I am writing an application for gear calculations based on getfem and using the "mdbrick_Coulomb_friction" brick. The first results seem encouraging:
http://files.ubuntu-gr.org/forum/logari81/getfem/Screenshot-Kitware%20ParaView%203.4.0_simple_gears2.png but I have difficulties to add augmentation to the Lagrange multipliers for the contact constraints. I 've already read the relevant material from http://math.univ-lyon1.fr/~renard/ --> Publications and http://www.lms.polytechnique.fr/users/khenous/publications.htm but I am not yet in a position to derive the part of the tangent matrix corresponding to the "set_augmented_matrix" method myself. Up to now all my attempts to derive this matrix yield to a zero matrix. I have already studied the contrib/static_friction.cc example but it didn't help me to resolve my question. I would like to ask for some hints or bibliography on the derivation of the tangent matrix of the "mdbrick_Coulomb_friction" brick in the case of augmentation. Please take into account that I haven't studied Mathematics but Mechanical Engineering and most of the books I have read on contact mechanics are from the point of view of an Engineer. Actually I understand more or less the theory presented in e.g. http://math.univ-lyon1.fr/~renard/papers/2007_HR_contact.pdf and http://www.lms.polytechnique.fr/users/khenous/files/coulomb_num.pdf . I also understand the implementation in getfem_Coulomb_friction.h pretty well. What I miss are some steps between the abstract theory and its practical implementation. Additionally I would like to offer my help to expand the contact mechanics infrastructure in getfem. I have already programmed a quite general contact searching algorithm which derives the "BN" and "gap" arrays for the "mdbrick_Coulomb_friction" brick. I could also help with the documentation of the contact brick. Best Regards Kostas _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
