Primary Creep Design of Thick Tubes

For thick tubes subjected to internal pressure, the estimation of creep-life by the cumulative damage criterion requires knowledge of the time variation of stress and strain at certain critical radii. An approximate method of analysis for primary creep is described which provides the stress and strain data required. The theory is based on a design concept first proposed by Voorhees, et al., and results obtained using the theory with a time-hardening law are presented.