Approximations in the reference stress method for creep design

It is shown how a consistent interpretation of the reference stress method in creep design, previously described by the author, can be implemented in practise by way of three simple examples. Reference stresses are extracted for two sets of steady state creep data modelled by Norton, Prandtl, Dorn and Garofalo creep laws. The interpretation of the method employed here is used to show how the effect of material scatter on component prediction can easily be assessed from the results of a uniaxial test alone, The results indicate that a simple approach based on limit behaviour adequately approximations the component behaviour—this has previously only been assumed to be valid for creep laws other than Norton's Law.