A Comparison of Fracture Mechanics and S–N Curve Approaches in Designing Drill Pipe

1992 ◽  
Vol 114 (3) ◽  
pp. 205-211 ◽  
Author(s):  
A. Ertas ◽  
G. Mustafa ◽  
O. Cuvalci
Keyword(s):  
Fracture Mechanics ◽  
Fatigue Damage ◽  
Drill Pipe ◽  
Ball Joint ◽  
Marine Riser ◽  
Deep Drilling ◽  
Miner’S Rule ◽  
Miner's Rule ◽  
Total Damage ◽  
Dynamic Fatigue

It is well known that the upper ball joint in a marine riser, in deep drilling, can cause fatigue damage in the drill pipe passing through it. A study of fracture mechanics and S–N curve approaches has been undertaken to determine the dynamic fatigue damage in the drill pipe. Miner’s rule is utilized in both methods to determine the total damage. The results of both methods are compared.

The Effect of Tool Joint Stiffness on Drill Pipe Fatigue in Riser Ball Joints

1989 ◽  
Vol 111 (4) ◽  
pp. 369-374 ◽  
Author(s):  
A. Ertas ◽  
W. R. Blackstone ◽  
B. K. Majumdar
Keyword(s):  
Fatigue Damage ◽  
Joint Angle ◽  
Drill Pipe ◽  
Joint Stiffness ◽  
Finite Element Models ◽  
Ball Joint ◽  
Marine Riser ◽  
Joint Angles ◽  
Ball Joints ◽  
Tool Joint

It is well known that the ball joint in a marine riser can cause fatigue damage in the drill pipe passing through. Previous investigators have assessed the damage done for a lower ball joint angle of 3–5 degrees (drilling) and 1–3 degrees (running casing). This paper extends that work to deep water operations in which an upper ball joint is also present. Also, it is shown, via finite element models, that tool joint bending stiffness can have a significant effect on fatigue life. Fatigue damage calculations, including this heretofore unconsidered effect, are presented for various ball joint angles and drill pipe tensions.

Fatigue Testing of Full Scale Girth Welded Pipes Under Variable Amplitude Loading

2012 ◽  
Author(s):  
Y.-H. Zhang ◽  
S. J. Maddox
Keyword(s):  
Fatigue Limit ◽  
Fatigue Damage ◽  
Fatigue Testing ◽  
Full Scale ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Fatigue Design ◽  
Miner’S Rule ◽  
Miner's Rule ◽  
Loading Spectrum

In the fatigue design of steel catenary risers there are concerns regarding the fatigue damage to girth welds from low stresses, below the constant amplitude fatigue limit, in the loading spectrum and the validity of Miner’s cumulative damage rule. In both cases there is increasing evidence that current design methods can be non-conservative. These fundamental issues were addressed in a recent JIP. A key feature was development of the resonance fatigue testing rigs to enable them to test full-scale pipes under variable amplitude loading. Such tests were performed under a loading spectrum representative of that experienced by some risers, with many tests lasting over 100 million cycles to investigate the fatigue damage due to small stresses as well as the validity of Miner’s rule. However, the resonance rigs are only capable of producing spectrum loading by gradually increasing or decreasing the applied load, whereas more ‘spiky’ random load sequences may be relevant in practice. Therefore the programme also included fatigue tests in conventional testing machines on strip specimens cut from pipes to compare the two types of loading sequence. This paper presents the results of these tests, conclusions drawn and recommendations for changes to current fatigue design guidance for girth welded pipes regarding the definition of the fatigue limit, allowance for the damaging effect of low stresses and the validity of Miner’s rule.

A Statistical Simulation Model of Miner’s Rule

1981 ◽  
Vol 103 (2) ◽  
pp. 112-117 ◽  
Author(s):  
S. E. J. Johnsen ◽  
M. Doner
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Simulation Model ◽  
Fatigue Damage ◽  
Room Temperature ◽  
Statistical Simulation ◽  
Miner’S Rule ◽  
Cumulative Fatigue Damage ◽  
Miner's Rule ◽  
Monte Carlo Simulation Model

A Monte Carlo simulation model of the classical Miner’s rule for cumulative fatigue damage is devised and implemented for an example of three summands. Results from the simulation are compared with Miner’s rule. The concept of damage-sum-to-failure is developed and applied to measured values of INCO 901 at room temperature.

The Fatigue Behavior of Steel Structures under Random Loading

2008 ◽  
Vol 378-379 ◽  
pp. 3-16
Author(s):  
Henning Agerskov
Keyword(s):  
Fracture Mechanics ◽  
Fatigue Test ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Test Series ◽  
Test Results ◽  
Random Loading ◽  
Mechanics Analysis ◽  
Miner’S Rule ◽  
Miner's Rule

Fatigue damage accumulation in steel structures under random loading has been studied in a number of investigations at the Technical University of Denmark. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part of the investigation, fatigue test series with a total of 540 fatigue tests have been carried through on various types of welded plate test specimens and full-scale offshore tubular joints. The materials that have been used are either conventional structural steel or high-strength steel. The fatigue tests and the fracture mechanics analyses have been carried out using load histories, which are realistic in relation to the types of structures studied, i.e. primarily bridges, offshore structures and chimneys. In general, the test series carried through show a significant difference between constant amplitude and variable amplitude fatigue test results. Both the fracture mechanics analysis and the fatigue test results indicate that Miner’s rule, which is normally used in the design against fatigue in steel structures, may give results, which are unconservative, and that the validity of the results obtained from Miner’s rule will depend on the distribution of the load history in tension and compression.

Fatigue Testing of Full Scale Girth Welded Pipes Under Variable Amplitude Loading

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Y.-H. Zhang ◽  
S. J. Maddox
Keyword(s):  
Fatigue Limit ◽  
Fatigue Damage ◽  
Fatigue Testing ◽  
Full Scale ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Fatigue Design ◽  
Miner’S Rule ◽  
Miner's Rule ◽  
Loading Spectrum

In the fatigue design of steel catenary risers, there are concerns regarding the fatigue damage to girth welds from low stresses, below the constant amplitude fatigue limit, in the loading spectrum and the validity of Miner's cumulative damage rule. These fundamental issues were addressed in a recent joint-industrial project (JIP). A key feature was development of the resonance fatigue testing rigs to enable them to test full-scale pipes under variable amplitude loading. Such tests were performed under a loading spectrum representative of that experienced by some risers, with many tests lasting over 100 million cycles to investigate the fatigue damage due to small stresses as well as the validity of Miner's rule. However, the resonance rigs are only capable of producing spectrum loading by gradually increasing or decreasing the applied load whereas more “spiky” random load sequences may be relevant in practice. Therefore, the program also included fatigue tests in conventional testing machines on strip specimens cut from pipes to compare the two types of loading sequence. This paper presents the results of these tests, conclusions drawn, and recommendations for changes to current fatigue design guidance for girth welded pipes regarding the definition of the fatigue limit, allowance for the damaging effect of low stresses, and the validity of Miner's rule.

Loading Sequence Effects on Fatigue Damage Accumulation of Offshore Structures: A Deterministic Approach

2017 ◽  
Author(s):  
Dimitrios G. Pavlou
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Damage ◽  
Mixed Mode ◽  
Fatigue Crack Initiation ◽  
Offshore Structures ◽  
Fatigue Damage Accumulation ◽  
Miner’S Rule ◽  
Miner's Rule

Offshore structures are subjected to irregular loading spectra due to their exposure to waves and wind. The environmental loads cause variable amplitude stress histories on critical spots of the structures. The existing engineering methodology (adopted by most of the national standards) to estimate the accumulated fatigue damage is based on Miner’s rule for crack initiation. Paris rule and its modifications are used for crack propagation prediction. However, Miner’s rule is a linear model and does not take into account the sequence effect of loading blocks with different stress amplitude. On the other hand, the widely used Paris rule does not take into account the load interaction effects (e.g. overload-induced crack growth retardations). The prediction of the crack growth rate and the crack growth direction of mixed mode cracks is an important issue as well. Aim of the present paper is the analysis of the weaknesses of the engineering tools for fatigue analysis, and the demonstration of the advantages of non-linear damage functions and crack propagation models. A review of models for fatigue crack initiation and growth (for mode I or mixed mode loading) developed by the author is presented. Representative results are discussed and commented.

Fatigue Life Assessment for Variable Strain in a Mixing Tee by Use of Effective Strain Range

2021 ◽  
Author(s):  
Koji Miyoshi ◽  
Masayuki Kamaya
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Fatigue Damage ◽  
Hot Spot ◽  
Effective Strain ◽  
Strain Range ◽  
Life Assessment ◽  
Miner’S Rule ◽  
Loading Sequence ◽  
Miner's Rule

Abstract Mixing flow causes fluctuations in fluid temperature near a pipe wall and may result in fatigue crack initiation. Movement of the hot spot, at which the pipe inner surface was heated by hot flow from the branch pipe, causes thermal stress fluctuations. In this study, the effect of the loading sequence on thermal fatigue in a mixing tee was investigated. In addition, the prediction method of the fatigue life for the variable thermal strain in the mixing tee was discussed. The time histories of the strain around the hot spot were estimated by finite element analysis for which the temperature condition was determined by wall temperature measured in a mock-up test. The accumulated fatigue damage around the hot spot obtained by Miner's rule was less than 1.0. Since the strain around the hot spot had waveforms with periodic overload, the loading sequence with periodic overload caused reduction of the fatigue life around the hot spot. Crack growth tests showed that a single overload decreased crack opening strain and increased the effective strain range. The increment of the effective strain range accelerated the crack growth rate after the overload. The accumulated fatigue damage for the strain in the mixing tee was calculated using Miner's rule and the strain ranges which added the maximum increment of the effective strain range. The accumulated fatigue damage was larger than 1.0 under most conditions. The proposed procedure is suitable to predict the conservative fatigue life in a mixing tee.

Variable Loading Sequence Effect for Thermal Fatigue at a Mixing Tee

2019 ◽  
Author(s):  
Koji Miyoshi ◽  
Masayuki Kamaya
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Pipe Wall ◽  
Hot Spot ◽  
Fatigue Tests ◽  
Stress Fluctuation ◽  
Fluctuation Range ◽  
Miner’S Rule ◽  
Loading Sequence ◽  
Miner's Rule

Abstract Mixing flow causes fluctuations in fluid temperature near the pipe wall and may result in fatigue crack initiation. In a previous study, the authors reported the characteristics of the thermal stress to cause thermal fatigue at a mixing tee. A large stress fluctuation was caused by movement of the hot spot, at which the pipe wall was heated by hot flow from the branch pipe. According to a general procedure, fatigue damage is calculated by the linear damage accumulation rule. However, it has been reported that Miner’s rule does not always predict the fatigue life conservatively for variable stress amplitude. In this study, we investigated the change in fatigue life due to variable strain around the hot spot. The time histories of the strain around the hot spot were estimated by finite element analysis (FEA) for which the temperature condition was determined by wall temperature measured in a mock-up test. Strain-controlled fatigue tests were conducted using smooth cylindrical specimens made of stainless steel. The fatigue damage at failure of the specimen was calculated using Miner’s rule. The calculated fatigue damage around the hot spot became less than unity and the minimum value was 0.18. Therefore, Miner’s rule predicted non-conservative fatigue life. In addition, the calculated fatigue damage inside the hot spot was larger than those outside the hot spot and at the position of maximum stress fluctuation. Fatigue tests using strain with periodic overload were also conducted in order to investigate the effect of the loading history on fatigue life. It was shown that the strain with periodic overload reduced the fatigue life. The calculated fatigue damage for the strain at the maximum position of stress fluctuation range seemed to be smaller than those at other positions. This implies that the fatigue life can be estimated conservatively from the viewpoint of the loading sequence effect by calculating the fatigue damage using Miner’s rule for the strain at the maximum position of stress fluctuation range.

Palmgren–Miner’s rule and fracture mechanics-based inspection planning

2011 ◽  
Vol 78 (18) ◽  
pp. 3166-3182 ◽  
Author(s):  
Nian-Zhong Chen ◽  
Ge Wang ◽  
C. Guedes Soares
Keyword(s):  
Fracture Mechanics ◽  
Inspection Planning ◽  
Miner’S Rule ◽  
Miner's Rule
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