Life Prediction of the Tapered Pipe With High Temperature and High Pressure by Finite Element Methods

2007 ◽  
Author(s):  
Juntao Bao ◽  
Jianming Gong ◽  
Shantung Tu ◽  
Yuesheng Li ◽  
Yanfei Qiu
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
High Temperature ◽  
Internal Pressure ◽  
Creep Damage ◽  
Piping System ◽  
Bending Moments ◽  
Finite Element Program ◽  
Element Program ◽  
Main Steam

Tapered pipe used in the main steam pipelines, which operated at high temperature and high pressure, including concentric tapered pipe and eccentric tapered pipe, they are sources of weakness in the piping system serviced in the power stations and the chemical plants, and creep is the significant reason that caused their failure. Creep damage analyses are carried out for these two kinds of tapered pipes by introducing user subroutine based on the modified Karchanov-Rabotnov constitutive equations into finite element program ABAQUS, then the effects of bending moments and internal pressure to the serviced life of the components are investigated by comparing four group of calculated results under different loads, the results indicated that eccentric tapered pipe is more inclinable to broken than concentric tapered pipe under the same conditions, so it is not recommended to use the eccentric tapered pipe in the piping system. The bending moments will accelerate the components’ failure, so it is necessary to take some advantages to reduce the bending moments near the tapered pipe, on the other hand, the life of the tapered pipe will decrease quickly with the internal pressure increasing, so the control of the operated pressure is important to ensure the serviced life of the pipelines.

On-Line Health Monitoring Research on T-Joint of Main Steam Piping

2013 ◽  
Vol 330 ◽  
pp. 549-552 ◽  
Author(s):  
J.H. Jia ◽  
H.C. Zhang ◽  
X.Y. Hu ◽  
L.P. Cai ◽  
S.T. Tu
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Residual Life ◽  
Thermal Power ◽  
Creep Damage ◽  
Piping System ◽  
Main Challenge ◽  
On Line ◽  
Main Steam ◽  
Creep Monitoring

The main challenge of long-time creep monitoring on site is a reliable sensor. In this paper, a sensing device is developed specifically for high temperature creep monitoring. And it is applied to on-line monitor the strain of material on T-joint of main steam piping. Its reliability is verified theoretically using the finite element method and experimentally by high temperature on site test. The creep damage of the T joint is evaluated basing on the creep rate sensed by the sensing device. And the residual life is predicted for the piping system using the Monkman-Grant equation. This system is useful for safety assessment procedures in thermal power plant, nuclear power plant and petrochemical industries.

Stress Distribution in the Region Around Two Normally Intersecting Pipes due to In-Plane Bending Moments Using Finite Element Method

1997 ◽  
Author(s):  
Darmawan Harsokoesoemo ◽  
Gatot Santoso
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Bending Moments ◽  
Finite Element Program ◽  
Data Presentation ◽  
Calculated Stress ◽  
Intersecting Pipes ◽  
Element Program ◽  
Plane Bending

Numerically calculated stress in the region of two normally intersecting pipes due to in-plane bending moments using finite element program MECHANICA are presented in this paper. The computer results were processed and then presented in stress versus location (along several lines) diagrams. Other investigators’ results for similar problem are not easy to obtain due to differences in the problem, in modelling, in finite element program used and in methods of data presentation. Lock et al (1985) and Moffat et al (1984) works were the closest for comparison purposes.

Influence of Internal Inward Pressure on Stability of Open-Top Aboveground Steel Tanks Subjected to Wind Loading

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Yen-Chen Chiang ◽  
Sukru Guzey
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Wind Loading ◽  
Finite Element Program ◽  
Element Program ◽  
Steel Tanks ◽  
Post Buckling ◽  
Design Documents ◽  
Wind Profiles ◽  
Mesh Convergence

The results of wind tunnel tests indicate that there is an internal inward pressure induced by wind excitation when open-top tanks are examined, but not when close-top tanks are examined. This internal pressure is considered in many design documents outside of the U.S., however, ASCE-7 and API 650 do not explicitly address this factor. This study examined the effect of this internal pressure by conducting finite element analyses. Open-top tanks with height to diameter ratios of 0.11, 0.2, 0.5, 1.0, 2.0, and 4.0 were modeled using a finite element program. A linear bifurcation analysis and a post-buckling analysis were then conducted to verify the tank's stability when subjected to wind loading in accordance with the wind profiles specified in the selected design documents. To ensure the quality of the analyses, a study on mesh convergence and the load increment of Riks analysis was conducted. It was determined that the presence of the additional internal pressure term has a drastic impact on the buckling capacity of all the tanks examined. As a consequence, it can be concluded that the additional internal pressure generated by the wind on an open-top tank should not be neglected.

Failure Investigation of a Low Chrome Long-Seam Weld in a High-Temperature Refinery Piping System

1995 ◽  
Vol 117 (3) ◽  
pp. 227-237 ◽  
Author(s):  
G. M. Buchheim ◽  
D. A. Osage ◽  
R. G. Brown ◽  
J. D. Dobis
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Stress Analysis ◽  
Hoop Stress ◽  
Weld Seam ◽  
Creep Damage ◽  
Piping System ◽  
Testing Program ◽  
Metallurgical Investigation ◽  
Fabrication Tolerances

The results of an investigation of a long-seam welded low chrome pipe that failed in a high-temperature refinery piping system are presented in this paper. Based upon the results of a metallurgical investigation, which included a creep testing program and a detailed finite element stress analysis, the cause of the failure has been attributed to creep damage at the weld seam. The metallurgical investigation and creep testing program indicated that the 1-1/4 Cr-1/2 Mo pipe material was normalized and exhibited greater than average creep strength and creep ductility. The results of a piping stress analysis indicated that all pressure, weight, and thermal stresses were in compliance with the ASME B31.3 Piping Code (ASME, 1993a). Nonetheless, the pipe failed after only 100,000 h at a nominal hoop stress of 6 ksi (41.4 MPa) with an operating temperature range of 970°F (521°C) to 1000°F (538°C). Results from subsequent detailed finite element stress analyses of the failed pipe indicated that very high localized bending stresses were present in the pipe due to peaking at the long-seam weld. These stresses partially relax by creep, but after 100,000 h they were still approximately 38 percent higher than the nominal hoop stress. The creep strains resulting from stress relaxation and those associated with the long-term value of the sustained stresses cause severe creep damage at the weld seam. As a result of this damage, cracks initiated at the inside of the pipe and primarily grew through the HAZ/fusion line until an 18-in. through-wall crack developed. The pipe was produced to ASTM A691, Grade 1-1/4 Cr, Class 41 (ASTM, 1989), and the peaked geometry was found to satisfy the fabrication tolerances of this standard. The need for the development of an acceptable tolerance for peaking in addition to the outside diameter and out-of-roundness fabrication tolerances currently included in this standard is highlighted for long-seam welded pipe that is to operate in the creep range.

Ultrasonic Sensor for High Temperature Gas Filled Vessels

2006 ◽  
Author(s):  
J. S. Sandman ◽  
B. R. Tittmann
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Target Location ◽  
Ultrasonic Transducer ◽  
Piezoelectric Element ◽  
Ambient Air ◽  
High Energy ◽  
Finite Element Program ◽  
Housing Design ◽  
Element Program

The focus of this paper is an Ultrasonic Position Indication System (UPIS) that is capable of determining one-dimensional target location in a high temperature steel-container with gaseous medium. The combination of the very high acoustical impedance of steel (45.4MRayl) and the very low impedance of air (0.0004MRayl) causes extremely high-energy losses upon transmission. In addition to the energy loss, propagation through a steel plate produces many internal reflections in the plate. The strategy of this investigation was to develop a self-contained ultrasonic transducer that is capable of replacing a small portion of a high temperature-pressure boundary. In building such a transducer, sufficient acoustic matching layers for the steel-gas interface, a mechanically and acoustically competent housing, a sufficient piezoelectric element, and backing materials are all developed and tested. The results include a successful housing design, high-temperature acoustic matching layers, and subsequent successful waveforms. Target location through 9.6” (24.5cm) of ambient air was successful, with a steel pressure boundary 0.4566” (1.1598cm) thick, and using one matching layer. In addition to the experimental results, this investigation includes numerical simulations. Sample waveforms were predicted one-dimensionally with the Mason model using MatLab, and two-dimensionally with a Coupled Acoustic Piezoelectric Finite Element Method (CAPA) program. The Mason model program predicts waveform changes as the wave travels through various interfaces. CAPA is a finite element program that predicts waveforms based on the equations for ultrasonic wave propagation.

Coupled Analysis of SCR and Flowline Under High Pressure and High Temperature

2014 ◽  
Author(s):  
C. H. Luk ◽  
Xinhai Qi ◽  
Jianxia Zhong
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Thermal Stresses ◽  
Dynamic Responses ◽  
Coupled Analysis ◽  
Finite Element Program ◽  
Steel Catenary Riser ◽  
Element Program ◽  
Lateral Displacements ◽  
Vessel Motion

This paper presents a coupled design analysis for a Pipe-in-Pipe (PIP) Steel Catenary Riser (SCR) and Flowline (FL) system in 5000ft of water under high pressure and high temperature (HP/HT) conditions in the Gulf of Mexico (GOM). The finite element program ABAQUS is used to model the inner and outer pipes of the PIP system, the centralizer, the SCR hangoff, the flowline lateral and end supports, and pipe-soil interactions on the seabed. Thermal stresses and stress ranges caused by repeated temperature transients, axial and lateral displacements of SCR and flowline, as well as by the dynamic responses of the coupled riser and flowline system, are presented. Comparisons are also made with results by ABAQUS models with beam and pipe elements, and results obtained by coupled and de-coupled analysis. The sample vessel motion was obtained for an example Spar platform in GOM.

Experimental measurement and finite element analysis of the deformation of a high-pressure sluice gate

2000 ◽  
Vol 27 (4) ◽  
pp. 655-670
Author(s):  
Chuen-Shii Chou ◽  
Shou-Chih Lou
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Water Pressure ◽  
Sluice Gate ◽  
Water Release ◽  
Element Analysis ◽  
Finite Element Program ◽  
Safety Monitoring System ◽  
Element Program ◽  
Water Height

The deformation of a high-pressure sluice gate under an orthogonal water pressure load of 0.539 MPa (i.e., 55 m water height), acting upon the upstream side of a gate leaf, was studied numerically and experimentally. The sluice gate was installed at the end of a water-release tunnel in the Nan-Hwa Reservoir, Nan-Hwa, Taiwan, R.O.C. The numerical results obtained using the ANSYS 5.5.2 finite element program agreed reasonably well with the experimental data. The deformation of this high-pressure sluice gate under water pressure loads of 0.736 MPa (i.e., 75 m water height) and 0.931 MPa (i.e., 95 m water height) was predicted by ANSYS 5.5.2. The research reported here may provide a method for establishing a safety monitoring system for any high-pressure gate and provide engineers with useful information to evaluate the possibility of increasing the capacity of an existing reservoir.Key words: sluice gate leaf, finite element method (FEM), strain gauge, water pressure.

Assessment of Fracture Integrity for Trawl Impact of the Ormen Lange SFD Pipelines

2009 ◽  
Author(s):  
Erlend Olso̸ ◽  
Ba˚rd Nyhus ◽  
Erling O̸stby ◽  
Morten Hval ◽  
Hans Olav Knagenhjelm
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Structural Integrity ◽  
Element Model ◽  
Gas Field ◽  
Finite Element Program ◽  
Field Development ◽  
Integrity Assessment ◽  
Element Program ◽  
Pipeline Design

Ormen Lange Southern Field Development (SFD) is part of the phase 2 development of the Ormen Lange gas field located about 120 km offshore the coast of Norway. The SFD includes an 8 slot template, two 16 inch infield flowlines, one 6 5/8 inch MEG line and one umbilical located at about 850 m water depth. Although there are presently no fishing activities at the development area, the pipeline design has included a design case with evaluation of the structural integrity and potential for failure caused by future interaction with fishing gear such as trawl impact/pull-over and hooking. In contrast to the MEG line and the umbilical, which will be trenched and buried along the whole pipeline route, the 16 inch production flowlines will be left exposed on the seabed and may therefore be subjected to interference with trawl equipment in the future. It was therefore decided that pipeline engineering shall document that impact from trawl equipment during operation will not cause detrimental damage to the exposed flowlines, resulting in leakage of hydrocarbons to the environment and/or high cost of repair. In the event of impact from trawl equipment, it is likely that the pipe will be operating and thus be in a state of internal overpressure. Recent research has shown that the effect of internal pressure can be detrimental to the fracture response of pipelines with circumferential flaws subjected to bending or tensile loading. Today’s analytical equations that are the basis for most engineering critical assessments (ECA) are not capable of accounting for the effect of internal pressure when elastic-plastic fracture mechanics is considered. LINKpipe, which is a special purpose finite element program for assessing the fracture integrity of pipelines, is capable of accounting for the effect of internal pressure and was therefore chosen for the fracture integrity assessment. The flowline was analyzed for a range of defect sizes and material stress-strain behaviors. The finite element model was subjected to bending while under internal pressure, and both surface breaking defects and embedded defects have been assessed to ensure that the Ormen Lange SFD flowlines are capable of withstanding impact from trawl equipment during operation. The analyses were used to determine safe operational windows regarding acceptable defect sizes for both surface breaking and embedded defects for the parameters analyzed.

scholarly journals MULTI-OBJECTIVE OPTIMIZATION OF GRILLAGES APPLYING THE GENETIC ALGORITHM / DAUGIAKRITERIS SIJYNŲ OPTIMIZAVIMAS GENETINIAIS ALGORITMAIS

2012 ◽  
Vol 3 (6) ◽  
pp. 47-52
Author(s):  
Darius Mačiūnas ◽  
Rimantas Belevičius ◽  
Juozas Kaunas
Keyword(s):  
Finite Element ◽  
Objective Function ◽  
Bending Moment ◽  
Pilot Project ◽  
Black Box ◽  
Bending Moments ◽  
Finite Element Program ◽  
Optimization Task ◽  
Element Program ◽  
The Given

The article analyzes the optimization of grillage-type foundations seeking for the least possible reactive forces in the poles for a given number of poles and for the least possible bending moments of absolute values in the connecting beams of the grillage. Therefore, we suggest using a compromise objective function (to be minimized) that consists of the maximum reactive force arising in all poles and the maximum bending moment of the absolute value in connecting beams; both components include the given weights. The variables of task design are pole positions under connecting beams. The optimization task is solved applying the algorithm containing all the initial data of the problem. Reactive forces and bending moments are calculated using an original program (finite element method is applied). This program is integrated into the optimization algorithm using the “black-box” principle. The “black-box” finite element program sends back the corresponding value of the objective function. Numerical experiments revealed the optimal quantity of points to compute bending moments. The obtained results show a certain ratio of weights in the objective function where the contribution of reactive forces and bending moments to the objective function are equivalent. This solution can serve as a pilot project for more detailed design. Santrauka Straipsnyje nagrinėjamas rostverkinių pamatų optimizavimas, siekiant kuo mažesnių reaktyvinių jėgų poliuose duotajam polių skaičiui ir kuo mažesnių absoliutiniu dydžiu lenkimo momentų sijyno jungiančiosiose sijose. Optimizavimo uždavinio tikslo funkciją sudaro didžiausia visuose poliuose atraminė reakcija ir didžiausias absoliutiniu dydžiu lenkimo momentas jungiančiosiose sijose; abu dėmenys imami su tam tikrais svoriais. Uždavinio projektavimo kintamieji yra polių padėtys po jungiančiosiomis sijomis. Optimizavimo uždavinys sprendžiamas genetiniu algoritmu, į kurio formulavimą įtraukiama išankstinė žinoma informacija apie uždavinį. Reakcijų ir momentų skaičiavimo uždavinys skaičiuojamas baigtinių elementų metodu. Ši programa jungiama prie optimizavimo algoritmo juodosios dėžės principu. Optimaliam taškų, kuriuose skaičiuojami lenkimo momentai, skaičiui nustatyti atliekami skaitiniai eksperimentai. Skaitiniais eksperimentais nustatytos sąlygos, kurioms esant reakcija ir momentas turi ekvivalentišką įtaką tikslo funkcijai. Tokie skaičiavimai galėtų būti kaip bandomieji sprendiniai detaliau projektuojant sijyną.

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