Limit analysis of plates-a finite element formulation

A procedure for the computation of the load carrying capacity of perfectly plastic plates in bending is presented. The approach, based on the kinemati c theorem of limit analysis, requires the evaluation of the minimum of a co nvex, but non-smooth, function under linear equality constraints. A systema tic solution procedure is devised, which detects and eliminates the finite elements which are predicted as rigid in the collapse mechanism, thus reduc ing the problem to the search for the minimum of a smooth and essentially u nconstrained function of nodal velocities. Both Kirchhoff and Mindlin plate models are considered. The effectiveness of the approach is illustrated by means of some examples.