BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:Multidimensional coupling in a human knee model
DTSTART:20100211T141500
DTSTAMP:20260507T130809Z
UID:fca231f8f7f79bfdd773445bd608d9b415b7b4359e563f3668337817
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Oliver Sander\nWe present a new way to couple bones modell
 ed as linear elastic three-dimensional objects to ligaments modelled as on
 e-dimensional nonlinear Cosserat rods.  Starting from a full 3d nonlinear 
 elastic formulation we derive suitable coupling conditions for the reduced
  model. These involve the total force and torque transmitted through the i
 nterface as well as its averaged position and an average orientation. The 
 resulting domain decomposition problem is solved using a Dirichlet-Neumann
  algorithm. The configuration space of a special Cosserat rod is the set o
 f all continuous mappings from a given interval to $mathbb{R}3 imes mbox{S
 O}(3)$. We introduce geodesic finite elements as a natural way to discreti
 ze problems in such a nonlinear space. For the minimization of the rod ene
 rgy functional we present an $infty$-norm Riemannian trust-region algorith
 m. In conjunction with a nonsmooth Newton multigrid method as the inner so
 lver this yields an efficient method with provable global convergence.\n\n
 We use this coupling approach to model a human knee joint. The use of rods
  for the ligaments decreases the overall number of degrees of freedom and 
 avoids meshing problems. The additional problem of modelling the contact b
 etween the bones is treated using a mortar element discretization and a no
 nsmooth Newton multigrid method for the solution of the resulting discrete
  system.
LOCATION:MAA112
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR