On Wednesday 17 October 2007 10:10, you wrote: > Hello, > > I have a question about the boundary conditions. > I am using your test demo nonlinear_elastostatic.cc . Let's suppose > I neither consider the gravitation forces nor the torsion, but > I just prescribe some extension (ie. I displace the top face of the bar > using the Dirichlet boundary conditions). > What I want is to compute the deformation of the bar (that is OK) > but moreover, I want to calculate the force vector which is acting > in the top face which is displaced. I use the AUGMENTED_CONSTRAINTS > for the Dirichlet condition and so > for each prescribed displacement in the nodes of the top face I get > a coefficient in the solution vector. How can I use them in GetFem > to compute the overall force vector (f_x, f_y, f_z)? > > I tried simpler version of the deformation -- I just prescribed the > displacement one node of the mesh (in x,y,z). Then (using again the > AUGMENTED_CONSTRAINTS) I got three numbers in the tail of the solution > vector and I considered them being the forces f_x, f_y and f_z acting in > that displaced point of the mesh. Is this correct? >
Yes, the component of the multiplier corresponding to a certain node represents a so called "equivalent force" at this node. If you need the force density, you have to use the shape functions of the multiplier fem used. Yves. -- Yves Renard ([EMAIL PROTECTED]) tel : (33) 04.72.43.87.08 Pole de Mathematiques, fax : (33) 04.72.43.85.29 Institut Camille Jordan - CNRS UMR 5208 INSA de Lyon, Universite de Lyon 20, rue Albert Einstein 69621 Villeurbanne Cedex, FRANCE http://math.univ-lyon1.fr/~renard --------- _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
