5 |
| CSTOP3 | SMISC | 9 |
| CSTOP6 | SMISC | 12 |
| CLOCK3 | SMISC | 15 |
| CLOCK6 | SMISC | 18 |
| CSST3 | SMISC | 21 |
| CSST6 | SMISC | 24 |
| CLST3 | SMISC | 27 |
| CLST6 | SMISC | 30 |
| JRP3 | SMISC | 33 |
| JRP6 | SMISC | 36 |
| JCD3 | SMISC | 39 |
| JCD6 | SMISC | 42 |
| JEF3 | SMISC | 45 |
| JEF6 | SMISC | 48 |
| JDF3 | SMISC | 51 |
| JDF6 | SMISC | 54 |
| JRU3 | SMISC | 63 |
| JRU6 | SMISC | 66 |
| JRV3 | SMISC | 69 |
| JRV6 | SMISC | 72 |
| JRA3 | SMISC | 75 |
| JRA6 | SMISC | 78 |
| JTEMP | SMISC | 79 |
Table 184cyl.4: MPC184 Cylindrical Joint Item and Sequence Numbers - NMISC Items
| Output Quantity Name | ETABLE and ESOL Command Input | |
|---|---|---|
| Item | E | |
| The following output is available for all cylindrical joint elements (KEYOPT(4) = 0 and 1) | ||
| E1X-I | NMISC | 1 |
| E1Y-I | NMISC | 2 |
| E1Z-I | NMISC | 3 |
| E2X-I | NMISC | 4 |
| E2Y-I | NMISC | 5 |
| E2Z-I | NMISC | 6 |
| E3X-I | NMISC | 7 |
| E3Y-I | NMISC | 8 |
| E3Z-I | NMISC | 9 |
| E1X-J | NMISC | 10 |
| E1Y-J | NMISC | 11 |
| E1Z-J | NMISC | 12 |
| E2X-J | NMISC | 13 |
| E2Y-J | NMISC | 14 |
| E2Z-J | NMISC | 15 |
| E3X-J | NMISC | 16 |
| E3Y-J | NMISC | 17 |
| E3Z-J | NMISC | 18 |
| JFX | NMISC | 19 |
| JFY | NMISC | 20 |
| JFZ | NMISC | 21 |
| JMX | NMISC | 22 |
| JMY | NMISC | 23 |
| JMZ | NMISC | 24 |
MPC184 Cylindrical Joint Assumptions and Restrictions
Boundary conditions cannot be applied on the nodes forming the cylindrical 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 cylindrical 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.
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.