Creep Analysis in Functionally Graded Rotating Disc Using Tresca Criterion and Comparison with Von-Mises Criterion

A mathematical model is developed to analyse steady state creep stresses and strain rates in a variable thickness rotating FGM disc that yields according to Tresca criterion. The results obtained are compared with those estimated using Von-Mises criterion. The radial stress (except for region towards the outer disc radius) and tangential stress (except for some portion towards the inner and outer disc radii) estimated using Von-Mises yield criterion are observed to be slightly higher than those obtained using Tresca criterion. The Tresca criterion estimates higher values of effective stress throughout as compared to Von-Mises criterion. The strain rates estimated using Tresca criterion, as compared to Von-Mises criterion, are also higher throughout the disc, with the maximum difference noticed at the inner disc radius. Thus, the design of rotating FGM disc, undergoing creep, based on Tresca yield criterion would be much safer as compared to design based on Von-Mises criterion. (C) 2017 Elsevier Ltd. All rights reserved.