ON EXTREMUM-PRINCIPLES AND ALGORITHMS FOR SHAKEDOWN ANALYSIS

Extremum principles for structures under variable loads are considered . Classical shakedown theory is compared with the exclusive prevention of incremental collapse and also with a safety analysis for alternati ng plasticity. A general kinematical minimum principle for incremental collapse is derived from the generalization to non-polyhedral load do mains of a criterion due to J. Konig. A mixed principle for incrementa l collapse, and also a static principle, are proposed here. A numerica l procedure for the computation of the safety factor against increment al collapse is developed on the basis of these theoretical results.