Predicting the multiaxial fatigue limit and the multiaxial high-cycle fatigue life based on the unified equivalent shear stress from axial strength characteristics with various waveforms

2018 ◽  
Vol 112 ◽  
pp. 52-62 ◽  
Author(s):  
Go Matsubara ◽  
Atsushi Hayashida ◽  
Daichi Kano
Keyword(s):  
Shear Stress ◽  
Fatigue Life ◽  
Fatigue Limit ◽  
High Cycle Fatigue ◽  
Multiaxial Fatigue ◽  
Strength Characteristics ◽  
Cycle Fatigue ◽  
Axial Strength

Fatigue Performance of Low Rigidity Titanium Alloy for Biomedical Applications

2004 ◽  
Vol 449-452 ◽  
pp. 1265-1268
Author(s):  
Toshikazu Akahori ◽  
Mitsuo Niinomi ◽  
Hisao Fukui ◽  
Akihiro Suzuki
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Tangential Force ◽  
Solution Treatment ◽  
Beta Phase ◽  
Fretting Fatigue ◽  
Cycle Fatigue

Microstructures of Ti-29Nb-13Ta-4.6Zr (TNTZ) aged at temperatures between 573 and 723 K after solution treatment at 1063 K have super fine omega phase, or􀀂 both super fine alpha and omega phases, respectively in beta phase with an average grain diameter of 20 µm. Plain fatigue strength of TNTZ aged after solution treatment is much greater than that of as-solutionized TNTZ in both low cycle fatigue and high cycle fatigue life regions. This is due to the improvement of the balance of strength and ductility by the precipitation of alpha phase. Fretting fatigue strength of TNTZ conducted with various heat treatments decreases dramatically as compared with their plain fatigue strength in both low cycle fatigue and high cycle fatigue life regions. In this case, the decreasing ratio of fretting fatigue life increases with increasing the small crack propagation area where both the tangential force and frictional force at the contact plane of pad exist. In fretting fatigue in air, the ratio of fretting damage (Pf/Ff), where Pf and Ff stand for plain fatigue limit and fretting fatigue limit, respectively, increases with increasing elastic modulus. In fretting fatigue in Ringer’s solution, the passive film on specimen surface is broken by fretting action in TNTZ, which have excellent corrosion resistance, and, as a result, corrosion pits that lead to decreasing fretting fatigue strength especially in high cycle fatigue life region, are formed on its surface.

Fretting High-Cycle Fatigue Assessment through a Multiaxial Critical Plane-Based Criterion in Conjunction with the Taylor’s Point Method

2016 ◽  
Vol 258 ◽  
pp. 217-220 ◽  
Author(s):  
Camilla Ronchei ◽  
Andrea Carpinteri ◽  
Giovanni Fortese ◽  
Daniela Scorza ◽  
Sabrina Vantadori
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Multiaxial Fatigue ◽  
Point Method ◽  
Cycle Fatigue ◽  
Structural Components ◽  
Severe Stress ◽  
Critical Plane ◽  
The Common ◽  
Crack Initiation Life

The critical plane-based multiaxial criterion originally proposed by the authors for plain fatigue is here applied to estimate the crack initiation life of fretting high-cycle fatigued structural components. Although fretting fatigue can be regarded as a case of multiaxial fatigue, the common multiaxial fatigue criteria have to be modified to account for the severe stress gradients in the contact zone. Therefore, the above criterion is used in conjunction with the Taylor’s point method to numerically estimate the fatigue life of Ti-6Al-4V and Al-4Cu specimens under cylindrical contacts.

scholarly journals The Effect of Baking Heat Treatment on the Fatigue Strength and Life of Shot Peened 4340M Landing Gear Steel

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5711
Author(s):  
Seok-Hwan Ahn ◽  
Jongman Heo ◽  
Jungsik Kim ◽  
Hyeongseob Hwang ◽  
In-Sik Cho
Keyword(s):  
Heat Treatment ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Shot Peening ◽  
High Cycle Fatigue ◽  
Landing Gear ◽  
Cycle Fatigue ◽  
Heat Treated ◽  
Ultrasonic Fatigue

In this study, the effect of baking heat treatment on fatigue strength and fatigue life was evaluated by performing baking heat treatment after shot peening treatment on 4340M steel for landing gear. An ultrasonic fatigue test was performed to obtain the S–N curve, and the fatigue strength and fatigue life were compared. The micro hardness of shot peening showed a maximum at a hardened depth of about 50 μm and was almost uniform when it arrived at the hardened depth of about 400 μm. The overall average tensile strength after the baking heat treatment was lowered by about 80–111 MPa, but the yield strength was improved by about 206–262 MPa. The five cases of specimens showed similar fatigue strength and fatigue life in high cycle fatigue (HCF) regime. However, the fatigue limit of the baking heat treated specimens showed an increasing tendency rather than that of shot peening specimens when the fatigue life was extended to the very high cycle fatigue (VHCF) regime. The effect of baking heat treatment was identified from improved fatigue limit when baking heat was used to treat the specimen treated by shot peening containing inclusions. The optimum temperature range for the better baking heat treatment effect could be constrained not to exceed maximum 246 °C.

The Influence of Multiaxial Superimposed Static Mean Stress on High-Cycle Fatigue Life of Cu-ETP Copper

2016 ◽  
Vol 250 ◽  
pp. 157-162
Author(s):  
Lukasz Pejkowski ◽  
Dariusz Skibicki ◽  
Mateusz Wirwicki
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Mean Stress ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Proportional Loading ◽  
Mean Stresses

High–cycle multiaxial fatigue tests under proportional and non-proportional loading conditions with various combinations of superimposed static mean stresses was carried out on Cu-ETP copper. The results show differences in fatigue life between various ratios of mean stresses. These results are similar to others described in the literature.

Multiaxial high-cycle fatigue life prediction model based on the critical plane approach considering mean stress effects

2016 ◽  
Vol 27 (1) ◽  
pp. 32-46 ◽  
Author(s):  
Jia-Liang Zhang ◽  
De-Guang Shang ◽  
Yu-Juan Sun ◽  
Xiao-Wei Wang
Keyword(s):  
Shear Stress ◽  
Normal Stress ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Multiaxial Fatigue ◽  
Cycle Fatigue ◽  
Critical Plane ◽  
Stress Effects ◽  
Critical Plane Approach ◽  
Fatigue Criterion

The aim of this paper is to propose a modified multiaxial high-cycle fatigue criterion based on the critical plane approach. The proposed criterion contains three parameters, that is, shear stress amplitude, normal stress amplitude and mean normal stress. In order to take into account the mean shear stress effects, the critical plane is determined by the maximum shear stress. In the proposed multiaxial fatigue criterion, the influence of mean normal stress on fatigue damage is also considered. Based on the proposed criterion, the multiaxial fatigue life is predicted, and the results showed a good agreement with experimental data obtained from some literatures.

Development of an Improved High Cycle Fatigue Criterion

2004 ◽  
Author(s):  
Onome Scott-Emuakpor ◽  
M.-H. Herman Shen ◽  
Charles Cross ◽  
Jeffrey Calcaterra ◽  
Tommy George
Keyword(s):  
Fatigue Life ◽  
Fatigue Limit ◽  
Life Prediction ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Low Cost ◽  
Testing Procedure ◽  
Cycle Fatigue ◽  
Bending Fatigue ◽  
Fatigue Criterion

An integrated computational-experimental approach for prediction of total fatigue life applied to uniaxial stress state is developed. The approach consists of the following elements: (1) development of a vibration based fatigue testing procedure to achieve low cost bending fatigue experiments and (2) development of a life prediction and estimation implementation scheme for calculating effective fatigue cycles. A series of fully reversed bending fatigue tests were carried out using a vibration-based testing procedure to investigate the effects of bending stress on fatigue limit. The results indicate that the fatigue limit for 6061-T6 aluminum is approximately 20% higher than the respective limit in fully reversed tension-compression (axial). To validate the experimental observations and further evaluate the possibility of prediction of fatigue life, an improved high cycle fatigue criterion has been developed, which allows one to systematically determine the fatigue life based on the amount of energy loss per fatigue cycle. A comparison between the prediction and the experimental results was conducted and shows that the criterion is capable of providing accurate fatigue life prediction.

High cycle fatigue property and fracture behavior of high-strength austempered ductile iron

2015 ◽  
Vol 231 (4) ◽  
pp. 423-429
Author(s):  
Qingpeng Song ◽  
Jiwang Zhang ◽  
Ning Zhang ◽  
Wei Li ◽  
Liantao Lu
Keyword(s):  
Fatigue Life ◽  
Fatigue Limit ◽  
Ductile Iron ◽  
High Cycle Fatigue ◽  
Extreme Values ◽  
Fatigue Property ◽  
High Strength ◽  
Defect Size ◽  
Austempered Ductile Iron ◽  
Cycle Fatigue

The high cycle fatigue tests of high-strength austempered ductile iron of grade 1200/850/04 (ASTM 897 M-06) were conducted by the high frequency fatigue machine. The results show that the S–N curve decreases continuously and there is no conventional fatigue limit at 107 cycles. According to the fracture surface observations, at short fatigue life region the specimens fail from defects at specimen surface and at long fatigue life region the specimens fail from internal defects with fish-eye area around it. According to the defect sizes measured in the standard inspection areas of the material, the maximum defect size evaluated by the statistics of extreme values method is in accordance with that of the fatigue test results. Meanwhile, it is obvious that the fatigue strength of austempered ductile iron is influenced by the original defect size and the fatigue limit can be well evaluated by the Murakami equation.

Multiaxial Fatigue in Drill Pipes Under Non-Proportional Loading

2017 ◽  
Author(s):  
Nahla A. Helmy ◽  
Maher Y. A. Younan
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Drill Pipe ◽  
Real Life ◽  
Design Guidelines ◽  
Multiaxial Fatigue ◽  
Data Sets ◽  
Cycle Fatigue ◽  
Proportional Loading

The scope of this research is to estimate the fatigue life and crack initiation direction in components subjected to multiaxial, nonproportional loading. Two critical plane approaches — Fatemi-Socie and McDiarmid — were used to estimate low cycle and high cycle fatigue lives, respectively. A software program (Elrond) was constructed to estimate the fatigue life and crack initiation plane. The code was validated using experimental fatigue data sets from previous research, then was applied to a real-life drilling problem. Drill pipe operating in the “Build and Hold” drilling job condition was analyzed using the developed software. Results were compared with the API RP7G fatigue design guidelines. Fatigue life charts were prepared using fatigue lives estimated by Elrond at several axial loadings, dogleg severities and torque amplitudes. Also, maximum allowable torque under high cycle fatigue conditions was estimated.

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