Applicability of Existing Fracture Initiation Models to High-Strength Steel Line Pipe

2010 ◽  
Author(s):  
Do-Jun Shim ◽  
Gery Wilkowski ◽  
Frederick Brust ◽  
David Horsley ◽  
Max Toch
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Fracture Initiation ◽  
Failure Behavior ◽  
Surface Cracks ◽  
Test Results ◽  
Fracture Criteria ◽  
Line Pipe ◽  
Steel Pipes

The original fracture criteria developed by Maxey/Kiefner for axial through-wall and surface-cracked pipes have worked well for many industries for a large variety of low strength and low toughness materials. However, newer line-pipe steels have some unusual characteristics that differ from these older materials. One example is a single test that has demonstrated that X100 line-pipe with an axial through-wall-crack can fail at pressures about 30 percent lower than predicted with commonly used analysis methods for older steels. Thus, it is essential to review the currently available models and investigate the applicability of these models to newer high-strength line pipe materials. In this paper, the available models for predicting the failure behavior of axial-cracked pipes (through-wall-cracked and external surface-cracked pipes) were reviewed. The applicability of these models to high-strength steel pipes was investigated by analyzing limited full-scale pipe fracture initiation test results and the shortcomings were identified. For both through-wall and surface cracks, the major shortcomings were related to the characterization of the material toughness, which generally leads to non-conservative predictions in the J-T analyses. The findings in this paper may be limited to the test data that was consider for this study. The requisite characteristics of a potential model were also identified.

Effects of Defect Shapes on Stress of High-Strength Steel Pipe Using FSI Method

2014 ◽  
Vol 577 ◽  
pp. 154-157
Author(s):  
Yue Cui ◽  
Hui Qing Lan ◽  
Zhao Hui Zhang ◽  
Nan Lin ◽  
Yong Ping Du
Keyword(s):  
High Strength Steel ◽  
Failure Process ◽  
High Strength ◽  
Operating Conditions ◽  
Steel Pipe ◽  
Test Results ◽  
Element Analysis ◽  
Steel Pipes ◽  
Natural Gas Transmission ◽  
Fracture Arrest

High-strength steel pipes have excellent strength but have poor fracture arrest. By finite-element analysis involving fluid-structure interaction (FSI) method, models of high-strength steel pipe with three kinds of defects (triangle, rectangle and semi-ellipse) were built to determine the concentrated stress based on the working conditions of X70 pipelines in the West-to-East Natural Gas Transmission Project, and the simulation results were compared with the field test results measured by an X-ray stress analyzer. With the same defect width (2 mm), the triangular defect (40°) had a greater influence on the concentrated stress in the pipe than rectangular and semi-elliptic defects. The results can be taken as references of the damage failure process of the defect in pipes in operating conditions as well as a theoretical basis for the fracture arrest of pipes in field operation.

scholarly journals Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strength Steel ◽  
High Strength ◽  
Tensile Tests ◽  
Reinforcing Steel ◽  
Test Results ◽  
Cross Sectional ◽  
Steel Bars

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

scholarly journals Analysis and Modification of Methods for Calculating Axial Load Capacity of High-Strength Steel-Reinforced Concrete Composite Columns

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6860
Author(s):  
Jun Wang ◽  
Yuxin Duan ◽  
Yifan Wang ◽  
Xinran Wang ◽  
Qi Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
Slenderness Ratio ◽  
High Strength ◽  
Confinement Effect ◽  
Test Results ◽  
Composite Columns ◽  
Steel Reinforced Concrete ◽  
Modified Formula

To investigate the applicability of the methods for calculating the bearing capacity of high-strength steel-reinforced concrete (SRC) composite columns according to specifications and the effect of confinement of stirrups and steel on the bearing capacity of SRC columns. The axial compression tests were conducted on 10 high-strength SRC columns and 4 ordinary SRC columns. The influences of the steel strength grade, the steel ratio, the types of stirrups and slenderness ratio on the bearing capacity of such members were examined. The analysis results indicate that using high-strength steel and improving the steel ratio can significantly enhance the bearing capacity of the SRC columns. When the slenderness ratio increases dramatically, the bearing capacity of the SRC columns plummets. As the confinement effect of the stirrups on the concrete improves, the utilization ratio of the high-strength steel in the SRC columns increases. Furthermore, the results calculated by AISC360-19(U.S.), EN1994-1-1-2004 (Europe), and JGJ138-2016(China) are too conservative compared with test results. Finally, a modified formula for calculating the bearing capacity of the SRC columns is proposed based on the confinement effect of the stirrups and steel on concrete. The results calculated by the modified formula and the finite element modeling results based on the confinement effect agree well with the test results.

Formability Characterization of 3rd Generation Advanced High-Strength Steel and Application to Forming a B-Pillar

2021 ◽  
Author(s):  
Jon Edward Gutierrez ◽  
Jacqueline Noder ◽  
Neil Paker ◽  
Jamie Bowman ◽  
Amir Zhumagulov ◽  
...  
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Advanced High Strength Steel

Experimental Study of High Temperature Performance of Steel Suspension Bridge Wires

2019 ◽  
Author(s):  
Jumari A. Robinson ◽  
Adrian Brügger ◽  
Raimondo Betti
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
High Strength Steel ◽  
Cold Working ◽  
High Strength ◽  
Suspension Bridge ◽  
Theoretical Models ◽  
Test Results ◽  
Single Wire ◽  
Steel Wires

<p>The performance of suspension bridges exposed to fire hazards is severely under-studied – so much so that no experimental data exists to quantify the safety of a suspension bridge during or after a major fire event. Bridge performance and safety rely on the integrity of the main cable and its constituent high-strength steel wires. Due to the current lack of experimental high temperature data for wires, the theoretical models use properties and coefficients from data for other types of structural steel. No other structural steel undergoes the amount of cold-working that bridge wire does, and plastic strains from cold-working can be relieved at high temperature, drastically weakening the steel. As such, this work determines the elastic modulus, ultimate strength, and general thermo-mechanical profile of the high-strength steel wires in a range of elevated temperature environments. Specifically, these tests are conducted on a bundle of 61-wires (transient), and at the single wire level (steady-state) at a temperature range of approximately 20-700°C. The test results show an alarmingly high reduction in the elastic modulus and ultimate strength with increased temperature. The degradation shown by experiments is higher than predicted by current theoretical models, indicating that use of high-temperature properties of other types of steel is not sufficient. The test results also show scaling agreement between the single wire and the 61-wire bundle, implying that a full material work up at the single- wire level will accurately inform the failure characterization of the full cable.</p>

The Practical Application of Fracture Control to Natural Gas Pipelines

2008 ◽  
Author(s):  
K. A. Widenmaier ◽  
A. B. Rothwell
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
High Strength ◽  
Fracture Initiation ◽  
Opening Angle ◽  
Pipe Material ◽  
Design Factor ◽  
Line Pipe ◽  
Natural Gas Pipelines ◽  
Crack Tip Opening

The use of high strength, high design-factor pipe to transport natural gas requires the careful design and selection of pipeline materials. A primary material concern is the characterization and control of ductile fracture initiation and arrest. Impact toughness in the form of Charpy V-notch energies or drop-weight tear tests is usually specified in the design and purchase of line pipe in order to prevent large-scale fracture. While minimum values are prescribed in various codes, they may not offer sufficient protection in pipelines with high pressure, cold temperature, rich gas designs. The implications of the crack driving force arising from the gas decompression versus the resisting force of the pipe material and backfill are examined. The use and limitations of the Battelle two-curve method as the standard model are compared with new developments utilizing crack-tip opening angle and other techniques. The methodology and reasoning used to specify the material properties for line pipe are described and the inherent limits and risks are discussed. The applicability of Charpy energy to predict ductile arrest in high strength pipes (X80 and above) is examined.

scholarly journals Low temperature tensile properties of line pipe steels

2015 ◽  
Vol 6 (3) ◽  
pp. 8
Author(s):  
Harold Tubex ◽  
Koen Van Minnebruggen ◽  
Wim De Waele
Keyword(s):  
Tensile Properties ◽  
Low Temperatures ◽  
Oil And Gas ◽  
High Strength ◽  
The Arctic ◽  
Test Results ◽  
Pipe Steels ◽  
Line Pipe ◽  
Expected Increase ◽  
Strength And Ductility

Given the expected increase in Arctic oil and gas exploitation, there is a demand for high-strength line pipe steels able to cope with the Arctic climate. The state-of-the-art of the tensile properties of API 5L steels at low temperatures is reviewed and discussed. Well-known characteristics such as an increase in strength and Young’s modulus with decreasing temperatures are confirmed. The Y/T ratio is fairly unaffected by changes in temperature. Lüders elongation manifests itself at low temperatures where the Lüders plateau tends to increase. Conflicting statements about the relation between ductility and temperature were found. Altogether, quantifiable test results are scarce, especially for the high strength grades from API 5L X90 grade onwards. The urgent need for more tensile strength and ductility data of these steels at low temperatures is stated and defended.

Effect of Welding Residual Stress and Plastic Constraint on Brittle Fracture of a High Strength Steel

2009 ◽  
Author(s):  
Masaki Torigoe ◽  
Yoichi Yamashita ◽  
Takehisa Yamada
Keyword(s):  
Residual Stress ◽  
Brittle Fracture ◽  
High Strength Steel ◽  
Crack Tip ◽  
High Strength ◽  
Fracture Initiation ◽  
Parent Material ◽  
Welding Residual Stress ◽  
Cross Sectional ◽  
Plastic Constraint

This paper investigates the effect of welding residual stress and plastic constraint on brittle fracture of a 780 MPa class high-strength steel (HT780). In order to investigate the effect of welding residual stress, three point bend (3PB) fracture toughness tests were conducted using the parent-material specimens and groove-welded specimens which were prepared to have the same cross-sectional proportion; i.e., a ratio of thickness to width of 0.5. Crack length was determined so that the crack tip was located in the base-metal zone far from the heat-affected zone of the welded specimen to eliminate the effect of any degradation of the parent-material property on fracture resistance. Also, in order to investigate the effect of constraint, tensile loading tests in which the plastic constraint was expected to be less than 3PB were conducted using welded specimens as the same as employed in the 3PB test. Three dimensional finite element (FE) analyses were performed to evaluate the stress state near the crack tip at the point of brittle fracture initiation for each test condition. From the results of experiments and FE analyses, it is confirmed that the fracture test results can be evaluated using J or KJ – Q theory, by considering enhancement or reduction due to residual stress.

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