Failure analysis of polytetrafluoroethylene lined pipe under thermal shock. (February 2023)

• Record Type: Journal Article
• Authors: Gao, Bingjun; Zhang, Aoqing; Lu, Kun; Liu, HongYan
• Is Part Of: International journal of pressure vessels and piping. Volume 201(2023)
• Publication Date: 2023-02
• Subjects: PTFE lined Pipe -- Ratcheting -- Constitutive model -- Ratcheting boundary; Pressure vessels -- Periodicals; Pipe -- Periodicals; Récipients sous pression -- Périodiques; Tuyaux -- Périodiques; Pipe; Pressure vessels; Periodicals; 681.76041
• DOI: 10.1016/j.ijpvp.2022.104871
• Languages: English
• ISSNs: 0308-0161

Abstract

Abstract: In the process of fluid transportation, polytetrafluoroethylene (PTFE) lined pipe is subject to constant thermal stress caused by constant temperature fluid and alternating thermal stress caused by alternate flow of cold and hot fluid, making it susceptible to progressive plastic strain accumulation, namely the ratcheting. In this paper, cold and hot shock tests of PTFE lined pipe at different temperatures were carried out. Ohno-Wang II model was used to predict the ratcheting of PTFE lined pipe under cyclic temperature loading. The simulation result shows that the ratcheting strains occur in the same position as the test result. The equivalent plastic strain control method was used to determine the ratcheting boundary temperature as 145 °C and 90 °C for PTFE lined pipes under cold and hot shock respectively. The ratcheting boundaries of lined pipe with different PTFE lining thickness were given to obtain the influence of lining thickness on ratcheting boundary. Highlights: Thermal shock experiments reveal that significant plastic deformations occur at the flanging of the PTFE lined pipe. Thermal shock cyclic plasticity analysis was analyzed with the Ohno-Wang II kinematic hardening model. Determining the constitutive model parameters by a series of uniaxial tensile and uniaxial ratcheting tests. Thermal shock ratcheting boundary temperature of the PTFE lined pipe was determined.