Dear Stephan, The easiest way to do this now (but for that you have to download the svn version of Getfem) is to use the generic interpolation (see http://download.gna.org/getfem/html/homepage/userdoc/interMM.html#interpolation-based-on-the-high-level-generic-assembly-langage and http://download.gna.org/getfem/html/homepage/userdoc/gasm_high.html#ud-gasm-high).
For instance the interpolation of the whole stress ca be done with the string "lambda*Trace(Grad_u)*Id(meshdim) + mu*(Grad_u + Grad_u')" if u is the variable representing the displacement and lambda, mu the Lamé coefficients. So you can use the function getfem::ga_interpolation_Lagrange_fem(md, "your expression to be interpolated", mf, result, rg=mesh_region::all_convexes()); to perform the interpolation (mf should be a Lagrange fem). If rg is a boundary region, you can use the keyword "Normal" to refer to the unit outward normal to the boundary. The Von Mises stress can be obtained with the string "sqrt(3/2)*Norm(Deviator(lambda*Trace(Grad_u)*Id(meshdim) + mu*(Grad_u + Grad_u')))". Yves. ----- Original Message ----- From: "Stephan Gekle" <[email protected]> To: [email protected] Sent: Monday, April 28, 2014 5:53:16 PM Subject: [Getfem-users] Stress tensor / normal stress on surface Dear all, I am using the 'isotropic linearized elasticity brick'. Is there an easy way to obtain the local stress tensor sigma throughout the material? And similarly the tangential / normal stress on the surface? Or is it necessary to compute that manually using the derivatives of the displacements... if so, has anybody a piece of code at hand to do this? Thanks a lot for any help, Stephan _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
