The Development of High Temperature Design Methods Based on Reference Stresses and Bounding Theorems

The paper summarizes some recent developments in the analysis of structures by use of bounding theorems and reference stress techniques. In many instances these techniques may be used by design engineers in simplifying the analysis of structures operating in the creep range. This is particularly true of components operating below a modified shakedown limit as the design methods need be no more complex than those currently used below the creep range. Above the modified shakedown limit bounding theorems may be used to determine deformations but require a cyclic elastic-plastic solution as a minimum requirement. The bounds however do allow a simplified treatment of the creep deformation to be made.