Original paper(Vol.46 No.4 pp.354)
Estimating method for creep property of GFRP laminated pipe
Iwamoto Masaharu; Kurashiki Ken; Araki Shigetoshi; Ohkubo Shin
Abstract:The purpose of the present work is to estimate the behavior of creep deformation of GFRP pipe under an internal hydraulic pressure where the both ends are free. The GFRP pipe is developed for renewal of an overage drain pipe or gas pipe. It is mainly made up of two layers where the glass fiber mat is used in the inside layer for corrosion resistance and the woven roving cloth is as the outside layer for pressure resistance.
Before the internal hydraulic pressure creep test, the tensile creep tests are carried out with the dumbbell type specimen which is cut from the uncured laminated pipe and then is cured. The creep constitutive equation is obtained using the tensile creep data of short-term tests, by taking account of stress, temperature and tensile angle to reinforced glass fiber. Based on this creep constitutive equation, long-term creep behavior can be predicted. A reasonable comparison between the prediction and the tensile experiment is observed at time up to 106 second. The internal hydraulic pressure creep test on the pipe verified the creep constitutive equation.
Key Words:tensile creep, internal pressure creep, creep constitutive equation, FRP pipe, Poisson's ratio