NUMERICAL SHAKEDOWN ANALYSIS OF AXISYMMETRICAL SANDWICH SHELLS - AN UPPER BOUND FORMULATION

Shakedown analysis of axisymmetric elastic-perfectly plastic sandwich shells is performed here using a new upper bound formulation based on a special form of Koiter's theorem concerning piecewise linearized yield surfaces. Starting from finite element techniques and the Tresca sandwich yield condition, shakedown analysis is reduced to a linear programming problem which is solved by a powerful simplex algorithm. Numerical results are given for a number of examples and a comparison is made with a previously computed lower bound formulation.