1 Topic by jagh (edited by jagh 2009-11-12 10:08:30)

  • jagh
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  • Registered: 2009-11-11
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Topic: error message concerning contact

I'm learning to use ATENA 3D and I would like to make a numerical simulation where an headed anchor is intalled in a concrete block and is pull-out of this concrete block. In this model I need to define contact between the anchor and the concrete block. I was looking in the ATENA's manual and I use the 3D interface law. ATENA Automatically identifies the contact surfaces and I define this law for the contact.

When I launch the simulation I'm getting a message in the run module which is the following:

Invalid master-slave pair/group BC, master(s) 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1027 1028 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1034 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1033 , at least one dof of slave: 10658 could not be constrained,  specified in support id: 2, load case id 738197513, name: Contact:: VOLUME 402653186 SURFACE 603979812 to VOLUME 402653185 SURFACE 603979789; BC ignored.

I'm not understanding why there is a problem with master-slave pair. Initially, the definition of the master was done automatically by ATENA and after I defined, but the message still appeares. Could anyone help me and explain what may be wrong?
Thank you.

José

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  • dpryl
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Re: error message concerning contact

This warning usually occurs for Degrees of Freedom (DoFs) of nodes on a contact, that are already fixed, e.g., supported, on an edge where 2 contacts meet, etc. A very similar warning occurs when no master node can be found for a slave. Then, you many need to prescribe (or switch) which surface should be master and which slave - we recommend to set the surface with larger elements as master (automatically, the larger surface is set as master).

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