Fretting Fatigue Strength and Life Estimation Considering the Fretting Wear Process

2007 ◽  
pp. 882-885
Author(s):  
Toshio Hattori ◽  
Naoya Nishimura ◽  
Minoru Yamashita
Keyword(s):  
Fatigue Strength ◽  
Fretting Fatigue ◽  
Fretting Wear ◽  
Wear Process ◽  
Life Estimation

Experimental Validation of Fretting Fatigue Strength and Fretting Wear Rate at Contact Surface of Turbine-Blade-Shroud Cover

2012 ◽  
Author(s):  
Kunio Asai ◽  
Takeshi Kudo ◽  
Hideo Yoda
Keyword(s):  
Fatigue Strength ◽  
Wear Rate ◽  
Contact Pressure ◽  
Contact Force ◽  
Contact Surface ◽  
Fretting Fatigue ◽  
Fretting Wear ◽  
Dissipated Energy ◽  
Normal Contact ◽  
Vibratory Load

In continuously coupled blade structures, fretting fatigue and wear have to be considered as supposed failure modes at the contact surface of the shroud cover, which is subject to steady contact pressure from centrifugal force and the vibratory load of the blade. We did unique fretting tests that modeled the structure of the shroud cover, where the vibratory load is only carried by the contact friction force, i.e., a type of friction. What was investigated in this study are fretting fatigue strength, wear rate, and friction characteristics, such as friction coefficient and slip-range of 12%-Cr steel blade material. The friction-type tests showed that fretting fatigue strength decreases with the contact pressure and a critical normal contact force exists under which fretting fatigue failure does not occur at any vibratory load. This differs from knowledge obtained through pad-type load carry tests that fretting fatigue strength decreases with the increase of contact pressure and that it almost saturates under a certain contact pressure. Our detailed observation in the friction-type tests clarified that this mechanism was the low contact pressure narrowing the contact area and a resulting high stress concentration at a local area. The fretting wear rate was explained by the dissipated energy rate per cycle obtained from the measured hysteresis loop between the relative slip range and the tangential contact force. This fretting wear rate per cycle is almost the same as the general adhesion wear rate when energy dissipation per cycle is high, and the former is smaller than the latter as the dissipated energy decreases. Finally, to prevent fretting fatigue and wear, we propose an evaluation design chart of the contact surface of the shroud cover based on our friction-type fretting tests.

scholarly journals Multiaxial High Cycle Fretting Fatigue

2019 ◽  
Vol 300 ◽  
pp. 02002
Author(s):  
José Alexander Araújo ◽  
Gabriel Magalhães Juvenal Almeida ◽  
Fábio Comes Castro ◽  
Raphael Araújo Cardoso
Keyword(s):  
Fretting Fatigue ◽  
Accurate Estimate ◽  
Multiaxial Fatigue ◽  
Fretting Wear ◽  
Critical Plane ◽  
Life Estimation ◽  
Wide Range ◽  
Tools And Techniques ◽  
Critical Direction ◽  
High Cycle Fretting Fatigue

The aim of this work is to show that multiaxial fatigue can be successfully adpted to model fretting problems. For instance, the paper presents (i) the critical direction method, as an alternative to the critical plane concept, to model the crack initiation path under fretting conditions and (ii) studies on size effects considering the influence of incorporating fretting wear on the life estimation. A wide range of new data generated by a two actuators fretting fatigue rig considering Al 7050-T7451 and of Ti-6Al-4V aeronautical alloys is produced to validate these analyses. It is shown that, the development of appropriate tools and techniques to incorporate the particularities of the fretting phenomenon into the multiaxial fatigue problem allow an accurate estimate of the fretting fatigue resistance/life in the medium high cycle regime. Such tools and techniques can be extended to the design of other mechanical components under similar stress enviroments.

Fretting Fatigue Strength Improvement and Life Estimation Methods

2017 ◽  
Vol 2017 (0) ◽  
pp. OS0518
Author(s):  
Toshio HATTORI ◽  
Hiroki NATUME ◽  
Shougo OKAMOTO ◽  
Shouta SUZUKI ◽  
Yuuya TOUJYOU
Keyword(s):  
Fatigue Strength ◽  
Fretting Fatigue ◽  
Estimation Methods ◽  
Life Estimation ◽  
Fatigue Strength Improvement ◽  
Strength Improvement

312 Evaluation of Fretting Fatigue Strength Considering Wear Process

2005 ◽  
Vol 2005.54 (0) ◽  
pp. 75-76
Author(s):  
Naoya NISHIMURA ◽  
Toshio HATTORI ◽  
Minoru YAMASHITA
Keyword(s):  
Fatigue Strength ◽  
Fretting Fatigue ◽  
Wear Process

Fretting Fatigue Strength and Life Estimation Considering the Fretting Wear Process

2007 ◽  
Vol 353-358 ◽  
pp. 882-885 ◽  
Author(s):  
Toshio Hattori ◽  
Naoya Nishimura ◽  
Minoru Yamashita
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Contact Pressure ◽  
Fretting Fatigue ◽  
Fretting Wear ◽  
Estimation Methods ◽  
Stress Intensity Factor Range ◽  
Frictional Stress ◽  
Wear Process

In this paper we present the estimation methods of fretting wear process and fretting fatigue life using this wear process. Firstly the fretting-wear process was estimated using contact pressure and relative slippage. And then the stress intensity factor for cracking due to fretting fatigue was calculated by using contact pressure and frictional stress distributions, which were analyzed by the finite element method. The S-N curves of fretting fatigue were predicted by using the relationship between the calculated stress intensity factor range ( #K) with the threshold stress intensity factor range ( #Kth) and the crack propagation rate (da/dN) obtained using CT specimens of the material. Finaly fretting fatigue tests were conducted on Ni-Mo-V steel specimens. The S-N curves of our experimental results were in good agreement with the analytical results obtained by considering fretting wear process. Using these estimation methods we can explain many fretting troubles in industrial fields.

Experimental Validation of Fretting Fatigue Strength and Fretting Wear Rate at Contact Surface of Turbine-Blade-Shroud Cover

2013 ◽  
Vol 136 (4) ◽  
Author(s):  
Kunio Asai ◽  
Takeshi Kudo ◽  
Hideo Yoda
Keyword(s):  
Fatigue Strength ◽  
Wear Rate ◽  
Contact Pressure ◽  
Contact Force ◽  
Contact Surface ◽  
Fretting Fatigue ◽  
Fretting Wear ◽  
Dissipated Energy ◽  
Normal Contact ◽  
Vibratory Load

In continuously coupled blade structures, fretting fatigue and wear have to be considered as supposed failure modes at the contact surface of the shroud cover, which is subject to steady contact pressure from centrifugal force and the vibratory load of the blade. We did unique fretting tests that modeled the structure of the shroud cover, where the vibratory load is only carried by the contact friction force, i.e., a type of friction. What was investigated in this study are fretting fatigue strength, wear rate, and friction characteristics, such as friction coefficient and slip-range of 12%-Cr steel blade material. The friction-type tests showed that fretting fatigue strength decreases with the contact pressure and a critical normal contact force exists under which fretting fatigue failure does not occur at any vibratory load. This differs from knowledge obtained through pad-type load carry tests that fretting fatigue strength decreases with the increase of contact pressure and that it almost saturates under a certain contact pressure. Our detailed observation in the friction-type tests clarified that this mechanism was the low contact pressure narrowing the contact area and a resulting high stress concentration at a local area. The fretting wear rate was explained by the dissipated energy rate per cycle obtained from the measured hysteresis loop between the relative slip range and the tangential contact force. It was found that the fretting wear rate is smaller than the wear rate obtained by one-way sliding tests, and the former is much smaller than the latter as the dissipated energy decreases. Finally, to prevent fretting fatigue and wear, we propose an evaluation design chart of the contact surface of the shroud cover based on our friction-type fretting tests.

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