Option to be performed. The remaining arguments depend on the value of Option. Possible options are:

The remaining arguments semantic labels and description depend on the value of Option as listed in the following specification tables.

CNCHECK,POST is an action command that solves the initial contact configuration in one substep. The PrepPost (PP) license is incompatable with CNCHECK,POST because it forces a solve operation. After issuing this command, you can postprocess the contact result items as you would for any other converged load step. However, only the contact status, contact penetration or gap, and contact pressure will have meaningful values. Other contact quantities (friction stress, sliding distance, chattering) are available but meaningless.

Initial contact results obtained and listed from CNCHECK,DETAIL, CNCHECK,POST, and the actual solution may not always be consistent with each other. The discrepancy is mainly due to applied boundary conditions and solution options. Contact results from CNCHECK,POST are, in general, closer to what the solution provides than those from CNCHECK,DETAIL.

To inspect the real geometric penetration and gap, specify InterType=1. The program will set KEYOPT(9) = 0 internally during the execution of CNCHECK,POST.

If CNCHECK,POST is issued within the solution processor, the SOLVE command that solves the first load step of your analysis should appear in a different step, as shown in the following example:

/SOLU
CNCHECK,POST
FINISH
. . .

/SOLU
SOLVE
FINISH
. . .

CNCHECK,POST writes initial contact results to a file named Jobname.rcn. The command should be issued before defining analysis type, solution options, and boundary conditions. If the command is issued later, a segmentation violation error may occur. To postprocess the initial contact state, you must read results from the .rnc file using the FILE and SET,FIRST commands in POST1 to properly read the corresponding contact data. Failure to do so may result in improper reading of the results. The following example shows a valid command sequence for plotting the initial contact gap:

/SOLU
CNCHECK,POST                 !write initial contact results to Jobname.rcn
FINISH
/POST1
FILE,Jobname,RCN             !specify the file where results are found 
SET,FIRST                    !read the first data set in Jobname.rcn
PLNSOL,CONT,GAP,0,1
FINISH
. . .

The CNCHECK,RESET command resets all but a few key options and real constants (listed in the following table) associated with the specified contact pairs (RID1, RID2, RINC) to their default values. This option is only valid for pair-based contact definitions.

CNCHECK,ADJUST,,,,0.2,0.01,0.002

CNCHECK,MORPH,,,,0.2,0.01,0.002 ! morph contact pair nodes within the gap
                                ! penetration range of 0.2 to 0.01 and 
                                ! relocate them 0.02 towards the tartget. 

Issue CNCHECK,ADJUST to physically move contact nodes to the target surface. Alternatively, you can issue CNCHECK,MORPH to physically move contact nodes to the target surface and then morph the underlying mesh to improve the mesh quality. See Physically Moving Contact Nodes Toward the Target Surface in the Contact Technology Guide for more information. Similar to the POST option, if CNCHECK,ADJUST or CNCHECK,MORPH is issued within the solution processor, the SOLVE command that solves the first load step of your analysis should appear in a different step:

/SOLU
CNCHECK,ADJUST     ! move contact nodes to the target surface
                   ! or CHCHECK,MORPH to move and then improve mesh quality via morphing
FINISH
. . .

/SOLU
SOLVE
FINISH
. . .

After issuing the CNCHECK,ADJUST or CNCHECK,MORPH command, the initial adjustment is converted to structural displacement values (UX, UY, UZ) and stored in a file named Jobname.rcn. You can use this file to plot or list nodal adjustment vectors or create a contour plot of the adjustment magnitudes via the displacements. When postprocessing the nodal adjustment values, you must explicitly read results from the Jobname.rcn file using the FILE and SET,FIRST commands in POST1 to properly read the corresponding contact data. Otherwise, the results may be read improperly.

CNCH,TADJ,3,,,,,-0.002

Issue the CNCHECK,TADJUST comand to physically move the target body to the contact surface. This command tries to establish initial contact with penetration in a range specified by PMAX and PMIN. Similar to the ADJUST and MORPH options, the initial adjustment is converted to structural displacement values (UX, UY, UZ) and stored in the jobname.rcn file. The CNCHECK,TADJUST command accepts tabular input in the RID1 field.

CHCH,Split        ! default

The SPLIT option is intended for use in a distributed-memory parallel (DMP) run. Use the command CNCHECK,SPLIT to split large contact pairs into smaller sub-pairs so that the smaller contact pairs can be distributed to different cores, thereby improving performance. This functionality is not the same as manually splitting contact pairs during the modeling process. The program splitting logic performs the necessary exchange of data on the boundaries between the split contact pairs to ensure that the results with and without splitting are essentially identical.

CHCH,DMP,,,,,,TRIM,3        ! The program determines the optimal number of contact splits
                            ! and performs trimming using 3 as the global pinball radius.

The DMP option is intended for use in a distributed-memory parallel (DMP) run. Use the CNCHECK,DMP command to split large contact pairs into smaller sub-pairs so that the smaller contact pairs can be distributed to different cores, thereby improving performance. This functionality is not the same as manually splitting contact pairs during the modeling process. The program splitting logic performs the necessary exchange of data on the boundaries between the split contact pairs to ensure that the results with and without splitting are essentially identical. CNCHECK,DMP also performs trimming for bonded and small-sliding contacts and removes inactive pairs from auto-asymmetric contacts before splitting to improve the load balance ratio of DMP runs.

The CNCHECK,MERGE command restores split contact sub-pairs from a previous CNCHECK,SPLIT or CNCHECK,DMP command, enabling postprocessing of a distributed-memory parallel (DMP) solution based on the original pair geometry. It is imperative to exercise caution when a downstream analysis is performed, as the MERGE operation may modify the database.

For more information and examples, see Solving Large Contact Models in a Distributed-Memory Parallel Environment in the Contact Technology Guide.