On the shakedown analysis of nozzles using elasto-plastic FEA

The performed shakedown calculations of a dished end with a nozzle in the k nuckle region with varying internal pressure load, and two cylinder-cylinde r intersections with constant moment load and varying internal pressure loa d are example cases for the application of the check against progressive pl astic deformation as stated in the new European UFPV standard, Annex 5.B: " Direct route for design by analysis" (DBA). To calculate the shakedown limi ts, Melan's (lower bound) shakedown theorem is used. In this context, the u sage of the deviatoric maps of stress states to obtain proper self-equilibr ating stress fields is shown. Furthermore, some problems and corresponding possible solutions for performing the shakedown check using a finite elemen t model with shell elements are stated and shown in the examples. (C) 1999 Elsevier Science Ltd. All rights reserved.