Fatigue Life of Ni-Based Single Crystal Super-Alloy Specimen with Single Hole

2021 ◽  
Vol 891 ◽  
pp. 10-16
Author(s):  
Xiang Zhen Xue ◽  
Zhi Xun Wen ◽  
Wen Xian Li
Keyword(s):  
Fatigue Life ◽  
Single Crystal ◽  
Stress Ratio ◽  
Test Results ◽  
Alloy Specimen ◽  
Paris Law ◽  
Single Hole ◽  
Alloy Material ◽  
Life Model ◽  
Super Alloy

A method of predicting the fatigue life under multiaxis loads based on the Paris law and EIFS was proposed. And the fatigue life under different loading stress and stress ratio were investigated. The results show that when the loading stress increased from 450~800 MPa, the fatigue life decreased from 6762379 to 10056, as well as when the stress ratio increased from 0.1~1, the fatigue life increased from 6762379 to 14932368. It was validated by test eventually. And the fatigue life model presented here agrees well with test results. It is significant to the prediction of turbine of Ni-based single crystal super-alloy material with filming hole.

Investigation on Stress and Strain of Ni-Based Single Crystal Super-Alloy Specimen with Single Hole Based on Abacus

2021 ◽  
Vol 891 ◽  
pp. 17-22
Author(s):  
Xiang Zhen Xue ◽  
Zhi Xun Wen ◽  
Wen Xian Li
Keyword(s):  
Fatigue Life ◽  
Single Crystal ◽  
High Reliability ◽  
Turbine Blades ◽  
High Strength ◽  
Initial Crack ◽  
Alloy Specimen ◽  
Single Hole ◽  
Stress Ratios ◽  
Super Alloy

The Miss stress, Max.principal strain and Magnitude displacement have important influence on the fatigue life of the Ni-based single crystal super-alloy turbine blades. This work investigated The Miss stress, Max.principal strain and Magnitude displacement of Ni-based single crystal super-alloy specimen with single hole along dangerous path under different working conditions by Abacus. The results show that the initial crack length and loading stresses are larger, the crack growth on the specimen is faster, and then, the fatigue life is the shorter. Moreover, for the different stress ratios, smaller stress ratio can lead to lower fatigue life. The result is significant to design turbine of Ni-based single crystal super-alloy of high accuracy, high reliability and high strength.

scholarly journals Fatigue Life Prediction of Rolling Bearings Based on Modified SWT Mean Stress Correction

2020 ◽  
Author(s):  
Aodi Yu ◽  
Hong-Zhong Huang ◽  
Yan-Feng Li ◽  
He Li ◽  
Ying Zeng
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Stress Ratio ◽  
Prediction Models ◽  
Great Influence ◽  
Sensitivity Coefficient ◽  
Model Verification ◽  
Mean Stress ◽  
Test Results ◽  
Rolling Bearings

Abstract Mean stress has a great influence on fatigue life, commonly used stress-based life prediction models can only fit the test results of fatigue life under specific stress ratio or mean stress but cannot describe the effect of stress ratio or mean stress on fatigue life. Smith, Watson and Topper (SWT) proposed a simple mean stress correction criterion. However, the SWT model regards the sensitivity coefficient of all materials to mean stress as 0.5, which will lead to inaccurate predictions for materials with a sensitivity coefficient not equal to 0.5. In this paper, considering the sensitivity of different materials to mean stresses, compensation factor is introduced to modify the SWT model, and several sets of experimental data are used for model verification. Then, the proposed model is applied to fatigue life predictions of rolling bearings, and the results of proposed method are compared with test results to verify its accuracy.

A Study on Improvement of Fatigue Life for Woven Glass Fabric/Epoxy Laminate Composite Applied to Railway Vehicle

2010 ◽  
Vol 654-656 ◽  
pp. 2583-2586
Author(s):  
Hee Young Ko ◽  
Kwang Bok Shin ◽  
Jung Seok Kim
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Stress Ratio ◽  
Laminate Composite ◽  
Glass Fabric ◽  
Railway Vehicle ◽  
Test Results ◽  
Laminate Composites ◽  
Remarkable Improvement ◽  
Fatigue Characteristics

In this study, the fatigue characteristics and life of woven glass fabric/epoxy laminate composites applied to railway vehicle were evaluated. The fatigue test was conducted by tension-tension load with stress ratio R of 0.1 and frequency of 5Hz. The material used to fatigue test was two types of woven glass fabric/epoxy laminate composite with and without the reinforcement of carbon/epoxy ply. Also, the fatigue life of woven glass fabric/epoxy laminate composite was compared with that of aluminum 6005 used to the car-body and under-frame structures of railway vehicle. The test results showed that the failure strength and life of woven glass fabric/epoxy laminate composite with the reinforcement of three carbon/epoxy plies had a remarkable improvement in comparison with that of bare specimen without reinforcement.

A Low Cycle Fatigue Life Prediction Model of Single Crystal Nickel-Based Superalloys Using Critical Plane Approach Combined With Crystallographic Slip Theory

2017 ◽  
Author(s):  
Lijuan Mu ◽  
Xuezhi Dong ◽  
Qing Gao ◽  
Yongsheng Tian ◽  
Chunqing Tan
Keyword(s):  
Fatigue Life ◽  
Single Crystal ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Complex Stress State ◽  
Critical Plane ◽  
Crystallographic Slip ◽  
Critical Plane Approach ◽  
Life Model

The anisotropy is the most remarkable characteristic for single crystal nickel-based superalloys, which makes fatigue behavior and life prediction highly correlate with the crystallographic orientation. Based on critical plane approach and preferred crystallographic slip mechanism, an anisotropic LCF life model is proposed to account for orientation-dependent fatigue life in this paper. In addition, the effects of the mean stress and stress-weakening caused by asymmetric loading are also considered. The critical plane is determined by searching for 30 potential slip systems. Moreover, the slip plane with the maximum resolved shear stress amplitude in the crystallographic microstructure of the single crystal nickel-based superalloy is chosen as the critical plane. The LCF test data are utilized to obtain the regression equation by multiple linear fitting method. The presented LCF life model is applicable for more complex stress state and has higher prediction accuracy than the CDY model.

Fatigue Life Calculation of the in-Service Dented Pipeline

2011 ◽  
Vol 467-469 ◽  
pp. 1327-1332 ◽  
Author(s):  
Wu Ying ◽  
Peng Zhang ◽  
Wu Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Life ◽  
Pressure Variation ◽  
Finite Element Models ◽  
Test Results ◽  
Peak Period ◽  
Factors Affecting ◽  
Life Model ◽  
Calculation Results

Dent is one of the important factors affecting pipeline fatigue life, and it will greatly reduce the fatigue life of the pipeline in service. Based on a large number of foreign dented pipeline fatigue test results and fatigue life model, for the typical dent defect, using finite element method, various parameters are changed and finite element models are obtained under different conditions. According to many calculation results, a key ratio of peak period stress and pipeline pressure variation are obtained, which are substituted to the fatigue life model and the example are calculated.

A Fatigue-Life Model of a Rubber Bushing

1980 ◽  
Vol 53 (5) ◽  
pp. 1226-1238 ◽  
Author(s):  
H. L. Oh
Keyword(s):  
Fatigue Life ◽  
Energy Balance ◽  
Design Procedure ◽  
Test Results ◽  
Performance Requirement ◽  
Life Model ◽  
Rubber Bushing

Abstract A major performance requirement for a rubber bushing is durability. The model for fatigue life of a bushing given in Equation (4) was derived using an energy balance concept (energy available versus energy required to extend a tear). This model agreed well with test results. A design procedure was developed from the model which gives the optimum insert geometry for maximum bushing life.

Paris Fatigue Life Modeling of Pressure Vessel Service Simulation Tests

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
John H. Underwood ◽  
John J. Keating ◽  
Edward Troiano ◽  
Gregory N. Vigilante
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Pressure Vessel ◽  
Base Alloy ◽  
Pressure Vessels ◽  
Full Scale ◽  
Test Results ◽  
X Ray Diffraction ◽  
Life Model ◽  
Nickel Base

Results from four groups of full-scale pressure vessel service simulation tests are described and analyzed using Paris fatigue life modeling. The objective is to determine how the vessel and initial crack configurations and applied and residual stresses control the as-tested fatigue life of the vessel. The tube inner radii are in the 40–80 mm range; wall thickness varies from 6 to 80 mm; materials are ASTM A723 pressure vessel steel and IN718 nickel-base alloy; applied internal pressure varies from 90 to 700 MPa. The Paris constant, C, and exponent, m, that describe the fatigue crack propagation rate versus stress intensity factor range for the various vessel materials, were measured as part of the investigation. Extensive, previously published fatigue life results from baseline A723 pressure vessels with well characterized autofrettage residual stresses and C and m values are used to demonstrate that a Paris fatigue life model gives a good description of the measured life. The same model is then used to determine the variables with predominant control over life in three types of pressure vessel for which less information and tests results are available. A design life for pressure vessels is calculated for a specified very low probability of fatigue failure using the log(N)-normal distribution statistics often used for fatigue of structures. The results of the work showed: (i) X-ray diffraction measurements of through-wall autofrettage residual stresses are in excellent agreement with prior neutron diffraction measurements from a baseline autofrettaged A723 pressure vessel; these verified autofrettage residual stresses then provide critical input to the baseline Paris life modeling; (ii) comparison of the various full-scale fatigue test results with results from the Paris fatigue life model shows close agreement when autofrettage residual stresses are incorporated into models; (iii) model results for A723 steel vessels with yield strength reduced from the initial 1400 MPa value and degree of autofrettage increased from the initial 40% value indicates a significantly improved resistance to brittle failure with no loss of fatigue life; (iv] comparison of model fatigue life results for IN718 nickel-base alloy vessels with their full-scale test results is improved when near-bore residual stresses measured by X-ray diffraction are included in the model calculations.

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