Testing of Segment Specimens and Full Scale Pipes for the Assessment of Fracture During Reeling Installation

2004 ◽  
Author(s):  
Stig Wa¨stberg
Keyword(s):  
Stable Crack Growth ◽  
Full Scale ◽  
Fusion Line ◽  
Materials Testing ◽  
Strain Development ◽  
Guideline Document ◽  
Fracture Control ◽  
Cyclic Plastic Strain ◽  
Bending Loading ◽  
Good Agreement

This Paper describes the testing of Segment Specimens and Full Scale Pipes carried out at DNV within the Joint Industry Project “Fracture Control for Installation Methods Introducing Cyclic Plastic Strain – Development of Guidelines for Reeling of Pipelines”. The JIP was a cooperation between DNV, TWI and Sintef. A total of 24 full thickness Segment Specimens, with cracks/notches introduced in the Base Metal, Fusion Line Root and Fusion Line Cap, were tested. The specimens were loaded both monotonically and cyclically, simulating reeling installation. Two Full Scale Pipes were subjected to a bending loading program simulating a reeling installation. Each pipe contained three test welds and cracks/notches were introduced both at the 6 o’clock and the 12 o’clock positions, i.e. six cracks/notches in each pipe. In one pipe the cracks/notches were introduced in the Weld Metal and in the other in the Fusion Line from the Cap side. After the loading program all the cracks/notches were broken open and the stable crack growth were measured and compared to predictions based on fracture mechanics principals (essentially following BS 7910-1999). A method for adjusting the analysis procedure, in order to obtain good agreement between the predictions and the experimental observations, is suggested. The JIP also included Materials Testing and FEM Analyses. A Guideline Document was developed which is currently being used by the project participants and it is the intention to issue a DNV Recommended Practice in support of the DNV Offshore Standard OS-F101 “Submarine Pipeline Systems – 2000” based on the experience gained and feed back received from the participants. The Guideline document is described in another paper (OMAE2004-51061) at the conference.

Guidelines for Engineering Critical Assessments for Pipeline Installation Methods Introducing Cyclic Plastic Strain

2004 ◽  
Author(s):  
Stig Wa¨stberg ◽  
Henryk Pisarski ◽  
Ba˚rd Nyhus
Keyword(s):  
Plastic Strain ◽  
Materials Testing ◽  
Plastic Strains ◽  
Strain Development ◽  
Cyclic Plastic ◽  
Guideline Document ◽  
Fracture Control ◽  
Cyclic Plastic Strain ◽  
Assessment Procedures ◽  
Validation Testing

Conventional flaw assessment procedures are not explicitly developed for situations with large cyclic plastic strains, e.g. for pipelines installed by the Reeling method, and if used indiscriminately may give un-reliable results. In order to resolve this dilemma DNV, TWI and Sintef conducted a Joint Industry Project (Fracture Control for Installation Methods Introducing Cyclic Plastic Strain – Development of Guidelines for Reeling of Pipelines) to provide guidelines on testing and assessment procedures that can be employed by the industry. The project included Materials Testing, FEM Analyses and Validation Testing of Pipe Segments as well as Full Scale Pipes. This paper summarizes the Guideline document that was developed in the project.

scholarly journals Stable Crack Growth of Surface Crack across the Fusion Line.

1992 ◽  
Vol 58 (556) ◽  
pp. 2254-2259
Author(s):  
Masanori KIKUCHI ◽  
Kenji MACHIDA ◽  
Kenji OOKI
Keyword(s):  
Crack Growth ◽  
Surface Crack ◽  
Stable Crack Growth ◽  
Fusion Line

Examination of the Transferability of CTOA From Small-Scale DWTT to Full-Scale Pipe Geometries Using a Cohesive Zone Model

2020 ◽  
Author(s):  
Chris Bassindale ◽  
Xin Wang ◽  
William R. Tyson ◽  
Su Xu
Keyword(s):  
Finite Element ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Element Model ◽  
Full Scale ◽  
Opening Angle ◽  
Small Scale ◽  
Zone Model ◽  
Pipe Model ◽  
Good Agreement

Abstract In this work, the cohesive zone model (CZM) was used to examine the transferability of the crack tip opening angle (CTOA) from small-scale to full-scale geometries. The pipe steel STPG370 was modeled. A drop-weight tear test (DWTT) model and pipe model were studied using the finite element code ABAQUS 2017x. The cohesive zone model was used to simulate crack propagation in 3D. The CZM parameters were calibrated based on matching the surface CTOA measured from a DWTT finite element model to the surface CTOA measured from the experimental DWTT specimen. The mid-thickness CTOA of the DWTT model was in good agreement with the experimental value determined from E3039 and the University of Tokyo group’s load-displacement data. The CZM parameters were then applied to the pipe model. The internal pressure distribution and decay during the pipe fracture process was modeled using the experimental data and implemented through a user-subroutine (VDLOAD). The mid-thickness CTOA from the DWTT model was similar to the mid-thickness CTOA from the pipe model. The average surface CTOA of the pipe model was in good agreement with the average experimental value. The results give confidence in the transferability of the CTOA between small-scale specimens and full-scale pipe.

STUDY ON RETROFIT EFFECTS FOR HORIZONTAL PLANE OF TRADITIONAL WOODEN HOUSES BASED ON FULL-SCALE TEST

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Mitsuhiro Miyamoto ◽  
Haruka Okuhiro
Keyword(s):  
Horizontal Plane ◽  
Pushover Analysis ◽  
Full Scale ◽  
Horizontal Shear ◽  
Full Scale Test ◽  
Analysis Model ◽  
Scale Test ◽  
Full Scale Tests ◽  
Static Pushover Analysis ◽  
Good Agreement

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.

Analysis of stable crack growth across welded fusion line: Japanese round-robin

1993 ◽  
Vol 142 (1) ◽  
pp. 51-60
Author(s):  
M. Kikuchi ◽  
S. Yoshimura ◽  
S. Aoki ◽  
T. Nishioka ◽  
N. Nakagaki ◽  
...  
Keyword(s):  
Crack Growth ◽  
Stable Crack Growth ◽  
Round Robin ◽  
Fusion Line

Hydrodynamic Verification on the Motion Characteristics of FPSO Based on the Full Scale Measurement Data Features of Current and Wind

2010 ◽  
Author(s):  
Wenhua Zhao ◽  
Jianmin Yang ◽  
Zhiqiang Hu ◽  
Yuefeng Wei
Keyword(s):  
Time Domain ◽  
Measurement Data ◽  
Full Scale ◽  
Motion Prediction ◽  
Mooring System ◽  
Wind Force ◽  
Sea State ◽  
Hydrodynamic Analysis ◽  
Motion Characteristics ◽  
Good Agreement

FPSO is subjected to complex sea loads during its service life. Series of coupled hydrodynamic analysis in time domain for FPSO and its mooring system have been conducted within the recent ten years. Among these analyses, the coefficients of wind force and current force for FPSO hull were calculated by the empirical formulae mostly. It is known that these coefficients are of great importance in the motion predictions of the FPSO in the analysis. The verification of the feasibility of these formulae is necessary. In this paper, the feasibility and the accuracy of these empirical formulae are verified through the comparison between the results of hydrodynamic analysis and those of full scale measurement data. A full scale measurement project sponsored by CNOOC for Nanhai Fenjin, an FPSO operating in South China Sea, has been carrying out by Shanghai Jiao Tong University since Oct 2007. Large amount of valuable data of the six-degree motions for the FPSO has been obtained. To do the comparison, a typical serious sea state is selected out to be the objective course. In the course, the response spectrums for heave, roll and pitch motions are calculated based on the measurement data. Besides, a series of coupled hydrodynamic analysis for the FPSO are conducted, using the code DeepC. The response spectrums of the motions for heave, roll and pitch in the same sea state are also obtained through the spectrum analysis. Using these motion spectrums, comparisons between the results of hydrodynamic analysis and those of full scale measurement are fulfilled. With the comparisons, the feasibility of the empirical formulae of the coefficients for wind force and current force are verified. The correction coefficients are added to the empirical formulae and new hydrodynamic analysis based on the new formulae are conducted. It is shown that the new analysis results are in good agreement with those of the full scale measurement, which validated the practicability and feasibility of the modified formulae on the motion prediction of FPSO.

scholarly journals Calibration of Capacitance Diaphragm Gauges with 1333 Pa full scale by Direct Comparison to Resonant Silicon Gauge and Static Expansion System

ACTA IMEKO ◽  
2014 ◽  
Vol 3 (2) ◽  
pp. 48 ◽  
Author(s):  
Hajime Yoshida ◽  
E. Komatsu ◽  
K. Arai ◽  
M. Kojima ◽  
H. Akimichi ◽  
...  
Keyword(s):  
Expansion Method ◽  
Full Scale ◽  
Lower Pressure ◽  
Pressure Balance ◽  
Sensor Head ◽  
Thermal Transpiration ◽  
Calibration Methods ◽  
Expansion System ◽  
Good Agreement

<p>Two capacitance diaphragm gauges (CDGs) with 1333 Pa full scale, with a heated sensor head and an unheated one, respectively, were calibrated by three different methods; direct comparison to a resonant silicon gauge calibrated by a pressure balance, direct comparison to a CDG with 133 Pa full scale calibrated by a static expansion method, and the static expansion method. The calibration results of the three calibration methods show good agreement within their claimed uncertainties. Calibrated higher pressure points of CDGs by the pressure balance and lower pressure ones by the static expansion system are linearly interpolated within the calibrated uncertainty. Here, compensation of the thermal transpiration effect is important when a CDG is used with a heated sensor head.</p>

Background and New Revision of DNVGL-RP-F108

2018 ◽  
Author(s):  
Steinar Lindberg Bjerke ◽  
Jens P. Tronskar ◽  
Steven Chong ◽  
Asle Venås
Keyword(s):  
Fracture Mechanics ◽  
Extensive Experience ◽  
Cyclic Plastic ◽  
Service Testing ◽  
Fracture Control ◽  
Cyclic Plastic Strain ◽  
Girth Welds ◽  
Assessment Procedures ◽  
Cyclic Plastic Deformation ◽  
Sour Service

DNV-RP-F108 [1] was first issued in 2006. The Recommended Practice was developed to provide guidance on testing and analyses for fracture control of pipeline girth welds subjected to cyclic plastic deformation, e.g. during installation by the reeling method, but also for other situations where pipelines may be subjected to large plastic strains. The Recommended Practice was based upon a Project Guideline developed within the Joint Industry Project “Fracture Control for Installation Methods Introducing Cyclic Plastic Strain - Development of Guidelines for Reeling of Pipelines”. The new revision is based on the extensive experience and knowledge gained over the years use of the previous versions, as well as new knowledge from recent R&D projects. The main content of Appendix A of DNV-OS-F101 (now DNVGL-ST-F101) [2] have been transferred to DNVGL-RP-F108. Only the requirements relative to ECA and testing have been retained in DNVGL-ST-F101 [2]. The new revision has got a new number and new title, i.e. DNVGL-RP-F108, “Assessment of Flaws in Pipeline and Riser Girth Welds”. This paper lists the fundamental changes made in the new RP from the old Appendix A of the previous DNV-OS-F101 and discusses some of the changes, although within this paper it is not possible to cover all changes. The focus is on clarification of use of S-N versus the fracture mechanics approach for fatigue life computation, classification of fatigue sensitive welds, calculations of more accurate crack driving force by re-introduction of the plate solution, for which a new Lr,max (plastic collapse) calculation and a modified way to account for residual stresses have been specified. The RP presents new assessment procedures pertaining to use of finite element analyses for fracture mechanics assessments. A unique feature of the new RP is the guidance on sour service testing and assessments included in the Appendix C of the document to support pipeline/riser ECAs to develop flaw acceptance criteria for NDT.

How New Vintage Line-Pipe Steel Fracture Properties Differ From Old Vintage Line-Pipe Steels

2012 ◽  
Author(s):  
G. Wilkowski ◽  
D.-J. Shim ◽  
Y. Hioe ◽  
S. Kalyanam ◽  
F. Brust
Keyword(s):  
Brittle Fracture ◽  
Fracture Behavior ◽  
Pipe Steel ◽  
Full Scale ◽  
Actual Behavior ◽  
Correction Factors ◽  
Pipe Steels ◽  
Line Pipe ◽  
Line Pipe Steel ◽  
Fracture Control

Newer vintage line-pipe steels, even for lower grades (i.e., X60 to X70) have much different fracture behavior than older line-pipe steels. These differences significantly affect the fracture control aspects for both brittle fracture and ductile fracture of new pipelines. Perhaps one of the most significant effects is with brittle fracture control for new line-pipe steels. From past work brittle fracture control was achieved through the specification of the drop-weight-tear test (DWTT) in API 5L3. With the very high Charpy energy materials that are being made today, brittle fracture will not easily initiate from the pressed notch of the standard DWTT specimen, whereas for older line-pipe steels that was the normal behavior. This behavior is now referred to as “Abnormal Fracture Appearance” (AFA). More recent work shows a more disturbing trend that one can get 100-percent shear area in the standard pressed-notch DWTT specimen, but the material is really susceptible to brittle fracture. This is a related phenomenon due to the high fracture initiation energy in the standard DWTT specimen that we call “Abnormal Fracture Behavior” (AFB). This paper discusses modified DWTT procedures and some full-scale results. The differences in the actual behavior versus the standard DWTT can be significant. Modifications to the API 5L3 test procedure are needed. The second aspect deals with empirical fracture control for unstable ductile fractures based on older line-pipe steel tests initially from tests 30-years ago. As higher-grade line-pipe steels have been developed, a few additional full-scale burst tests have shown that correction factors on the Charpy energy values are needed as the grade increases. Those correction factors from the newer burst tests were subsequently found to be related to relationship of the Charpy energy values to the DWTT energy values, where the DWTT has better similitude than the Charpy test for fracture behavior (other than the transition temperature issue noted above). Once on the upper-shelf, recent data suggest that what was once thought to be a grade correction factor may really be due to steel manufacturing process changes with time that affect even new low-grade steels. Correction factors comparable to that for X100 steels have been indicated to be needed for even X65 grade steels. Hence the past empirical equations in Codes and Standards like B31.8 will significantly under-predict the actual values needed for most new line-pipe steels.

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