I really am not understanding how to record the eigen values or eigen vectors when using a quad element (or any continuum element).
Can you supply me with instructions?
eigen values and eigen vectors
Moderators: silvia, selimgunay, Moderators
the eigenvectors are recorded using nodal recorders (one eigenvector per recorder) .. the eigenvalues cannot be obtained using a recorder; instead you use plain tcl to o/p them once you have obtained them (the eigen command returns them in a string):
set outfile [open eigenvalues.txt w]
set eigenvalues [eigen 4]
puts $outfile $eigenvalues
close $outfile
recorder Node -file eigenvectors1.out -node 2 3 -dof 1 2 3 "eigen 1"
recorder Node -file eigenvectors2.out -node 2 3 -dof 1 2 3 "eigen 2"
recorder Node -file eigenvectors3.out -node 2 3 -dof 1 2 3 "eigen 3"
...
analyze 1; // you need at least 1 analyze to get them! to be recorded
if still confused, have a look at this script i have posted:
http://opensees.berkeley.edu/community/ ... .php?t=426
set outfile [open eigenvalues.txt w]
set eigenvalues [eigen 4]
puts $outfile $eigenvalues
close $outfile
recorder Node -file eigenvectors1.out -node 2 3 -dof 1 2 3 "eigen 1"
recorder Node -file eigenvectors2.out -node 2 3 -dof 1 2 3 "eigen 2"
recorder Node -file eigenvectors3.out -node 2 3 -dof 1 2 3 "eigen 3"
...
analyze 1; // you need at least 1 analyze to get them! to be recorded
if still confused, have a look at this script i have posted:
http://opensees.berkeley.edu/community/ ... .php?t=426