CLRNC

Bulk Data Entry Defines parameters for clearance and threaded bolts geometry.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CLRNC ID
BOLT ALPHA PITCH DMAJOR DMEAN NSTART HANDED
GSET_1 CLEARANCE XA YA ZA XB YB ZB
etc.
GSET_n CLEARANCE XA YA ZA XB YB ZB

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CLRNC 102
BOLT 20.0 1.5 10.0
33 0.0 0.0 0.0 0.0 2.0 0.0

Definitions

Field Contents SI Unit Example
ID Each CLRNC Bulk Data Entry should have a unique ID.

No default (Integer > 0)

BOLT Continuation lines for thread bolt definition flag.
ALPHA Half pitch angle. 5

No default (Real)

PITCH Pitch, $p$ . 5

Pitch is the distance from the crest of one thread to the next.

No default (Real)

DMAJOR Bolt major thread diameter, $d$ . 5

No default - See Comment 3 (Real)

DMEAN Bolt mean thread diameter, ${d}_{m}$ . 5

No default - See Comment 3 (Real)

NSTART Number of starts. The number of starts influences the Lead of the bolt. The Lead is the distance along the bolt axis that is covered by one complete rotation (360 degrees). Lead = NSTART*PITCH.

Default = 1 (Integer > 0)

HANDED Handedness option.
RIGHT (Default)
Right handed.
LEFT
Left handed.
blank

GSET_i Grid set ID from the secondary surface, where threading is to be defined. 4 5 8

No default (Integer)

CLEARANCE Initial gap opening between main and secondary, irrespective of the actual distance between the nodes.

Default = blank (Real or blank)

XA, YA, ZA Coordinates of Point A, which is used to define vector AB. 6

No default (Real)

XB, YB, ZB Coordinates of Point B, which is used to define vector AB. 6

No default (Real)

1. The CLRNC Bulk Data Entry is selected on the CLEARANCE field in the CONTACT or PCONT Bulk Data Entry. If the definitions conflict, then the ID defined on PCONT takes precedence.
2. In each CLRNC card, only one set of bolt geometry can be defined. The bolts with this geometry can be in multiple locations in a model. The location and orientation of each bolt are defined in the continuation lines of GSET_i and coordinates of Point A and B.
3. Either DMAJOR or DMEAN should be provided. When both are input, DMEAN is used and DMAJOR is ignored. When DMEAN is blank, the mean diameter of the bolt is calculated as: (1)
${d}_{m}=d-0.649519*p$
Where,
$d$
Major diameter.
$p$
Pitch of the bolt.
4. The grids included in GSET_i are considered as threaded, if they are from the secondary side of a contact. A particular grid point should be included in one GSET_i only. It is not meaningful to include the same grid point in multiple GSET_i sets, as that implies that the same grid point is part of different threads.
5. GSET_i should be a subset of the set of grids belonging to the corresponding secondary contact. It is your responsibility to make sure that the GSET_i does not contain unexpected grids.
6. Points A (XA, YA, ZA) and B (XB, YB, ZB) are two points located on the bolt axis. They can be defined at any location on the bolt axis. They cannot be coincident points. A and B are just two points which define the bolt axis, and do not define any direction of the bolt. The lead direction (direction of tightening) of the bolt axis based on the HANDED field.
7. It is not required for the bolt and nut mesh to be conforming to each other.
8. Multiple GSET_i continuation lines can be defined on a single CLRNC entry. This allows modeling multiple bolts with a single threaded bolt geometry. As long as these multiple GSET_i individually contain grids belonging to secondary sides of separate contact interfaces, then all these contact interfaces are applied the same threaded bolt geometry.
9. Friction is optional and can be defined on the PCONT entry if required.
10. Typical contact related output such as contact status, contact forces, and so on are available for threaded bolts, as well. Additionally, general outputs such as displacement, stresses, and so on are also available.