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.

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 Multiaxial fatigue behavior of 2618 aluminum alloy

2019 ◽  
Vol 300 ◽  
pp. 09003
Author(s):  
Benaïssa Malek ◽  
Catherine Mabru ◽  
Michel Chaussumier
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Internal Pressure ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Mean Stress ◽  
Research Project ◽  
Pressure Tests

The purpose of the present research project is to study multiaxial fatigue behavior of 2618 alloy. The influence of mean stress on the fatigue behavior under tension and torsion is particularly investigated. Fatigue tests under combined tensile-torsion, in or out of phase, as well as combined tensile-torsion-internal pressure tests have also been conducted. Multiaxial fatigue results are analyzed according to Fatemi-Socie criterion to predict the fatigue life.

scholarly journals The Effect of Laser Peening without Coating on the Fatigue of a 6082-T6 Aluminum Alloy with a Curved Notch

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 728 ◽  
Author(s):  
Enrico Troiani ◽  
Nicola Zavatta
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Fatigue Behavior ◽  
Surface Hardness ◽  
Element Model ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Laser Peening ◽  
Laser Peening Without Coating

Laser shock peening has established itself as an effective surface treatment to enhance the fatigue properties of metallic materials. Although a number of works have dealt with the formation of residual stresses, and their consequent effects on the fatigue behavior, the influence of material geometry on the peening process has not been widely addressed. In this paper, Laser Peening without Coating (LPwC) is applied at the surface of a notch in specimens made of a 6082-T6 aluminum alloy. The treated specimens are tested by three-point bending fatigue tests, and their fatigue life is compared to that of untreated samples with an identical geometry. The fatigue life of the treated specimens is found to be 1.7 to 3.3 times longer. Brinell hardness measurements evidence an increase in the surface hardness of about 50%, following the treatment. The material response to peening is modelled by a finite element model, and the compressive residual stresses are computed accordingly. Stresses as high as −210 MPa are present at the notch. The ratio between the notch curvature and the laser spot radius is proposed as a parameter to evaluate the influence of the notch.

A STUDY ON THE FRETTING FATIGUE LIFE OF ZIRCALOY ALLOYS

2008 ◽  
Vol 22 (11) ◽  
pp. 851-856
Author(s):  
JAE-DO KWON ◽  
DAE-KYU PARK ◽  
SEUNG-WAN WOO ◽  
YOUNG-SUCK CHAI
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Cyclic Damage

Studies on the strength and fatigue life of machines and structures have been conducted in accordance with the development of modern industries. In particular, fine and repetitive cyclic damage occurring in contact regions has been known to have an impact on fretting fatigue fractures. The main component of zircaloy alloy is Zr , and it possesses good mechanical characteristics at high temperatures. This alloy is used in the fuel rod material of nuclear power plants because of its excellent resistance. In this paper, the effect of the fretting damage on the fatigue behavior of the zircaloy alloy is studied. Further, various types of mechanical tests such as tension and plain fatigue tests are performed. Fretting fatigue tests are performed with a flat-flat contact configuration using a bridge-type contact pad and plate-type specimen. Through these experiments, it is found that the fretting fatigue strength decreases by about 80% as compared to the plain fatigue strength. Oblique cracks are observed in the initial stage of the fretting fatigue, in which damaged areas are found. These results can be used as the basic data for the structural integrity evaluation of corrosion-resisting alloys considering the fretting damages.

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.

A STUDY ON FRETTING FATIGUE LIFE IN ELEVATED TEMPERATURE FOR INCOLOY 800

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2561-2566
Author(s):  
JAE DO KWON ◽  
SEUNG WAN WOO ◽  
IL SUP CHUNG ◽  
DONG HWAN YOON ◽  
DAE KYU PARK
Keyword(s):  
Elevated Temperature ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Chromium Alloy ◽  
Nickel Chromium ◽  
Incoloy 800 ◽  
Iron Nickel ◽  
To Receive

Incoloy 800, which is used within steam generator tubes, is a heat resistant material since it is an iron-nickel-chromium alloy. However, construction of a systematic database is needed to receive integrity data defecting insurance of specific data about room and elevated temperature fretting fatigue behavior for Incoloy 800. Accordingly, this study investigates the specific change in fatigue limitations under the condition of the fretting fatigue as compared to that under the condition of the plain fatigue by performing plain and fretting fatigue tests on Incoloy 800 at 320°C, real operating temperature and at room-temperature, respectively. The change in the frictional force is measured during the fretting fatigue testing against the repeated cycle, and the mechanism of fretting fatigue is investigated through the observation of the fatigue-fracture surface.

Effects of Shot-Peening on Fretting-Fatigue Behavior of Ti-6Al-4V

2002 ◽  
Vol 124 (2) ◽  
pp. 222-228 ◽  
Author(s):  
S. A. Namjoshi ◽  
V. K. Jain ◽  
S. Mall
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Contact Region ◽  
Fretting Fatigue ◽  
Initiation Site ◽  
Fatigue Tests ◽  
Residual Tensile Stress ◽  
X Ray Diffraction ◽  
Element Analysis

The effects of shot-peening on the fretting fatigue behavior of titanium alloy, Ti-6Al-4V were investigated. Specimens were shot-peened as per AMS 2432 standard. X-ray diffraction analysis measured a maximum compressive stress of 800 MPa at the specimen surface, which reduced to zero at a depth of 188 μm. The compensatory residual tensile stress in the specimen was estimated using a curve fitting technique, the maximum value of which was found to be 260 MPa at a depth of 255 μm. Fretting fatigue tests were conducted at room temperature at a cyclic frequency of 200 Hz. Scanning electron microscopy of the shot-peened fretting fatigue specimens showed that the crack initiated at a point below the contact surface, the depth of which was in the range of 200–300 μm. Finite element analysis of the fretting fatigue specimens was also conducted. Fatigue life diagrams were established for the fretting fatigue specimens with and without shot-peening, and were compared to those under the plain fatigue condition, i.e. without fretting. Shot-peening improved the fretting fatigue life of Ti-6Al-4V; furthermore, it moved the crack initiation site from the fretting contact region to a region inside the specimen. Moreover, stress analysis showed that the fatigue failure of shot-peened specimens was caused by the compensatory tensile residual stress.

INVESTIGATION OF FRETTING FATIGUE BEHAVIOR OF TI811 ALLOY AT ELEVATED TEMPERATURE

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5489-5494
Author(s):  
XIAO-HUA ZHANG ◽  
DAO-XIN LIU
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Contact Pressure ◽  
Fatigue Failure ◽  
High Frequency ◽  
Driving Force ◽  
Fatigue Behavior ◽  
Failure Process ◽  
Failure Mechanisms ◽  
Fretting Fatigue

The fretting fatigue behavior of the Ti 811titanium alloy, as influenced by temperature, slip amplitude, and contact pressure, was investigated using a high-frequency fatigue machine and a home-made high-temperature apparatus. The fretting fatigue failure mechanisms were studied by observing the fretting surface morphology features. The results show that the sensitivity to fretting fatigue is high at both 350°C and 500°C. The higher the temperature is, the more sensitive the alloy is to fretting fatigue failure. Creep is an important factor that influences the fretting fatigue failure process at elevated temperature. The fretting fatigue life of the Ti 811 alloy does not change in a monotonic way as the slip amplitude and contact pressure increase. This is due to the fact that the slip amplitude affects the action of fatigue and wear in the fretting process, and the nominal contact pressure affects the distribution and concentration of the stress and the amplitude of fretting slip at the contact surface, and thus further influences the crack initiation probability and the driving force for propagation.

Influence of Wear Properties on Fretting Fatigue Life of a CK45 Alloy and the Al7175 Alloy

2008 ◽  
Vol 587-588 ◽  
pp. 971-975 ◽  
Author(s):  
M. Buciumeanu ◽  
A.S. Miranda ◽  
F.S. Silva
Keyword(s):  
Wear Resistance ◽  
Fatigue Life ◽  
Material Properties ◽  
Fatigue Behavior ◽  
Synergetic Effect ◽  
Fretting Fatigue ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Wear Properties

The main objective of this work was to study the influence of the wear properties of two commercial alloys (CK45 and Al7175) on their fretting fatigue behavior. It is verified the effect of material local degradation by wear on a fatigue strength reduction factor, namely the stress concentration factor, and on the overall fretting fatigue life of these materials. The fretting fatigue phenomenon is a synergetic effect between wear and fatigue. It is dependent on both the fatigue and the wear properties of the materials. Material properties promoting an increase in wear resistance should enhance fretting fatigue life.

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