Appraisal of elastic follow-up for a generic mechanical structure through two simplified methods

Elastic follow-up (EFU) is a complex phenomenon which affects the behaviour of some structural components, especially in high temperature operations. One of the major problems encountered by the designer is the quantitative evaluation of the amount of elastic follow-up that must be taken into account for the structures under examination. In the present paper a review of the guidance furnished by the ASME Code regarding EFU is presented through an application concerning a structural problem in which EFU occurs. This has been carried out with the additional purpose of comparing the percentage EFU obtained by two simplified methods: • —An inelastic simplified method involving relaxation analysis (see Refs 6, 7, 13–16) • —The reduced elastic modulus procedure (see Ref. 13) generally used for EFU problems in piping systems. The results obtained demonstrate a substantial agreement between the two methodologies when applied to a general type structure.