COMSOL Multiphysics™

elcontact
Purpose
elcontact
Define contact map operators.
Syntax
el.elem = 'elcontact'
el.g{ig} = geomnum
el.opname{iop} = opname
el.gapname{iop} = gapname
el.contname{iop} = contname
el.conttol{iop} = 'auto' | abstol
el.visname{iop} = visname
el.method = 'direct' | 'ball'
el.checkdist = chkdist
el.srcframe{iop} = frame
el.srcn{iop}{idim} = srcnx_i
el.dstx{iop}{idim} = dstx_i
el.dstn{iop}{idim} = dstnx_i
el.geomdim{ig}{edim}.ind{eldomgrp} = domainlist
el.geomdim{ig}{edim}.src{iop} = eldomgrplist
Description
The elcontact element defines contact map operators and related gap distance,
contact flag and visibility flag variables.When evaluated, a contact map operator
searches for the closest source (or master) point found following a ray in the dstn
direction from the point given by the dstx expressions evaluated at the destination
(or slave) point.
For each operator name, a set of master domains is specified by listing one or more
domain group indices in the corresponding el.geomdim{ig}{edim}.src{iop}
field. Normal direction expressions for the master domains are specified in the
el.srcn{iop}{idim} fields. Coordinate expressions for the master are obtained
indirectly from the frame specified in the el.srcframe{iop} field.
The map operator allows evaluation of any expression at a corresponding master
point, while the gap distance variable evaluates to the distance between master and
slave point. The contact flag variable evaluates to a nonzero value if the master point
is well-defined and the gap distance less than the conttol treshold value. The
visibility flag variable is nonzero if a corresponding master point was found for the
slave point where the flag is evaluated.
There are two slightly different methods available to search for master points. The
'direct' method is a clean and stable direct search algorithm while the 'ball'
method is faster by only treating master elements inside a given ball radius
accurately. This ball radius can be set using the checkdist field, and should
normally be larger than any mesh element taking part in the search.
55