Optimal Design of Structures Under Creep Conditions

Abstract

Optimal design of structures, or rather just of simple structural elements working under creep conditions, belongs to the most recent branches of structural optimization: it was initiated by four papers published in the years 1967–8 (Reytman, Prager, Nemirovsky, Zyczkowski). The most important differences with respect to elastic or plastic design are as follows: factor of time appearing in the constraints, a great variety of constitutive equations of creep or viscoplasticity, of creep rupture hypotheses, creep buckling theories, various definitions of creep stiffness etc. Moreover, the constraints related to stress relaxation are quite new. So, it is almost impossible to establish a sufficiently general theory and various types of problems must be treated separately by appropriate methods.