Prediction of Fretting Fatigue Life of Aluminum Alloy LY12CZ

2010 ◽  
Vol 146-147 ◽  
pp. 252-256
Author(s):  
Moo Sheng Yang ◽  
Yue Liang Chen ◽  
Yu Quan Bi ◽  
Wen Hao Jiang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Influence Factor ◽  
Stress Amplitude ◽  
Normal Load ◽  
Fretting Fatigue ◽  
Damage Parameter ◽  
Finite Element Software ◽  
Increase With Increase ◽  
Bulk Stress

Stress in the interface of contacts was calculated applying finite element software/ABAQUS, with which the Ruiz fretting damage parameter was obtained and the location for crack formation was found. A new model for predicting fretting fatigue life has been presented based on friction work. The rationality and effectiveness of the model were validated according to the contrast of experiment life and predicting life. At last influence factor on fretting fatigue life of aerial aluminum alloy LY12CZ was investigated with the model. The results revealed that fretting fatigue life decreased monotonously with the increasing of normal load and then became constant at higher pressures. At low normal load, fretting fatigue life was found to increase with increase in the pad radius. At high normal load, however, the fretting fatigue life remained almost unchanged with changes in the fretting pad radius. The bulk stress amplitude had the dominant effect on fretting fatigue life. The fretting fatigue life diminished as the bulk stress amplitude increased.

Analyses of Contact Pressure and Stress Amplitude Effects on Fretting Fatigue Life

2000 ◽  
Vol 123 (1) ◽  
pp. 85-93 ◽  
Author(s):  
K. Iyer ◽  
S. Mall
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Contact Pressure ◽  
Stress Amplitude ◽  
Normal Load ◽  
Contact Region ◽  
Local Stress ◽  
Fretting Fatigue ◽  
Element Analysis ◽  
Stress Ratios

Elastic-plastic finite element analyses of a cylinder-on-plate configuration, studied experimentally, were performed to provide an explanation for the decrease in fretting fatigue life with increasing contact pressure. Three values of normal load, namely 1338 N, 2230 N, and 3567 N, and three stress ratios (0.1, 0.5, and 0.7) were considered. Based on a previously determined dependency between contact pressure and friction coefficient, the effect of coefficient of friction was also evaluated. The deformation remained elastic under all conditions examined. Cyclic, interfacial stresses, and slips were analyzed in detail. The amplification of remotely applied cyclic stress in the contact region is shown to provide a rationale for the effect of contact pressure and stress amplitude on life. Comparisons with previous experiments indicate that the local stress range computed from finite element analysis may be sufficient for predicting fretting fatigue life. Further, the results suggest that the slip amplitude and shear traction may be neglected for this purpose.

scholarly journals Fretting-Fatigue Analysis of Shot-Peened Al 7075-T651 Test Specimens

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 586 ◽  
Author(s):  
Vicente Martín ◽  
Jesús Vázquez ◽  
Carlos Navarro ◽  
Jaime Domínguez
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Shot Peening ◽  
Normal Load ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Material Surface ◽  
Tangential Load ◽  
Bulk Stress ◽  
Al 7075

Shot peening is a mechanical treatment that induces several changes in the material: surface roughness, increased hardness close to the surface, and, the most important, compressive residual stresses. This paper analyzes the effect of this treatment on alloy Al 7075-T651 in the case of fretting fatigue with cylindrical contact through the results of 114 fretting fatigue tests. There are three independent loads applied in this type of test: a constant normal load N, pressing the contact pad against the specimen; a cyclic bulk stress σ in the specimen; and a cyclic tangential load Q through the contact. Four specimens at each of 23 different combinations of these three parameters were tested—two specimens without any treatment and two treated with shot peening. The fatigue lives, contact surface, fracture surface, and residual stresses and hardness were studied. Improvement in fatigue life ranged from 3 to 22, depending on fatigue life. The relaxation of residual-stress distribution related to the number of applied cycles was also measured. Finally, another group of specimens treated with shot peening was polished and tested, obtaining similar lives as in the tests with specimens that were shot-peened but not polished.

The Effects of Periodic High Loads on Fretting Fatigue

1981 ◽  
Vol 103 (3) ◽  
pp. 223-228 ◽  
Author(s):  
A. Kantimathi ◽  
J. A. Alic
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Growth Retardation ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Constant Amplitude ◽  
Axial Loads ◽  
Prolonged Fatigue ◽  
Stress Ratios ◽  
Crack Growth Retardation

Fretting fatigue tests have been conducted on 7075-T7351 aluminum alloy coupons with fretting pads of the same material. Three different stress ratios were used, the otherwise constant amplitude axial loads being interrupted every 1000 cycles by either tensile overloads to 400 MPa or compressive underloads to −200 MPa. Tensile overloads greatly prolonged fatigue life for low stresses where the overload ratios were 1.6 and above; compressive underloads had comparatively little effect. The results are discussed in terms of crack growth retardation phenomena.

scholarly journals A Fatigue Life Prediction Model Based on Modified Resolved Shear Stress for Nickel-Based Single Crystal Superalloys

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 180 ◽  
Author(s):  
Jialiang Wang ◽  
Dasheng Wei ◽  
Yanrong Wang ◽  
Xianghua Jiang
Keyword(s):  
Shear Stress ◽  
Fatigue Life ◽  
Prediction Model ◽  
Single Crystal ◽  
Life Prediction ◽  
Stress Amplitude ◽  
Damage Parameter ◽  
Fatigue Life Prediction ◽  
Model Based ◽  
Life Prediction Model

In this paper, the viewpoint that maximum resolved shear stress corresponding to the two slip systems in a nickel-based single crystal high-temperature fatigue experiment works together was put forward. A nickel-based single crystal fatigue life prediction model based on modified resolved shear stress amplitude was proposed. For the four groups of fatigue data, eight classical fatigue life prediction models were compared with the model proposed in this paper. Strain parameter is poor in fatigue life prediction as a damage parameter. The life prediction results of the fatigue life prediction model with stress amplitude as the damage parameter, the fatigue life prediction model with maximum resolved shear stress in 30 slip directions as the damage parameter, and the McDiarmid (McD) model, are better. The model proposed in this paper has higher life prediction accuracy.

Relationship Between Fatigue Life Distribution, Notch Configuration, and S-N Curve of a 2024-T4 Aluminum Alloy

1985 ◽  
Vol 107 (3) ◽  
pp. 214-220 ◽  
Author(s):  
T. Shimokawa ◽  
Y. Hamaguchi
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Stress Amplitude ◽  
Fatigue Tests ◽  
Test Results ◽  
Notched Specimens ◽  
Wide Range ◽  
Life Distributions ◽  
The Relationship ◽  
Test Stress

The objective of this study is to identify the most closely related variable to the distribution of fatigue life in unnotched and three kinds of notched 2024-T4 aluminum alloy specimens. Carefully designed fatigue tests under a constant temperature and humidity condition provided fatigue life distributions over a wide range of stress amplitude. This study used about 1000 specimens. On the basis of the test results, the dependence of the scatter in fatigue life on notch configuration, the period to crack initiation, the level of stress amplitude, the median fatigue life, and the slope of the median S-N curve is investigated, and the relationship between the distributional form of fatigue life and the shape of the median S-N curve is discussed. It is concluded that the slope and shape of the median S-N curve in the vicinity of the test stress level are closely related to the scatter and distributional form of fatigue life respectively. This is common to the unnotched and three kinds of notched specimens. A variability hypothesis to correlate the median S-N curve with fatigue life distributions is examined.

Effect of Mean Stress on 2A12-T4 Aluminum Alloy under Tension-Torsion Constant Amplitude Loading

2016 ◽  
Vol 713 ◽  
pp. 334-337
Author(s):  
Tian Qing Liu ◽  
Xin Hong Shi ◽  
Jian Yu Zhang
Keyword(s):  
Shear Stress ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Phase Angle ◽  
Stress Amplitude ◽  
Maximum Shear Stress ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Normal Mean ◽  
Fracture Appearance

Fatigue tests have been carried out to investigate the effects of mean-stress and phase-difference on the tension-torsion fatigue failure of 2A12-T4 aluminum alloy. The results show that for fully reversed tension-torsion loading, the fatigue life increases with the increase of phase angle, but the fatigue life decreases with the increase of phase angle, when mean-stress exists, both for shear mean-stress and normal mean-stress. Fracture appearance shows that the crack initiation is on the direction of maximum shear stress amplitude plane. Critical plane criteria based on the linear combination of the maximum shear stress amplitude and maximum normal stress are studied and further discussion on the drawbacks of this kind of criteria are performed.

Multiaxial Fatigue of 6061-T6 Aluminum Alloy under Corrosive Environment

2016 ◽  
Vol 853 ◽  
pp. 77-82
Author(s):  
Xu Chen ◽  
Rui Si Xing ◽  
Xiao Peng Liu
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Stress Amplitude ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Plastic Strain Amplitude ◽  
Multiaxial Fatigue ◽  
Corrosive Environment

Aluminium alloys are widely used in the fields of automobile, machinery and naval construction. To investigate the effect of non-proportional loadings and corrosive environment on the fatigue resistance of 6061-T6 aluminum alloy, a set of uniaxial and multiaxial low cycle fatigue tests were carried out. Firstly, the results of uniaxial tests showed that the alloy exhibited cyclic hardening then cyclic softening. With the increase of stress amplitude the cyclic softening became pronounced. The increasing of plastic deformation was basically cyclically stable with small plastic strain amplitude accumulation when the stress amplitude was lower than 200MPa ,while it was increasing rapidly when the stress amplitude was higher than 220MPa. Secondly, it was observed that non-proportional cycle additional hardening of 6061-T6 aluminum alloy was little. While the fatigue life was badly affected by the loading paths. Thirdly ,the fatigue corrosion interactions were also talked about in details by performing the tests under the same loading conditions with corrosive environment. The experiment proved that the seawater corrosion has huge impact on fatigue life under pH 3. Finally, a multi-axial fatigue life prediction model was used to predict the fatigue life with or without the corrosive environment which showed a good agreement with experimental data.

The Influence of Humid Environment on Fatigue Property of Pre-Corroded 7XXX Aluminum Alloy

2011 ◽  
Vol 314-316 ◽  
pp. 1406-1410 ◽  
Author(s):  
Li Hui ◽  
Song Zhou ◽  
Liang Xu ◽  
Shao Hua Ma ◽  
Yan Wang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Influence Factor ◽  
High Reliability ◽  
Fatigue Property ◽  
Mean Value ◽  
Humid Environment

The influence of humid environment on fatigue property of pre-corroded 7XXX aluminum alloy were investigated by means of fatigue and staircase experiments (Kt=1 and Kt=3). The results showed that humid environment significantly reduces both fatigue life and strength with the influence-factor of 0.7339(Kt=1), 0.8603(Kt=3) and 0.973(Kt=1), 0.971(Kt=3), respectively. The humid environment enlarges the dispersivity of fatigue life. As a consequence, an unconservative results on prediction of the fatigue life with high reliability of 99.9% will be obtained, based on the corrosion-influence-factor reached from eigenvalue or mean value .

scholarly journals Some aspects of fretting fatigue under cyclic normal loading

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Farshad Abbasi ◽  
G. H. Majzoobi
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Normal Load ◽  
Testing Machine ◽  
Low Frequency ◽  
Load Condition ◽  
Fretting Fatigue ◽  
Normal Loading ◽  
Drastic Effect ◽  
Fretting Damage

Fretting fatigue has been studied mainly under constant normal loading, as it requires simple equipment which can be assembled on a universal fatigue testing machine. Recently, we [1] have introduced an innovative fretting fatigue apparatus in which the contact pressure can independently be varied during the test. In a recent publication [2] we have investigated the effect of normal load frequency on fretting fatigue life of Al7075-T6 under cyclic normal load condition. It was found that the low frequency of normal load has drastic effect on fretting fatigue life. The effect, however, gradually diminishes with the frequency increase and vanishes at the frequency of around 80Hz. In another publication [3] we have compared the results of constant normal loading with those of in phase, 90° and 180° degrees out-of-phase loadings. It was found that the constant normal loading has the least fretting damage, while the maximum fretting damage occurs by in-phase loading. The results also showed that the out-of-phase loading had improving effect on fretting fatigue life with respect to the in-phase condition. Recently, Ciaverella [4] has published a discussion on our publications [2, 3]. He believes that some of our experimental results needs further discussion. Therefore, the objective of this article is to answer three main points he has raised in his article [4]. We hope that this discussion could lead to some progress.

scholarly journals Experimental and numerical investigation into effect of elevated temperature on fretting fatigue behavior

2011 ◽  
Vol 2 (1) ◽  
pp. 2-11
Author(s):  
R. Hojjati Talemi ◽  
M. Soori ◽  
M. Abdel Wahab ◽  
Patrick De Baets
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Elevated Temperature ◽  
Gas Turbines ◽  
Fatigue Behavior ◽  
Surface Oxidation ◽  
Fretting Fatigue ◽  
Growth Increment ◽  
Fatigue Tests ◽  
New Device

t Fretting fatigue damage occurs in contacting parts when they are subjected to fluctuating loadingsand sliding movements at the same time. This phenomenon may occur in many applications such asbearings/ shafts, bolted and riveted connections, steel cables, and steam and gas turbines. In this paper,the effect of elevated temperature on fretting fatigue life of Al7075-T6 is investigated using a new device forfretting fatigue tests with variable crank shaft mechanism. Also a finite element modeling method was usedto estimate crack propagation lifetime in aluminum alloy, Al7075-T6 specimens at elevated temperatureunder fretting condition. In this method, shear and normal stresses that are caused by contact load areupdated at each crack growth increment. Finally, a comparison between the experimental and numericalresults is done in order to evaluate the FE simulation.Department of mechanical engineering, Islamic Azad University, Takestan Branch, Takestan, IranThe experimental results show that: (i) fretting fatigue life of the material increases with temperature up to350°C by 180% for low stresses and decreases by 40% for high stresses, (ii) this fashion of variation offretting fatigue life versus temperature is believed to be due to degradation of material properties whichoccurs by overaging and wear resistance increase due to oxidation of aluminum alloy. While overaginggives rise to degradation of mechanical strength of material and hence the reduction of its fretting fatiguelife, surface oxidation of the specimens brings some improvement of fatigue behavior of the material.Metallurgical examination of the specimens reveals that temperature results in precipitation of impurities ofal-7075-T6. The size of precipitated impurities and their distances gets bigger as temperature increases.This could be a reason for material degradation of specimens which are exposed to heating for longer timeduration.

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