CONTACT
Bulk Data Entry Defines a contact interface.
Format
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| CONTACT | CTID | PID/ TYPE /MU1 |
SSID | MSID | MORIENT | SRCHDIS | ADJUST | CLEARANCE | |
| DISCRET | TRACK | CORNER | ROT | SORIENT |
The following continuation line is used to define surface smoothing for the contact
interface. It can be repeated as required.
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| + | SMOOTH | SMSIDE | SMREG |
The following continuation line is used to define surface properties which can be
used to trigger edge to edge contact.
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| + | PSURF | PSID1 | PSID2 |
The following continuation line is used to define cohesive material property for
cohesive zone contact.
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| + | COHE | MCOHEDID | COHEGSET |
Example 1
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| CONTACT | 5 | SLIDE | 7 | 8 | |||||
| N2S |
Example 2
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| CONTACT | 5 | SLIDE | 7 | 8 | |||||
| S2S | |||||||||
| SMOOTH | SLAVE | 71 | |||||||
| SMOOTH | SLAVE | 72 | |||||||
| SMOOTH | MASTER | ALL |
Definitions
| Field | Contents | SI Unit Example |
|---|---|---|
| CTID | Contact interface
identification number. (Integer > 0) |
|
| PID | Property identification
number of a PCONT or PCONTX entry. (Integer > 0) |
|
| TYPE | Choose type of contact
without pointing to contact property - respective default property
settings will be used. Default settings can be changed using CONTPRM. 4
|
|
| MU1 | Coefficient of static
friction (
). 5 (0.0 ≤ Real < 1.0) |
|
| SSID | Slave entity
identification number. 1
2 (Integer > 0) |
|
| MSID | Master entity
identification number. 1
3 (Integer > 0) |
|
| MORIENT | Orientation of contact
"pushout" force from master surface. Applies only to masters that
consist of shell elements or patches of grids. Masters defined on
solid elements always push outwards irrespective of this flag. 6
|
|
| SRCHDIS | Search distance criterion
for creating contact condition. When specified, only slave nodes
that are within SRCHDIS distance from master
surface will have contact condition checked. 6 Default = Twice the average edge length on the master surface. For FREEZE contact, half the average edge length. (Real > 0 or blank) For Node-to-Node (N2N) discretization, the default is 0.0 |
|
| ADJUST | Adjustment of slave nodes
onto the master surface at the start of a simulation. 6
For Node-to-Node (N2N) discretization, the default is NO and Real value can be specified for the depth criterion, similar to other discretization types. AUTO and Integer do not apply for N2N discretization. |
|
| CLEARANCE | Initial gap opening
between master and slave, irrespective of the actual distance
between the nodes. 6 Default = blank (Real or blank) |
|
| DISCRET | Discretization approach
type for the construction of contact elements. 1
|
|
| TRACK | Activates Finite-Sliding
contact. 10
|
|
| CORNER | Corner treatment for the
slave surface of S2S contact. 12
|
|
| ROT | Constraining rotational
DOFs for N2S freeze contact with large displacement.
|
|
| SORIENT | Orientation of contact
force applied on the slave surface (which should be in the same
direction as the pushout force from the master surface). This field
is only applicable to S2S contact with CONSLI.
|
|
| SMOOTH | Continuation lines for surface smoothing definition flag. 6 | |
| SMSIDE | Master and/or Slave
side(s) of the contact interface to be smoothed. 6
No default |
|
| SMREG | Specifies the region at
the Master/Slave surface to be smoothed. 6
|
|
| PSURF | Continuation line for surface property assignment. Only supported for explicit analysis. | |
| PSID1 | The
PSURF entry ID which is used to define the
slave surface property. No default (Integer > 0) |
|
| PSID2 | The
PSURF entry ID which is used to define the
master surface property. No default (Integer > 0) |
|
| COHE | Continuation line for cohesive material. 17 | |
| MCOHEDID | Identification number of
MCOHED card that is referenced by the current
contact. No default (Integer > 0) |
|
| COHEGSET | Cohered grid set. 14
|
Comments
- A general set of guidelines for
slave/master selection are:
- Select the surface with finer mesh as the slave and the other as the master.
- Select the smaller surface as the slave and the other as the master.
- Select the softer surface as the slave and the other as the master.
For information regarding choosing between N2S and S2S contact, refer to Contact Discretization in the User Guide.
- The slave entity
(SSID) always consists of grid nodes. It may be specified
as:
- A set of grid nodes defined using SET(GRID, ..) command
- A surface defined using SURF command (the slave nodes are picked from the respective nodes of the SURF faces)
- A set of elements (shells or solids) defined using SET(ELEM, ..) command. Slave nodes are picked from the respective nodes of the elements in the set. For 3D solids, only nodes on the surface of the solid body are selected; internal nodes are not considered.
DISCRET=N2S is recommended if the slave entity is a set of grids (nodes) or a set of solid elements.
- The master entity
(MSID) may be defined as:
- A surface defined using SURF command.
- A set of elements (shells or solids) defined using SET(ELEM, ..) command. For sets of 3D solids, element faces on the surface are automatically found and selected as master surface.
- The MSID can be left blank or set the same as SSID to activate Self Contact condition. This is currently supported only for Node-to-Surface (N2S) and Surface-to-Surface (S2S) contact with Continuous Sliding (CONSLI). For further information, refer to Self-Contact in the User Guide.
- For N2N discretization, MSID should refer to a GRID set defined by the SET entry.
- For information on the different contact interfaces (TYPE field options), refer to Contact Interface Types in the User Guide.
- MU1 directly on the
CONTACT card allows for simplified specification of
frictional contacts.Note: This implies MU2=MU1, unless MU2 is specified explicitly on the CONTPRM card. Also, the value of MU1 assigned on the CONTACT card must be less than 1.0 - to specify higher values of static coefficient of friction, the PCONT card must be used.
If FRIC is not explicitly defined on the PCONTX/PCNTX# entries, the MU1 value on the CONTACT or PCONT entry is used for FRIC in the /INTER entries for Explicit Dynamic Analysis. Otherwise, FRIC on PCONTX/PCNTX# overwrites the MU1 value on CONTACT/PCONT. For further information regarding frictional contact, refer to Friction in the User Guide.
- For information regarding the different contact parameters (ADJUST, CLEARANCE, MORIENT, TRACK, SMOOTH, SRCHDIS, GPAD), refer to Contact Interface Parameters (Contact Control) in the User Guide.
- Contact stabilization for Surface-to-Surface Contact and Node-to-Surface contact can be activated using the CNTSTB Subcase Information and CNTSTB Bulk Data Entries. Additionally, PARAM, EXPERTNL,CNTSTB can be used to activate contact stabilization. The CNTSTB Bulk Data parameters override the parameter values for a particular subcase.
- Thermal-structural analysis problems involving contact are fully coupled since contact status changes thermal conductivity. For further information, refer to Contact-based Thermal Analysis in the User Guide.
- Applying rotational SPC on nodes which belong to a FREEZE contact should be avoided. Fixing the rotational degrees of freedom will prevent the rotation of these contact nodes even in the case of solid elements.
- Finite Sliding (TRACK=FINITE) option is currently supported only if TYPE=SLIDE or if friction (via MU1/CONTPRM/PCONT) is defined. For further information, refer to Finite Sliding (TRACK) in the User Guide.
- In continuous-sliding contact (TRACK=CONSLI), the contact search is conducted for every contact iteration. In the formulation of contact virtual work, every term is updated based on the status in current iteration. The contact tangent stiffness matrix is computed in a consistent way. Continuous-sliding contact is expected to produce more accurate results and in some cases, better convergence robustness, especially when very large sliding and/or distortion are present.
- Corner treatment is supported for S2S contact. When corner treatment is turned on (AUTO or Real value), the contact surface around a slave node may be divided into several continuous surface patches if break angle criteria are satisfied on one or more edges at the node. For each surface patch, a separate contact element will be created for the element stiffness matrix, element force vector and element history variables computation. Corner treatment may improve robustness and accuracy in some cases.
- The CONTACT entry
is supported for:
- Linear and Nonlinear Static Analysis
- Linear and Nonlinear Transient Analysis
- Linear Dynamic Analysis
- Heat Transfer Analysis
- Contact-based Thermal Analysis (HEAT)
- Explicit Dynamic Analysis (EXPDYN)
CONTACT entry is currently not supported in Flex Body Generation run.
- N2S option should be used to activate large shape change during shape optimization. Currently, large shape change is activated if the model has N2S contact or CGAP/CGAPG/CWELD/CFAST/CSEAM elements.
- N2N discretization is currently only supported for Small Displacement Nonlinear Analysis.
- Axisymmetric and plane-strain
contacts are supported for axisymmetric elements (CQAXI,
CTAXI, and CTRIAX6 elements) and
plane-strain solid elements (CQPSTN and
CTPSTN elements). The SURF
entry can be used to define the Master and Slave surfaces. Axisymmetric and plane-strain contacts are currently supported for:
- SMALL (small sliding) for both N2S and S2S discretization
- CONSLI (continuous sliding) for N2S discretization
Axisymmetric and plane-strain contacts are not supported for:- FINITE (finite sliding)
- CONSLI (continuous sliding) for S2S discretization
- Surface Smoothing
- Cohesive contact works only for small-sliding (TRACK=SMALL), frictionless (TYPE=SLIDE or MU1=0.0) N2S/S2S contact.
- This card is represented as a group in HyperMesh.