[Gmsh] How do I specify a physical group of dimension 1 for the Crack plugin?

Geoff Oxberry goxberry at gmail.com
Tue May 13 19:59:51 CEST 2014


The following .geo file describes what I am trying to do:


/*********************************************************************
 *
 * Minimal crack example
 *
 *********************************************************************/

// Characteristic length made large so the number of elements is small
lc = 1;

// Point: X, Y, Z coordinates, & characteristic length setting elt size
Point(1) = {0, 0, 0, lc} ;
Point(2) = {1, 0, 0, lc} ;
Point(3) = {1, 1, 0, lc} ;
Point(4) = {0, 1, 0, lc} ;

// Lines defined by lists of numbers:
Line(1) = {1, 2} ;
Line(2) = {2, 3} ;
Line(3) = {3, 4} ;
Line(4) = {4, 1} ;
Line(5) = {1, 3} ;

// Line loops to construct surfaces
Line Loop(1) = {1, 2, -5} ;
Line Loop(2) = {5, 3, 4} ;

// Surfaces for meshing
Plane Surface(1) = {1} ;
Plane Surface(2) = {2} ;

Physical Line(105) = {5} ;
Physical Surface(201) = {1} ;
Physical Surface(202) = {2} ;

// Duplicate nodes around Line 5; a mock crack
Plugin(Crack).Dimension = 1 ;
Plugin(Crack).PhysicalGroup = 1 ;
Plugin(Crack).OpenBoundaryPhysicalGroup = 1 ;
Plugin(Crack).Run ;

// End of file

However, when I try to mesh this geometry, I get an error during the
processing:
Physical group 105 (dimension 1) is empty

Geoffs-MacBook-Pro:~ goxberry$ gmsh crack.geo -2
Info    : Running 'gmsh crack.geo -2' [Gmsh 2.8.4, 1 node, max. 1 thread]
Info    : Started on Tue May 13 10:52:25 2014
Info    : Reading 'crack.geo'...
Info    : Running Plugin(Crack)...
Error   : Physical group 105 (dimension 1) is empty
Info    : Done running Plugin(Crack)
Info    : Done reading 'crack.geo'
Info    : Meshing 1D...
Info    : Meshing curve 1 (Line)
Info    : Meshing curve 2 (Line)
Info    : Meshing curve 3 (Line)
Info    : Meshing curve 4 (Line)
Info    : Meshing curve 5 (Line)
Info    : Done meshing 1D (0.000602 s)
Info    : Meshing 2D...
Info    : Meshing surface 1 (Plane, Delaunay)
Info    : Meshing surface 2 (Plane, Delaunay)
Info    : Done meshing 2D (0.000666142 s)
Info    : 5 vertices 14 elements
Info    : Writing 'crack.msh'...
Info    : Done writing 'crack.msh'
Info    : Stopped on Tue May 13 10:52:25 2014

How should I correct my input file so it duplicates the nodes along
Physical Line 105 (equivalently, Line 5)?

Thanks,

Geoff

-- 
Geoffrey Oxberry, Ph.D., E.I.T.
goxberry at gmail.com
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