Investigation of Crack Propagation Characteristics Using Instrumented Charpy and DWT Tests for Full-Scale Burst Tested 1219 mm OD Grade 550 (X80) Linepipe

2016 ◽  
Author(s):  
Satoshi Igi ◽  
Cindy Guan ◽  
Brian Rothwell ◽  
Takashi Hiraide
Keyword(s):  
Crack Propagation ◽  
High Speed ◽  
Large Diameter ◽  
Propagation Speed ◽  
Test Site ◽  
Management Program ◽  
Full Scale ◽  
In Situ Observation ◽  
Separation Index ◽  
Crack Propagation Speed

TransCanada, on behalf of the Coastal GasLink (CGL) project, has carried out two full-scale burst tests [1, 2] at the Spadeadam test site of DNV GL, to validate the effectiveness of crack arrestors and refine the propagation control design for the large-diameter, X80 linepipe required for this project. The tests were supported by LNG Canada and TransCanada Technology Management Program. For these full-scale burst tests, Grade 550linepipe having Charpy energies from 125 to over 450 J were produced using thermomechanical controlled processing (TMCP) technology. This paper describes propagation and arrest properties of the X80 linepipe materials having various Charpy energy values from the aspect of crack propagation energy and crack propagation speed relationships from instrumented Charpy and press-notched (PN) and static pre-cracked drop-weight tear (SPC-DWT) tests, together with in-situ observation of crack propagation by high-speed video camera. It was found that crack propagation speed is greatly affected by crack propagation energy measured by both Charpy and instrumented DWT tests. The crack propagation energy is lower in DWTT specimens with a higher separation index. It is not clear whether the crack propagation energy is only affected by the separations. However, the crack velocity is higher in DWTT specimens with a higher separation index. It is assumed that the crack propagation speed might be not only affected by separation but also low propagation energy. The testing data obtained from Charpy and instrumented DWT tests are compared with the fracture speed data measured from the full-scale burst test. The correlation between Charpy energy and crack propagation energy in DWTT is also compared with the predictions of an empirical equation.

scholarly journals Arctic Linepipe With High Resistance to Crack Propagation and HIC

1996 ◽  
Author(s):  
Gregorio R. Murtagian ◽  
Guillermo L. Fitzsimons ◽  
Juan C. González ◽  
Irina S. Kotova ◽  
Nikoli I. Anenkov
Keyword(s):  
Crack Propagation ◽  
Large Diameter ◽  
Propagation Speed ◽  
Unstable Crack ◽  
Computer Data ◽  
Computer Data Acquisition ◽  
Hydrogen Induced Cracking ◽  
Crack Propagation Speed ◽  
Linepipe Steels ◽  
Work Done

Linepipe steels for sour, arctic and offshore applications, form a class of material by themselves. These linepipes are originated in the need to fulfill several special characteristics like adequacy for induction bending, toughness requirement at very low temperature to prevent a unstable crack propagation, and hydrogen induced cracking resistance. These kind of linepipes are produced through clean steel practice, resulting in a low residuals content and a low non metallic inclusions rating. It is also very important to get a fine and uniform microstructure to guarantee good performance under sour environments, arctic and offshore conditions. In the present paper, a practical test to assess fitness for service of special linepipes is presented. Two linepipes with diameters between 219 and 273 mm and Diameter/thickness (D/t) ratios from 10 to 20, intended for arctic service were studied. While linepipe of both large Diameter and D/t (above 50), have been studied, there has been very little work done for diameters below 420 mm and D/t ratios in the range of 10–20. Full scale burst tests at −40°C and −60°C were carried out under controlled conditions. Actual crack propagation speed during burst tests at temperatures below −60°C, was tracked through an oscilloscope-computer data acquisition system. Weldability and hydrogen induced cracking performances were also studied.

Changes in the mechanical properties of snow relevant to crack propagation in the hours and minutes following loading

2020 ◽  
Author(s):  
Karl W. Birkland ◽  
Bastian Bergfeld ◽  
Alec van Herwijnen
Keyword(s):  
Mechanical Properties ◽  
Crack Propagation ◽  
High Speed ◽  
Propagation Speed ◽  
Temporal Changes ◽  
Image Correlation ◽  
Additional Information ◽  
The Hours ◽  
Crack Propagation Speed ◽  
Specific Fracture

<p>Since most dry slab avalanches occur during or immediately following loading by snowfall or wind deposition, it is important to understand changes in the mechanical properties of the snowpack in the minutes and hours following loading. To investigate these temporal changes we conducted a series of 15 Propagation Saw Test (PST) experiments on a flat, uniform site. The existing snowpack at our site contained a layer of surface hoar buried 2 cm below the snow surface. We used a 5 mm sieve to add 10 cm of snow into a 120 cm by 30 cm cardboard frame and completely isolated our blocks. We then conducted PSTs on the buried surface hoar layer from 4 – 453 minutes after adding the sieved snow. We sprayed dye on the side of our tests and filmed them with a high speed camera at 3000 frames per second. Immediately following our tests we measured the density of the sieved snow, and we collected three SnowMicroPen (SMP) profiles along the length of each PST. In one case we collected SMP data at 10 cm increments along our beam prior to conducing our PST to better assess vertical and lateral variations in slab properties induced by sieving. We utilize Digital Image Correlation analyses of the high speed videos to assess the slab elastic modulus (E), the weak layer specific fracture energy (wf), and the crack propagation speed (c) of each test. All our tests fully propagated to the end of the PST columns. Critical cut lengths (rc) ranged between 1.5 and 9 cm, with rc generally increasing over time, in line with the gradual stiffening of the slab observed in the SMP measurements. Our results provide additional information about the temporal changes of mechanical properties immediately following loading, and will better inform modeling efforts attempting to assess these changes.</p>

scholarly journals Crack propagation speed in ceramic during quenching

2018 ◽  
Vol 38 (7) ◽  
pp. 2879-2885 ◽  
Author(s):  
Yingfeng Shao ◽  
Boyang Liu ◽  
Xiaohuan Wang ◽  
Long Li ◽  
Jiachen Wei ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Propagation Speed ◽  
Crack Propagation Speed

Effect of Contact between the Crack Faces on Crack Propagation

2013 ◽  
Vol 577-578 ◽  
pp. 61-64 ◽  
Author(s):  
Guido Dhondt
Keyword(s):  
Crack Propagation ◽  
Propagation Speed ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Contact Conditions ◽  
Contact Formulation ◽  
Positive Mode ◽  
Crack Propagation Speed ◽  
Crack Faces ◽  
Realistic Prediction

In mixed-mode crack propagation the crack faces frequently touch each other. The ensuing friction is expected to decrease the crack propagation speed. This effect is usually not taken into account, however, a realistic prediction of this effect may increase the calculated life and consequently increase the length of the inspection intervals. In this paper, penalty contact conditions are introduced in between the crack faces of the automatically generated mesh in a cyclic crack propagation. Special attention is given to the contact formulation and the area in which contact is defined. It is shown that the resulting crack propagation rate is significantly reduced by the introduction of friction provided that positive Mode-I is not significantly involved.

scholarly journals Determination of Some Frozen and Thawed Properties of Permafrost Soils

1973 ◽  
Vol 10 (4) ◽  
pp. 592-606 ◽  
Author(s):  
G. H. Watson ◽  
W. A. Slusarchuk ◽  
R. K. Rowley
Keyword(s):  
Sample Preparation ◽  
Large Diameter ◽  
Test Site ◽  
Full Scale ◽  
Laboratory Methods ◽  
Predictive Methods ◽  
Permafrost Soils ◽  
Pipe Line ◽  
Ice Content

Mackenzie Valley Pipe Line Research Limited has undertaken a significant amount of full-scale testing at its test site near Inuvik, N.W.T. Large diameter high ice content permafrost core samples were taken from this site to controlled laboratory conditions, and tested in both frozen and thawed states so that proposed predictive methods for pipeline performance could be evaluated.This paper describes procedures for sampling, sample transportation at controlled temperatures, and sample preparation in the laboratory. Methods for thaw-settlement and thaw-strength are also described. The results of these tests are presented and analyzed.

Simulation of Dynamic Crack Propagation and Arrest Using Various Types of Crack Arrestor

2016 ◽  
Author(s):  
Mohammed Uddin ◽  
Gery Wilkowski
Keyword(s):  
Crack Propagation ◽  
Large Diameter ◽  
Small Diameter ◽  
Full Scale ◽  
Fe Model ◽  
Ductile Crack ◽  
Burst Test ◽  
Ductile Crack Growth ◽  
Diameter Pipe ◽  
Linepipe Steels

In linepipe steels, there has been a growing interest in using damage mechanics that provides physical models of the fracture process which are embedded into a two- or three-dimensional finite element (FE) model. Among the various damage models, the cohesive zone model (CZM) has recently been used to simulate the ductile crack growth behavior in linepipe steels because of its computational efficiency and it requires only two parameters which can be determined in experiments. While CZM is not yet to be used as predictive tool, but it has a great application in crack arrestor design as well as in providing insight to ductile crack propagation. In this paper, the authors have demonstrated some practical applications of CZM in linepipe steels. The CZM was used to simulate the ductile crack propagation in full-scale pipes which was able to capture the global deformation as well as the experimental crack speed. The model was then used to determine the effect of anchor blocks at the end of the pipe in a large diameter full-scale burst test. Later, the model was used to simulate two small diameter pipe tests with steel crack arrestors to mimic two arrestor cases with one showing crack propagation and the other showing crack arrest. The CZM model was also applied to demonstrate the circumferential ring-off behavior of a small diameter pipe test with rigid crack arrestor. The arrestor model was then extended to simulate a large diameter full scale Mojave burst test with “soft crack arrestor (SCA)”. A single element FE model was developed to verify the SCA material which was later extended with stain-based failure criteria. Finally, ductile crack growth in full-scale pipe with SCA was demonstrated to show that the FE CZM model can be used to optimize the design of SCA.

Development of a Pipe Rupture

1988 ◽  
Vol 110 (4) ◽  
pp. 451-456
Author(s):  
T. R. Best
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Crack Propagation ◽  
Liquid Water ◽  
Propagation Speed ◽  
Pipe Failure ◽  
Subcooled Liquid ◽  
Reaction Forces ◽  
Crack Propagation Speed

An approach to the problem of predicting reaction forces that can occur during pipe failure is provided. Use is made of experimental data measuring crack propagation speed to determine the pipe rupture forces. The results of this paper are for pipelines carrying subcooled liquid water, but may be applied to other fluids. The reaction forces during pipe failure are compared with steady-state values.

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