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.

Figure 184cyl.1: MPC184 Cylindrical Joint Geometry

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

u_r = 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

Large deflection

Linear perturbation

KEYOPT(1)

Element behavior:

11 --: Cylindrical joint element

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

Constraint stop status:
0 = stop not active, or deactivated
1 = stopped at minimum value
2 = stopped at maximum value
Constraint lock status:
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
Output Quantity Name	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
Output Quantity Name	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.
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 Cylindrical Joint 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.