Characterization of GRE Pipes Fatigue Failure Subjected to HTHP Loading Conditions

Author(s):  
Jamil Abdo ◽  
Edris Hassan ◽  
Jan Kwak

Abstract GRE composite pipes are a great substitute for Carbon steel, however, obstacles of introducing GRE composite pipes into oil and gas transmission lines have been primarily related to inadequate testing data to maintain materials’ extended performance and pipes fatigue failure characterization. Customized testing facility has been designed and fabricated to substantiate design of GRE pipes under controlled service conditions. The testing procedure was conducted based on ASTM and ISO Standards. Pipes filled with crude oil were placed in a thermal and pressure enclosure at a temperature of 65°C and an internal pressure of 130 bars for 1000 hours and fatigue failure behavior of the GRE pipes were investigated. Pipes with a surface crack a/t = 0.5 and 0.3 were exposed to alternating internal pressure of 25 cycles/min and a load ratio of R = 0.05. Fatigue tests were performed at two load levels: 50%, and 30% of the pipes strength under static internal pressure. Results show that the GRE pipes burst suddenly without any leakage when the internal pressure was high, however, the pipe exhibit leakage first and then fails when the internal pressure was low. The maximum fatigue life obtain for GRE reference and HTHP specimen pipes in the crack region were 72,237 cycles and 73,107 cycles, respectively, with applied 0.5 static internal pressure (102 MPa) and a/t = 0.3 ratio. The minimum fatigue life obtained in the crack region are 14,105 cycles and 13,627 cycles for GRE reference and HTHP specimen pipes, respectively, with applied 0.5 static internal pressure (170 MPa) for a/t = 0.3 ratio.

Author(s):  
Hojjat Gholami ◽  
Shahram Shahrooi ◽  
Mohammad shishehsaz

Gouge and dent are common mechanical defects in oil and gas pipelines. These defects with plastic strain cause stress concentration in the pipelines. Plastic strain is dependent on initial deformation and spring-back behavior of materials. Therefore, they reduce the fatigue life of pipelines. In this paper, the strain-base fatigue life analysis is investigated in pipelines with smooth dent or combination smooth dent and gouge defects under cyclic internal pressure. For this purpose, elastic-plastic multilinear isotropic hardening finite element simulation was used to investigate the effects of various factors, such as residual stress of dent, amplitude internal pressure, pipe geometry, gouge geometry, and smooth dent geometry on stress concentration factor (SCF). Finally, a new method is proposed for predicting the fatigue life of pipelines with uniform dent and uniform dent and gouge combination defects. The model is presented based on the Smith-Watson-Topper (SWT) criterion. A set of fatigue life test specimens with various pipe materials, size and geometry were prepared and tested. The specimens carried a smooth dent, as well as a combination of smooth dent and gouge defects, results of which were collected to validate those obtained based on the proposed model. The results of the predicted tests using the developed formula showed a good correlation to practical experiments.


Author(s):  
H. Xia ◽  
C. Shi ◽  
J. Wang ◽  
X. Bao ◽  
H. Li ◽  
...  

Abstract Thermoplastic composite pipes (TCPs) are increasingly used to transport hydrocarbons and water in the oil and gas industry due to their superior properties including corrosion resistance, thermal insulation, light weight, etc. The cross-section of TCPs generally consists of three layers: inner liner, composite laminate, and outer jacket. Three layers are bonded together and form a solid-wall construction. Inner liner and outer jacket made of thermoplastic polymer provide protective barriers for the laminate to against the inner fluid and outer environment. The laminate is constructed by an even number of helically wounded continuous fiber reinforced thermoplastic composite tapes. In this study, mechanical behaviors of a TCP under an internal pressure were investigated by using analytical and finite element analysis (FEA) methods. The analytical method which is based on the three-dimensional (3D) anisotropy elastic theory can take account of non-uniformly distributed stress and strain through the thickness of the pipe wall. FEA models were setup by using the software ABAQUS to predict the stress distribution of the pipe. 3D Tsai-Wu failure criterion was used to predict the maximum internal pressure of the pipe. Effects of some critical parameters, such as the winding angle of composite tapes and the number of reinforced plies, on the internal pressure capacity of TCPs were studied. Results obtained from the analytical and FEA methods were fairly agreed with each other, which showed that with the increasing of the number of reinforced plies the internal pressure capacity of a TCP gradually increases and approaches to an extreme value. In addition, the optimal winding angle which results the maximum internal pressure is not a constant value, instead, it varies with the increasing thickness of the laminate layer. This study provides useful tools and guidance for the design and analysis of TCPs, and is currently under validation through experiments.


2019 ◽  
Vol 300 ◽  
pp. 09003
Author(s):  
Benaïssa Malek ◽  
Catherine Mabru ◽  
Michel Chaussumier

The purpose of the present research project is to study multiaxial fatigue behavior of 2618 alloy. The influence of mean stress on the fatigue behavior under tension and torsion is particularly investigated. Fatigue tests under combined tensile-torsion, in or out of phase, as well as combined tensile-torsion-internal pressure tests have also been conducted. Multiaxial fatigue results are analyzed according to Fatemi-Socie criterion to predict the fatigue life.


2009 ◽  
Vol 30 (10) ◽  
pp. 4293-4298 ◽  
Author(s):  
Lokman Gemi ◽  
Necmettin Tarakçioğlu ◽  
Ahmet Akdemir ◽  
Ömer Sinan Şahin

2011 ◽  
Vol 46 (9) ◽  
pp. 1041-1050 ◽  
Author(s):  
A Samanci ◽  
N Tarakçioğlu ◽  
A Akdemir

In this study, the fatigue behavior of (±45°)3 filament-wound composite pipes with a surface crack under alternating internal pressure was investigated. Glass-reinforced plastic (GRP) pipes were made of E-glass/epoxy and tested in the open-ended condition. The pipes had a surface crack with a notch–aspect ratio of a/c = 0.2 and notch-to-thickness ratios of a/t = 0.25, 0.38, or 0.50 in the axial direction. Tests were carried out in accordance with ASTM D2992. This standard offers 25 cycles/min and a load ratio of R = 0.05. Tests were performed at three different load levels: 50%, 40%, and 30% of ultimate hoop stress. Whitening, leakage, and final failure of GRP pipes were observed, and fatigue test results were presented by means of S–N curves.


2020 ◽  
Vol 14 (3) ◽  
pp. 7170-7180
Author(s):  
S. Mazlan ◽  
N. Yidris ◽  
R. Zahari ◽  
E. Gires ◽  
D.L.A. Majid ◽  
...  

The change in material properties at low temperature has always been one of the concerned design factors in aircraft industries. The wings and fuselage are repeatedly exposed to sub zero temperature during cruising at high altitude. In this study, fatigue tests were conducted on standard flat specimens of aluminum 2024-T3 at room temperature and at -30 °C. The monotonic and cyclic loading tests were conducted using MTS 810 servo hydraulic machine equipped with a cooling chamber. The monotonic tests were conducted at a crosshead speed rate of 1 mm/min and the cyclic tests at a frequency of 10 Hz with a load ratio of 0.1. The experimental data obtained, such as the yield strength, ultimate strength and S-N curve were used as the input parameters in ANSYS Workbench 16.1. This close agreement demonstrates that the isotropic model in ANSYS workbench is essential in predicting fatigue life. The increase in stress parameter causes fatigue life to decrease. Besides, the decrease in temperature causes the total fatigue life to increase.


Author(s):  
Guoqiang Li ◽  
Su-Seng Pang ◽  
Randy J. Jones ◽  
Jack E. Helms ◽  
Eyassu Woldesenbet

Abstract Deepwater activities are the future of the Offshore Oil and Gas Industry. Huge reserves have been located in the Gulf of Mexico as well as off the Coast of West Africa and Brazil. The development of floating production platforms and vessels offers challenges to the facilities engineer who must consider new materials to meet stringent topsides weight limitations. A critical technology for facilities piping in offshore platforms is joining technique. This paper discusses the development of a hybrid joining approach by using heat-activated coupling and adhesive bonding. The technique procedure is presented via specimen fabrication. A total of eleven coupled specimens are prepared and evaluated using standardized internal pressure tests. The feasibility of this new joining technique in offshore piping is discussed based on the internal pressure test results.


Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1825 ◽  
Author(s):  
Fulin Liu ◽  
Hong Zhang ◽  
Hanqing Liu ◽  
Yao Chen ◽  
Khan Muhammad Kashif ◽  
...  

The electron beam welding process is widely used in the connection among titanium alloy material parts of aero-engines. Its mechanical properties need to meet the requirements of long life and high reliability. In this paper, the static strength and the fatigue failure behavior of the electron beam weldments of TC17 titanium alloy were investigated experimentally under low amplitude high frequency (20 kHz), and the mechanical response and failure mechanism under different external loading conditions were analyzed. In summary, the samples were found to have anisotropic microstructure. The tensile strength of the PWHT of TC17 EBW joint was ~4.5% lower than that of the base metal. Meanwhile, compared with the base metal, the fatigue strength was reduced by 45.5% at 109 cycles of fatigue life. The fracture analysis showed that the fatigue failure of the welded joint of TC17 alloy was caused by the welded pores and the fatigue cracks initiated from the welded pores. A fine granular area (FGA) was observed around the crack initiation region. The existence of pores caused the stress intensity factor of the fine granular area (KFGA) to be inversely proportional to the fatigue life. The KFGA calculation formula was modified and the fatigue crack propagation threshold of the welded joint of TC17 alloy was calculated (3.62 MPa·m1/2). Moreover, the influences of the effective size and the relative depth of the pores on the very long fatigue life of the electron beam welded joint of TC17 titanium alloy were discussed.


Author(s):  
Muhammad A. Wahab ◽  
Prashanth Ramachandran ◽  
Su-Seng Pang ◽  
Randy A. Jones

This paper discusses an experimental and numerical study to investigate the failure behavior of non-conventional cross-sectioned fiber reinforced composite pipes filled with glass beads subjected to internal pressure and bending loads. An adaptive filament winder for non-conventional pipes was exclusively designed to fabricate the samples used in the experiments. Experiments were conducted on triangular and rectangular cross-sectioned samples as per ASTM standards to find the internal burst pressure, bending strength, and failure modes of the pipes. Numerical analysis for the pipe loading process has been developed based on the finite element method for a linear orthotropic problem for composite pipes. The finite element software ANSYS was used to build the model and predict the stresses imposed on the pipes. The relationships between the applied internal pressure and peak hoop stress, bending load, and bending strength with reference to the fillet radius were determined; and generally a good correlation was found between the experimental and numerical results.


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