Separation Characteristics of an X65 Linepipe Steel From Laboratory-Scale to Full-Scale Fracture Tests

Author(s):  
Bradley J. Davis ◽  
Guillaume Michal ◽  
Cheng Lu ◽  
Valerie Linton

Abstract Separations are small fissures that form along the rolling-plane of some steels when sufficient stresses are created to open planes of weakness in the material. In the pipeline industry, separations have been observed on the fracture surfaces of tensile, Charpy, and drop-weight tear tests — the key tests for determining the fracture arrest capabilities of line pipe steels. When compared, the separation appearance between lab-scale tests and full-scale fracture test are noticeably dissimilar. Therefore, the influence separations have on the fracture behaviour may not clearly scale between lab-scale and full-scale tests. In this study, the separation severity of Charpy, DWTT, and full-fracture propagation test fracture surfaces was measured and compared. Two full-scale burst tests were carried out with pipes containing a CO2/N2 mixture. Fracture surfaces were observed along the length of the pipe and captured when the separation appearance changed. For each pipe section, the corresponding lab-scale test surfaces were compared. With the separations measured across all fracture faces, the separation appearance of the full-scale test surfaces did not provide the same values as the lab-scale tests. However, the lab-scale tests did capture the trend in separation severity for each pipe section. Only the lab-scale test surfaces showed a correlation in separation severity.

Author(s):  
Igor Pyshmintsev ◽  
Alexey Gervasyev ◽  
Victor Carretero Olalla ◽  
Roumen Petrov ◽  
Andrey Arabey

The microstructure and fracture behavior of the base metal of different X80 steel line pipe lots from several pipeline projects were analyzed. The resistance of the pipes to ductile fracture propagation was determined by the full-scale burst tests. The high intensity of fracture surface separation (secondary brittle cracks parallel to the rolling plane of the plate) appeared to be the main factor reducing the specific fracture energy of ductile crack propagation. A method for quantitative analysis of microstructure allowing estimation of the steel’s tendency to form separations is proposed. The procedure is based on the EBSD data processing and results in Cleavage Morphology Clustering (CMC) parameter evaluation which correlates with full-scale and laboratory mechanical test results. Two special laboratory mechanical test types utilizing SENT and Charpy test concepts for prediction of ductile fracture arrest/propagation in a pipe were developed and included into Gazprom specifications.


1974 ◽  
Vol 96 (4) ◽  
pp. 323-329 ◽  
Author(s):  
W. A. Poynton ◽  
R. W. E. Shannon ◽  
G. D. Fearnehough

Shear fracture propagation is studied using an analysis based upon the thermodynamic equilibrium of a constant velocity fracture. This equation is shown to describe the behavior of all full scale tests which exhibit constant velocity propagation. This equation is developed to identify the conditions for fracture arrest; the resulting formulation is again consistent with full scale test behavior. The paper also discusses the application of the theory to existing and new pipelines.


Author(s):  
Chris Timms ◽  
Doug Swanek ◽  
Duane DeGeer ◽  
Arjen Meijer ◽  
Ping Liu ◽  
...  

The TurkStream pipeline project is designed to transport approximately 32 billion cubic meters of natural gas annually from Russia to Turkey under the Black Sea, with more than 85% of the deep-water route being deeper than 2000 m. The offshore section is intended to consist of two parallel lines, each approximately 900 km long. The preliminary stages of the front end engineering design (pre-FEED) phase was managed by INTECSEA. To support the analyses and design of the deepest portions, a full scale collapse test program was performed by C-FER Technologies (C-FER). This collapse test program, which included 62 full-scale collapse and pressure+bend tests, 54 medium-scale ring collapse tests, and hundreds of small-scale tests, was primarily aimed at measuring, quantifying and documenting the increase in pipe strength and collapse resistance resulting from the thermal induction heat treatment effect (thermal ageing) that arises during the pipe coating process. Two grades of 32-inch (813 mm) outside diameter (OD) line-pipe, SAWL450 and SAWL485 with wall thicknesses of 39.0 mm or 37.4 mm, respectively, were supplied from various mills for testing. The collapse test program objectives were as follows: • Determine the collapse resistance of line pipes originating from various pipe mills; • Determine the pressure+bend performance of line pipes originating from various pipe mills; • Measure the effect of thermal ageing on material and collapse testing results, including the impact of multiple thermal cycles; and • Evaluate the results of medium-scale ring collapse tests as compared to full-scale tests. This paper presents selected results of this work, along with some comparisons to predictive equations.


2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Chung-Won Lee ◽  
Jiseong Kim ◽  
Gi-Chun Kang

Vibration and noise problems caused by a number of construction processes, specifically blasting for infrastructure development, are becoming important because of their civil appeal. In this study, a square root equation (SRE) with a 95% confidence level was proposed for predicting blasting-induced vibration through full-scale test blasting, and the vibration value predicted from this equation was located between the values predicted from the USBM (US Department of Interior, Bureau of Mines), NOF (Nippon Oil & Fats Co., Ltd.), and MCT (Ministry of Construction and Transportation) equations. Additionally, by comparing the measured noise level at full-scale test blasting with the calculated noise levels from several noise prediction equations, it was determined that the noise level predicted by the ONECRC equation had the best agreement with the measured results. However, in cases where blasting includes tunnel excavation, simultaneous measurement of vibration and noise is required to prevent damage to the surrounding facilities.


Author(s):  
Mitsuhiro Miyamoto ◽  
Haruka Okuhiro

In the present study, few studies have focused on the horizontal plane of traditional wooden houses in Japan. This study aims to examine the retrofit effects for the horizontal plane of traditional wooden houses based on full-scale tests. The first part of this paper is devoted to the experimental study performed to determine the structural behavior and characteristics of full-scale roof specimens. A horizontal shear test was conducted to obtain the fracture mode and relationship between the applied load and deformation angle. The second part deals with a static pushover analysis of the full-scale roof specimens. The results between the experimental test and the static pushover analysis are presented and discussed. The analysis model used for the static pushover analysis is proposed; the results were in good agreement with the tests.


Author(s):  
Claudio Somaschini ◽  
Tommaso Argentini ◽  
Daniele Rocchi ◽  
Paolo Schito ◽  
Gisella Tomasini

The resistance to motion of trains is an essential requisite especially while designing high-speed trains and high-capacity railway lines. The optimisation of friction effects and aerodynamic performance can be done during the design stage of a new train but the actual value of the running resistance can be inferred only by means of full-scale tests during the operation of a train. A CEN standard (EN 14067-4) describes the methodologies for the assessment of the running resistance of railway vehicles starting from full-scale test measurements. According to this standard, the speed-dependent terms of the resistance force have to be determined by means of coasting tests on railway lines, whose characteristics must be well known. Since this is not always possible and small errors on the gradient could lead to major uncertainties in the evaluation of the resistance force, a new method for the estimation of the running resistance coefficients, irrespective of the characteristics of the track is proposed in this paper. The reliability of the method is verified by comparing the results with those obtained from the procedure proposed in the CEN standard. The comparison shows that the new methodology is able to evaluate the resistance coefficients with an accuracy equivalent to that of the other methods but with fewer tests and with a more robust procedure relying on a lesser number of parameters.


Author(s):  
Wei Wang ◽  
Marina Q. Smith ◽  
Carl H. Popelar ◽  
James A. Maple

It is commonly believed that bending and other secondary loading will reduce the rupture pressure of a corroded pipe. This paper shows through theory, full-scale tests and finite element analysis (FEA) that this need not be the case in the field where displacement controlled bending and axial loading are induced by differential settlement and axial constraint. Based on this result, a new strain-based rupture prediction model is developed for buried corroded pipes subjected to internal pressure, lateral bending, thermal loading and residual stress. The selection of an appropriate “bulging factor,” the determination of a biaxial strain limit and the treatment of the heat affected zone (HAZ) are also discussed in the paper. The predicted rupture pressures agree well with the full-scale test results.


2018 ◽  
Vol 18 (09) ◽  
pp. 1850109 ◽  
Author(s):  
Li Tian ◽  
Liulu Guo ◽  
Ruisheng Ma ◽  
Xia Gai ◽  
Wenming Wang

Full-scale tests are conducted to investigate the load-bearing capacity and failure mechanism of power transmission towers subjected to various loading patterns (broken lines, wind and ice). Detailed finite element models of power transmission towers are established based on these experimental prototypes. To capture the member instability, the integral stability coefficients are obtained from different specifications and introduced into a user-defined material model. Subsequently, the failure analysis of power transmission towers is carried out using an explicit algorithm, and good agreement is found in comparison with experimental results. The results show that the proposed procedure is effective in simulating the power transmission tower failure process. The full-scale test and numerical simulation studies can provide a valuable database for the design of power transmission towers subjected to various loads.


1965 ◽  
Vol 87 (3) ◽  
pp. 265-278 ◽  
Author(s):  
G. M. McClure ◽  
A. R. Duffy ◽  
R. J. Eiber

The program of research on line pipe under the sponsorship of the A.G.A. Pipeline Research Committee is a comprehensive effort to investigate the important properties of pipe used in gas transmission. Several different phases are involved in this project, ranging from fundamental laboratory studies to fracture-behavior experiments on large-diameter pipe. This paper discusses the full-scale experimental parts of the program in which the fracture toughness of line pipe is being studied. Some of the factors that influence full-scale fracture behavior are discussed—material properties, fracture speed, temperature, wall thickness, nominal stress level, and type of backfill. Laboratory fracture tests that are being run and correlated with full-scale behavior are also described.


Author(s):  
Anand Prabhakaran ◽  
Francisco González

Railroad tank car top fittings are susceptible to damage and failure in rollover derailments, which might result in release of hazardous material lading. Prior research has focused on the susceptibility of fittings on non-pressure tank cars and potential mitigation strategies. This paper presents current work that extends the analysis/test methods and lessons learned to fittings on pressure tank cars. Pressure tank cars carry significantly more hazardous materials such as Chlorine and Anhydrous Ammonia, which are classified as Toxic Inhalation Hazards (TIH). In particular, this paper presents the results of analytical modeling and validation testing of top fittings on a base design Chlorine car. In addition, the paper compares and contrasts the test methodology employed in prior full scale tests of tank car fittings against the 9 mph evaluation scenario outlined in current Federal regulations governing the design of fittings on TIH tank cars, and further explores how full scale test results may be interpreted.


Sign in / Sign up

Export Citation Format

Share Document