Application of Elastic-Perfectly Plastic Cyclic Analysis to Assessment of Creep Strain

A cyclic elastic-perfectly plastic analysis method is proposed which provides a conservative estimate to cyclic creep strain accumulation within the ratchet boundary. The method is to check for ratcheting based on an elastic-perfectly material with a temperature-dependent pseudo yield stress defined by temperature, time and stress to give 1% accumulated inelastic strain. It does not require stress classification and is also applicable to a full range of temperature within and below the creep regime. This simplified method could be used as a rapid screening calculation, with full time-dependent creep analysis used if necessary. An ASME Boiler and Pressure Vessel Code, Section III draft Code Case based on this simplified method is introduced.