COMSOL Multiphysics™

elpric
Purpose
elpric
Define variables which evaluate principal values and vector components.
Syntax
Description
el.elem = 'elpric'
el.g{ig} = geomnum
el.basename = bname
el.postname = pname
el.sdim{idim} = dimname
el.geomdim{ig}{edim}.ind{eldomgrp} = domainlist
el.geomdim{ig}{edim}.tensor{eldomgrp} = matexpr
The elpric element evaluates eigenvalues and eigenvectors of a 3-by-3 real
symmetric matrix. The tensor field always has six components specifying the upper
triangle of the source matrix as a cell array of expressions in column order. The
basename field is compulsory and specifies a single name from which all output
variable names are derived. The output variables are defined wherever the tensor
field is non-empty.
Eigenvalue variable names are created by appending numbers 1 to 3 to bname and,
if postname is present, append '_pname'. Eigenvector component names are then
created by inserting the space variable names given in sdim directly after the
component number. Eigenvalues are sorted in decreasing order.
Cautionary
Examples
No Jacobian contribution is calculated even if the tensor expressions contain
dependent variables. The reason is the condition that the eigenvalues are sorted,
which makes the eigenvector components discontinuous functions of the input
matrix components.
Define postprocessing variables for principal strains and directions, given strain
components [ex,ey,ez,exy,exz,eyz].
el.elem = 'elpric';
el.g = {'1'};
el.basename = 'e';
el.sdim = {'x','y','z'};
gd.ind = {{'1'}};
gd.tensor = {{'ex','exy','ey','exz','eyz','ez'}};
el.geomdim{1} = {{},{},{},gd};
fem.elem = [fem.elem {el}];
See Also
elempty, elinv
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