CONTF

I/O Options and Subcase Information Entry

CONTF – Output Request for Contact Results

Description

The CONTF entry can be used in the I/O Options or Subcase Information sections to request contact results output for all nonlinear analysis subcases or individual nonlinear analysis subcases, respectively.

Format

CONTF (format, type) = option

Type	Options	Description
format	<H3D, OPTI, OP2, blank> Default = blank	H3D:	Results are output in Hyper3D format (.h3d file). See below for type.
		OPTI:	The total contact force, normal contact force, tangential contact force, and contact area results are output to the .cntf file (Comment 5).
		OP2:	Results are output in Nastran output2 format (.op2 file).
		blank:	Results are output in all active formats for which the result is available.

type	<ALL,FORCE, PCONT,FRICT> Default = ALL	ALL:	All available contact results types are output.
		FORCE:	Contact force results are output.
		PCONT:	Pressure-type contact results are output: pressure, open-closed status, contact gap opening and penetration (Comment 2).
		FRICT:	Friction-related results are output: frictional traction, sliding distance, and stick-slip status (Comment 2).

option	<YES, ALL, NO, NONE, SID> Default = ALL	YES, ALL, blank:	Contact results are output for all grid points.
		NO, NONE:	Contact results are not output.
		SID:	If a set ID is given, contact results are output only for grid points listed in that set.

Comments

1.	The CONTF entry is only applicable in nonlinear analysis subcases that are identified by the presence of an NLPARM subcase entry. The specific detailed result types displayed differ slightly between NLSTAT and geometrically nonlinear subcases.

2.	Most of the contact results are real numbers and are self-explanatory. Some results that may require clarification are listed below:

•	Open/Closed status is represented by 0.0 for Open and 1.0 for Closed. On graphical display, intermediate values may appear due to transition from open to closed, across individual elements.

•	Slip/Stick Status is represented by 0.0 for Open, 1.0 for Slip and 2.0 for Stick. On graphical display, intermediate values may appear due to transition of status across individual elements.

•	Sliding Distance represents total sliding distance accumulated while the surfaces are in contact. This may be different than just the difference in displacements between the starting and final position.

•

Frictional traction is output in vector form and scalar form respectively for H3D format. Contact Traction/Tangent Vector (v) contains the components of the friction in the basic coordinate system, while Contact Traction/Tangent(s) contains the components of the friction in the local coordinate system of the contact surface. Friction results are always tangential to the surface, and Contact Normal pressure results are always perpendicular to the surface.

The calculation of contact results on both sides of contact interface involves projections and mappings. Therefore, a perfect match of results between two sides cannot be expected, especially on mismatched meshes. Also, the resolution of different types of results (pressure versus gap opening) differs according to their respective FEA interpolation order. Therefore, such results may appear locally inconsistent, especially on second order meshes and mismatched mesh densities. (Usually pressure and traction will appear smoother than gap opening or penetration.)

Multiple formats are allowed on the same entry, separated by a comma. If a format is not specified, then this output control applies to all formats defined by the OUTPUT command, for which the result is available. Only formats that have been activated by an OUTPUT statement are valid for use on this entry. See Results Output for further information.

5.	Only total contact results for each contact interface are output to the .cntf file. For individual grid based results, use H3D format.

6.	Multiple instances of this entry are allowed; if the instances conflict, the last instance dominates.