Eun-Yup Lee/Young-Shin Lee/Qui-Ming Yang/Jae-Hoon Kim/Ki-Up Cha/Suk-Kyun Hong
The Journal of Mechanical Science and Technology, vol. 23, no. 12, pp.3153-3160, 2009

Abstract : The autofrettage process enhances the carrying capacity and fatigue lifetime of pressure vessels by increasing their residual stress. A compound cylinder was introduced in order to increase residual stress. An autofrettaged compound cylinder can resist a higher pressure than a single cylinder having the same dimension. This residual stress can be measured through experimental or calculation processes. In this study, residual stress analysis of an autofrettaged compound cylinder was conducted. The elastic-perfectly plastic and strain hardening models were investigated. The residual stress distribution of the autofrettaged compound cylinder with shrink fit tolerance was predicted. Shrink fit is a very efficient way to extend compressive residual stress. The compressive residual stress of the strain-hardening model is smaller than that of the elastic-perfectly plastic model because of the Bauschinger effect. The compressive residual stress of the strain hardening model decreased by up to 80% overstrain level.

Keyword : Autofrettage process; Compound cylinder; Elastic-perfectly plastic model; Strain hardening model