{"id":378063,"date":"2024-08-13T06:50:44","date_gmt":"2024-08-13T06:50:44","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/changing-contact-condition-to-displacement-constraints\/"},"modified":"2024-08-14T01:10:39","modified_gmt":"2024-08-14T01:10:39","slug":"changing-contact-condition-to-displacement-constraints","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/changing-contact-condition-to-displacement-constraints\/","title":{"rendered":"Changing Contact Condition to Displacement constraints"},"content":{"rendered":"
Hello, team.<\/div>\n
 <\/div>\n
I am new to Ansys and APDL, so i am sorry if my question is trivial, and thank you in advance.<\/div>\n
 <\/div>\n
I am trying a multi-loadstep mechanical simulation, and I defined a contact condition.<\/div>\n
In the 1st loadstep, I perforemed a simple deformation simulation and it works.<\/div>\n
But the problem is in the 2nd loadstep, where I want the deformed contact to be fixed as it is.<\/div>\n
(And i would like to roll it back to original contact condition in 3rd loadstep, after this problem is solved)<\/div>\n
 <\/div>\n
I tried using “contact step control” so that the contact condition is dead in the 2nd loadstep.<\/div>\n
Meanwhile in the command snippet, I used the command below:<\/div>\n
 <\/div>\n
*GET,nmstp,active,,solu,ncmls<\/div>\n
*IF,nmstp,eq,0,then<\/div>\n
*ELSEIF,nmstp,eq,1,then<\/div>\n
ALLSEL<\/div>\n
DDELE,ALL,ALL<\/div>\n
ALLSEL<\/div>\n
D,moving_parts,UX,%_FIX%,,,,UY,UZ<\/div>\n
D,pdlinnersurf,UX,%_FIX%,,,,UY,UZ<\/div>\n
————————–<\/div>\n
The named selections “moving_parts” and “pdlinnersurf” share the contact areas. (one contains the contact surf and the other contains target surf)<\/div>\n
 <\/div>\n
The solution results in an error, which the msg is:<\/div>\n
 <\/div>\n
 ERROR: Worker process(es) with rank(s) 12, 3, 9 have encountered a FATAL error.<\/div>\n
 The information below was gathered from the file*.out output file(s).<\/div>\n
 Please review the worker process output file(s) listed below for more<\/div>\n
 details on this error.<\/div>\n
 <\/div>\n
 <\/div>\n
 Worker Process Output File .\\file12.out:<\/div>\n
 <\/div>\n
 *** FATAL ***                           CP =    1543.031   TIME= 15:17:22<\/div>\n
 The displacement boundary condition on node 12345 is modified on        <\/div>\n
 multiple domains.         <\/div>\n
———————————-<\/div>\n
 <\/div>\n
When I looked into the nodes, they seem to be in the contact areas.<\/div>\n
So I think the “dead” contact condition somehow still has some constraint in the region, which could not be overriden with displacement constraints.<\/div>\n
I assume that this is because “contact step control” is based on “elements”, rather than “nodes”.<\/div>\n
 <\/div>\n
For more information, step 2 was solved appropriately when solved with a single-core processor. The error occurs when using parallel processing.<\/div>\n
However, with geometry of slightly different parameter, it works.. It drives me crazy and I have no clue.<\/div>\n
 <\/div>\n
 <\/div>\n
I would appreciate any suggestions or clues.<\/div>\n
 <\/div>\n
Thank you,<\/div>\n
Kiyean<\/div>\n

 <\/p>\n","protected":false},"template":"","class_list":["post-378063","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t