LCF Life Prediction Model of Coiled Tubing Based on Fatigue Damage Accumulation

2013 ◽  
Vol 699 ◽  
pp. 426-431
Author(s):  
Zong Yue Bi ◽  
Lin Yun Xian
Keyword(s):  
Fatigue Behavior ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Coiled Tubing ◽  
Fatigue Damage Accumulation ◽  
Theoretical Predictions ◽  
Plastic Strain Energy ◽  
Cyclic Plastic Strain ◽  
Damage Rule ◽  
Life Prediction Model

This paper establishes a model to predict the fatigue behavior of coiled tubing subjected to variable total strain conditions. The approach based on nonlinear fatigue cumulative damage rule of effective hysteresis energy dissipation, but requires additional experimental results from fatigue tests that were performed under constant strain amplitude. Cyclic plastic strain energy is measured curve area of cyclic stress-strain curves. it is proved to be quite consistent between theoretical predictions and experimentl datas.

Cross Property Correlations for Metals Subjected to Fatigue Damage Accumulation

2002 ◽  
Author(s):  
Mahesh C. Bogarapu ◽  
Igor Sevostianov
Keyword(s):  
Electrical Resistance ◽  
Damage Accumulation ◽  
Fatigue Tests ◽  
Electric Resistance ◽  
Metal Structures ◽  
Accumulated Damage ◽  
Fatigue Damage Accumulation ◽  
Theoretical Predictions ◽  
Method Of Evaluation ◽  
Better Than

A new method of evaluation of elastic property deterioration due to accumulated damage is suggested and experimentally verified. It is based on the explicit correlations between two groups of anisotropic properties – conductivity and elasticity, recently established for porous/microcracked materials with anisotropic microstructures. An experimental study of fatigue has been done to verify the theoretical predictions. The electrical resistance and Young’s modulus are measured as functions of the number of loading cycles in the standard fatigue tests. The agreement between the theoretical predictions and the direct experimental data is better than 10% in all cases. The results allow one to use the measurement of electric resistance to estimate the damage accumulated in metal structures and decrease in the elastic modulus.

Investigation Into Cumulative Damage Rules to Predict Fretting Fatigue Life of Ti-6Al-4V Under Two-Level Block Loading Condition1

2003 ◽  
Vol 125 (3) ◽  
pp. 315-323 ◽  
Author(s):  
O. Jin ◽  
H. Lee ◽  
S. Mall
Keyword(s):  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Cumulative Damage ◽  
Order Effects ◽  
Block Loading ◽  
Crack Growth Rates ◽  
Damage Rule ◽  
Repeated Block

The effects of variable amplitude loading on fretting fatigue behavior of titanium alloy, Ti-6Al-4V were examined. Fretting fatigue tests were carried out under constant stress amplitude and three different two-level block loading conditions: high-low (Hi-Lo), low-high (Lo-Hi), and repeated block of high and low stress amplitudes. The damage fractions and fretting fatigue lives were estimated by linear and non-linear cumulative damage rules. Damage curve analysis (DCA) and double linear damage rule (DLDR) were capable to account for the loading order effects in Hi-Lo and Lo-Hi loadings. In addition, the predictions by DCA and DLDR were better than that by linear damage rule (LDR). Besides its simplicity of implementation, LDR was also capable of estimating failure lives reasonably well. Repeated two-level block loading resulted in shorter lives and lower fretting fatigue limit compared to those under constant amplitude loading. The degree of reduction in fretting fatigue lives and fatigue strength depended on the ratio of cycles at lower stress amplitude to that at higher stress amplitude. Fracture surface of specimens subjected to Hi-Lo and repeated block loading showed the clear evidence of change in stress amplitude of applied load. Especially, the repeated two-level block loading resulted in characteristic markers which reflected change in crack growth rates corresponding to different stress amplitudes.

Cyclic and Fatigue Behavior of the P355NL1 Steel Under Block Loading

2007 ◽  
Author(s):  
He´lder F. S. G. Pereira ◽  
Abi´lio M. P. De Jesus ◽  
Anto´nio A. Fernandes ◽  
Alfredo S. Ribeiro
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Cumulative Damage ◽  
Sequential Effects ◽  
Block Loading ◽  
Fatigue Damage Accumulation ◽  
Life Predictions

Current fatigue analyses of metallic structures undergoing variable amplitude loading, including pressure vessels, are mostly based on linear cumulative damage concepts, as proposed by Palmgren and Miner. This type of analysis neglects any sequential effects of the loading history. Several studies have shown that linear cumulative damage theories can produce inconsistent fatigue life predictions. In this paper, both fatigue damage accumulation and cyclic elastoplastic behaviors of the P355NL1 steel are characterized, using block loading fatigue tests. The loading is composed by blocks of constant strain-controlled amplitudes, applied according to two and multiple alternate blocks sequences. Also, loading composed by blocks of variable strain-controlled amplitudes are investigated. The block loading illustrates that fatigue damage evolves nonlinearly with the number of load cycles, as a function of the block strain amplitudes. These observations suggest a nonlinear damage accumulation rule with load sequential effects for the P355NL1 steel. However, the damage accumulation nonlinearity and load sequential effects are more evident for the two block loading rather than for multiple alternate block sequences, which suggests that the linear Palmgren-Miner’s rule tend to produce better results for more irregular loading histories. Some phenomenological interpretations for the observed trends are discussed under a fracture mechanics framework.

A Statistically Based Investigation of the Environmental and Cyclic Stress Effects on Fretting Fatigue

1981 ◽  
Vol 103 (3) ◽  
pp. 218-222 ◽  
Author(s):  
C. J. Poon ◽  
D. W. Hoeppner
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Stress Effects ◽  
Mechanics Concepts ◽  
Fractographic Features ◽  
Fretting Damage ◽  
Significant Factors

A completely randomized factorial experiment was conducted to investigate the environmental and cyclic stress effects on the fretting fatigue behavior of 7075-T6 aluminum alloy. Fretting fatigue tests were conducted in vacuum (10−5 Torr) and in laboratory air environment at two maximum cyclic stress levels. The fractographic features of the wear surface with respect to different environments were examined. The experimental results and statistical analysis showed that the environment, cyclic stress, and their interactions were significant factors in reducing the life of 7075-T6 aluminum alloy under fretting conditions. The fractographic analysis showed that fretting damage led to the development of cracks in the fretting areas in both environments. However, the mechanisms involved in crack development were different. The reduction in fatigue life under fretting condition was explained by a model utilizing fracture mechanics concepts.

Failure Analysis of Large-Diameter Coiled Tubing Based on Diameter Growth

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Le Zhao ◽  
Hong Zhang ◽  
Qingquan Duan ◽  
Guoping Tang
Keyword(s):  
Internal Pressure ◽  
Wall Thickness ◽  
High Pressures ◽  
Fatigue Behavior ◽  
Large Diameter ◽  
Fatigue Tests ◽  
Diameter Growth ◽  
Finite Element Software ◽  
Coiled Tubing ◽  
Bending Radius

Abstract Fatigue tests were conducted to analyze the fatigue behavior and diameter growth of large-diameter coiled tubing (CT) under the combined loads of bending and internal pressure. The experimental results reveal that mechanical limitations on the allowable diameter growth mean that the effective working life of CT at high pressures is only a fraction of the available fatigue life. The finite element software abaqus is used to further research the changes in diameter growth and to analyze the sensitivity of CT diameter growth to the main influencing factors, including internal pressure, tubing outside diameter (OD), wall thickness, yield strength, and bending radius. For CT with a diameter larger than 2 in., the diameter growth is sensitive to the above factors. As the bending and straightening cycles increase, the OD of the CT increases in association with obvious ovalization deformation, and the increase in the OD is closely related to the internal pressure load. The redistribution of material causes the wall thickness of the CT to become universally thinner. The ovality of the CT and the uneven decrease in wall thickness reduce the resistance to external extrusion. Therefore, it is becoming increasingly necessary to account for diameter growth as one of the key elements when predicting CT life or determining when to retire a string from service.

Cyclic and Fatigue Behavior of the P355NL1 Steel Under Block Loading

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Hélder F. S. G. Pereira ◽  
Abílio M. P. De Jesus ◽  
Alfredo S. Ribeiro ◽  
António A. Fernandes
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Cumulative Damage ◽  
Sequential Effects ◽  
Block Loading ◽  
Fatigue Damage Accumulation ◽  
Life Predictions

Current fatigue analyses of metallic structures undergoing variable amplitude loading, including pressure vessels, are mostly based on linear cumulative damage concepts, as proposed by Palmgren and Miner. This type of analysis neglects any sequential effects of the loading history. Several studies have shown that linear cumulative damage theories can produce inconsistent fatigue life predictions. In this paper, both fatigue damage accumulation and cyclic elastoplastic behaviors of the P355NL1 steel are characterized using block loading fatigue tests. The loading is composed of blocks of constant strain-controlled amplitudes, applied according to two and multiple alternate blocks sequences. Also, loading composed by blocks of variable strain-controlled amplitudes are investigated. The block loading illustrates that fatigue damage evolves nonlinearly with the number of load cycles, as a function of the block strain amplitudes. These observations suggest a nonlinear damage accumulation rule with load sequential effects for the P355NL1 steel. However, the damage accumulation nonlinearity and load sequential effects are more evident for the two block loading rather than for multiple alternate block sequences, which suggests that the linear Palmgren–Miner rule tends to produce better results for more irregular loading histories. Some phenomenological interpretations for the observed trends are discussed under a fracture mechanics framework.

Fatigue properties by “self-heating” method: Application to orthodontic Ni-Ti wires after hydrogen charging

2018 ◽  
Vol 29 (16) ◽  
pp. 3242-3253 ◽  
Author(s):  
Maha Rokbani ◽  
Luc Saint-Sulpice ◽  
Shabnam Arbab Chirani ◽  
Tarak Bouraoui
Keyword(s):  
Cyclic Loading ◽  
Fatigue Behavior ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Orthodontic Wires ◽  
Heating Method ◽  
Hydrogen Charging ◽  
Self Heating ◽  
Number Of Cycles

Ni-Ti superelastic alloys have been successfully used in orthodontic clinics thanks to their good biomechanical and biochemical behavior. However, during treatment, some orthodontic wires may break in the oral cavity. The susceptibility of these alloys to cyclic loadings and to hydrogen embrittlement is supposed to be main causes of these unexpected failures. This study presents a contribution to studying the effect of hydrogen, obtained after cathodically charging in 0.9% NaCl solution, on the fatigue behavior of Ni-Ti commercial orthodontic wires subjected to high-cycle fatigue. Fatigue tests were analyzed using self-heating method based on observing thermal effects under mechanical cyclic loading. The results obtained with self-heating approach imply that the increase in hydrogen charging time is connected with an increase in the mean stabilized temperature and a decrease in the fatigue life. Self-heating method allows a rapid prediction of the endurance limit with a good reproducibility of fatigue tests at high number of cycles. Furthermore, cyclic stress–induced transformations and conventional fatigue tests under strain control are considered in this work to investigate the effect of hydrogen on cyclic loading type and to acquire for a better understanding of the interaction between hydrogen and thermo-mechanical mechanisms in Ni-Ti alloys.

Metallographic Characterization and Fatigue Damage Initiation in Ti6Al4V Alloy Produced by Direct Metal Laser Sintering

2017 ◽  
Vol 891 ◽  
pp. 311-316 ◽  
Author(s):  
Radomila Konečná ◽  
Gianni Nicoletto ◽  
Adrián Bača ◽  
Ludvík Kunz
Keyword(s):  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Structural Heterogeneity ◽  
Cyclic Stress ◽  
Laser Sintering ◽  
Fatigue Tests ◽  
Ti6al4v Alloy ◽  
Direct Metal Laser Sintering ◽  
Damage Initiation ◽  
Complex Process

Direct Metal Laser Sintering (DMLS) is a complex process where a part is build-up by localized melting of gas atomized powder layers by a concentrated laser beam followed rapid solidification. The microstructure of DMLS produced material is substantially different from that of conventionally manufactured materials, although the ultimate strength is similar. However, yield strength and elongation and especially fatigue behavior may vary considerably according to the process parameters and post fabrication heat treatment because they affect structural heterogeneity, porosity content, residual stresses, and surface conditions. Fatigue tests of DMLS Ti6Al4V alloy are interpreted in the light of a thorough metallographic and fractographic investigation. The fatigue crack initiation for three different cyclic stress directions with respect to build direction is determined by fractography.

scholarly journals Microstructure and Low-Cycle Fatigue Behavior of Al-9Si-4Cu-0.4Mg-0.3Sc Alloy with Different Casting States

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 638 ◽  
Author(s):  
Guanyi Wang ◽  
Xin Che ◽  
Zhipeng Zhang ◽  
Haoyu Zhang ◽  
Siqian Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Cyclic Deformation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Metal Mold ◽  
Die Cast

The low-cycle fatigue behavior of Al-9Si-4Cu-0.4Mg-0.3Sc alloy with different casting states was investigated by performing low-cycle fatigue tests and by means of observations and analysis with a scanning electron microscope (SEM) and a transmission electron microscope (TEM). It was found that the metal-mold cast and die-cast Al-9Si-4Cu-0.4Mg-0.3Sc alloys exhibited the cyclic stress response of strain hardening under all imposed total strain amplitudes. The cyclic deformation resistance and fatigue life of the metal-mold cast Al-9Si-4Cu-0.4Mg-0.3Sc alloy were lower than those of the die-cast Al-9Si-4Cu-0.4Mg-0.3Sc alloy. The plastic strain and elastic strain amplitudes of the metal-mold cast and die-cast Al-9Si-4Cu-0.4Mg-0.3Sc alloys were linearly related to the number of reversals to failure, which obeyed the Coffin-Manson and Basquin formulas, respectively. The results of TEM observation revealed that at all imposed total strain amplitudes, the cyclic deformation mechanisms of the metal-mold cast and die-cast Al-9Si-4Cu-0.4Mg-0.3Sc alloys were planar slip and wavy slip at the lower and higher strain amplitudes, respectively.

Fatigue Behavior of Nuclear Materials Under Air and Environmental Conditions

2013 ◽  
Author(s):  
Karl-Heinz Herter ◽  
Xaver Schuler ◽  
Thomas Weissenberg
Keyword(s):  
Thermal Loading ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Austenitic Stainless Steels ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Crack Growth Behavior ◽  
Low Alloy Steels ◽  
Cycle Fatigue ◽  
Alloy Steels

The assessment of fatigue and cyclic crack growth behavior of safety relevant components is of importance for ageing management with regard to safety and reliability. For cyclic stress evaluation different codes and standards provide fatigue analysis procedures to be performed considering the various mechanical and thermal loading histories and geometric complexities of the components. For the fatigue design curves used as limiting criteria the influence of different factors like e.g. environment, surface finish and temperature must be taken into consideration in an appropriate way. Fatigue tests were performed in the low cycle fatigue and high cycle fatigue regime with low-alloy steels as well as with Nb- and Ti-stabilized German austenitic stainless steels in an air and high temperature BWR environment to extend the state of knowledge of environmentally assisted fatigue as it can occur in BWR plants. Using the RPV steel 22NiMoCr3-7 experimental data was developed to verify the influence of BWR coolant environment (high purity water as well as water containing sulphate with 90 ppb SO4 and water containing chloride with 50 ppb Cl at a test temperature of 240 °C and an oxygen content of 400 ppb) on the fatigue life and to extend the basis for a reliable estimation of the remaining service life of reactor components. Corresponding experiments in air were performed to establish reference data to determine the environmental correction factor Fen. The experimental results are compared with available international mean data curves, the new design curves and on the basis of the environmental factor Fen.

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