Observation of Cracks of PEEK Polymer Thrust Bearings under Rolling Contact Fatigue in Water

2016 ◽  
Vol 703 ◽  
pp. 172-177 ◽  
Author(s):  
Xiao Chen Shi ◽  
Masaya Orito ◽  
Yuji Kashima ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida
Keyword(s):  
Corrosion Resistance ◽  
Friction Coefficient ◽  
Cross Sections ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Light Weight ◽  
Low Friction ◽  
High Corrosion Resistance ◽  
Thrust Bearings

Considering the advantages on light weight, low friction coefficient, high corrosion resistance and electric insulation, polymer bearings are widely used under certain environments, where the toughness like metal bearings is not necessary. In our previous study, it was concluded that the main reason for PEEK thrust bearings failure in water was flaking due to surface crack propagation. In the present study, crack observations were made on groove surfaces and cross sections along both radial and rolling directions in order to find the relation between cracks and flaking failures.

Crack Observation of PPS Polymer Thrust Bearings under RCF Test in Water

2016 ◽  
Vol 703 ◽  
pp. 178-182
Author(s):  
Xiao Chen Shi ◽  
Masatoshi Ando ◽  
Yuji Kashima ◽  
Katsuyuki Kida
Keyword(s):  
Crack Propagation ◽  
Cross Sections ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Low Friction ◽  
High Corrosion Resistance ◽  
Thrust Bearings ◽  
Bearing Failures ◽  
Polymer Bearing

Polymer bearings are widely used under certain environments due to the advantages on light weight, low friction coefficient, high corrosion resistance and electric insulation. The main reason for polymer bearing failures in water was formation of flakings due to crack propagation. However, the mechanism of fatigue crack propagation in polymer material under rolling contact condition has not been clearly explained yet. In the present study, detailed crack observations were made on cross sections along both radial and rolling directions after RCF (Rolling Contact Fatigue) test in water using PPS thrust bearings.

Effect of PTFE Retainer on Friction Coefficient in Polymer Thrust Bearings under Dry Contact

2013 ◽  
Vol 683 ◽  
pp. 90-93 ◽  
Author(s):  
Koshiro Mizobe ◽  
Takashi Honda ◽  
Hitonobu Koike ◽  
Edson Costa Santos ◽  
Yuji Kashima ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Low Friction ◽  
Friction Forces ◽  
Thrust Bearings ◽  
Dry Contact

Polyetheretherketone (PEEK) is a tough semi-crystalline thermoplastic polymer with excellent mechanical properties. While abilities of polyphenylenesulfide (PPS) are similar to PEEK, former material cost was lower than later. Polytetrafluoroethylene (PTFE) is well known because of its low friction coefficient and self lubrication ability. The objective of this study is to observe the friction coefficient of hybrid bearings, PTFE retainer sandwiched with PPS-races or PEEK-races. Rolling contact fatigue tests were performed and in situ friction forces wear measured. It is concluded that the PTFE retainer reduced friction coefficient.

Effect of Groove Geometry on Rolling Contact Fatigue of PEEK Thrust Bearings in Water

2016 ◽  
Vol 878 ◽  
pp. 117-121 ◽  
Author(s):  
Masaya Orito ◽  
Katsuyuki Kida ◽  
Yuuki Hashizume ◽  
Masayuki Ishida ◽  
Koshiro Mizobe ◽  
...  
Keyword(s):  
Cross Sections ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Light Weight ◽  
Design Standards ◽  
Thrust Bearings ◽  
Manufacture Process ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone

Bearings have been used in various environments. Recently, small and light-weight bearings are developed in order to downsize mechanical components. Polymer bearings, such as PEEK (Poly-Ether-Ether-Ketone), PTFE (Poly-Tetra Fluoro-Ethylene) and PPS (Poly-Phenylene-Sulfide-Resin), are designed because of advantages of light weight, high corrosion resistance and self-lubricating. However, industrial design standards of these bearings have not been established yet, i.e., the relation between working conditions, shape, geometry, and lives of bearing components under RCF (Rolling Contact Fatigue) is not fully understood as well as crack propagation, wear and/or failure. In this study, we focused on the manufacture process of groove curvature decreasing contact stress, and observed cracks and flaking failures on groove surfaces and cross sections. Based on these observations, we investigated the relation between the groove geometry and lives of all-PEEK thrust bearings in water.

Effect of Rotation Speeds on Friction Coefficients of PPS Race-PTFE Retainer Hybrid Polymer Thrust Bearings under Dry Contact

2013 ◽  
Vol 418 ◽  
pp. 205-208 ◽  
Author(s):  
Xiao Chen Shi ◽  
Koshiro Mizobe ◽  
Yuji Kashima ◽  
Katsuyuki Kida
Keyword(s):  
Friction Coefficient ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Wear Loss ◽  
Hybrid Polymer ◽  
Thrust Bearings ◽  
Dry Contact ◽  
Thrust Load

In the previous study on PPS race-PTFE retainer Hybrid polymer bearings, the relationship between thrust load, rotation speeds and wear loss under dry condition was investigated. It was found that the wear loss obviously changed under the thrust load ranging from 400N to 500N at the rotation speeds of 450rpm and 600rpm. The object of this study is to observe the friction coefficient at the rotation speeds ranging from 450rpm and 600N under thrust load of 400N. Rolling contact fatigue tests were performed and it was concluded that friction coefficient decreases with the rotation speeds.

Research on the Approach for the Assessment of Subsurface Rolling Contact Fatigue Damage

2013 ◽  
Vol 395-396 ◽  
pp. 845-851
Author(s):  
Xiao Feng Qin ◽  
Da Le Sun ◽  
Li Yang Xie
Keyword(s):  
Shear Stress ◽  
Friction Coefficient ◽  
Fatigue Damage ◽  
Stress Ratio ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Critical Stresses ◽  
Orthogonal Shear Stress

In this paper, the distribution of different critical stresses, which were used in previous correlation articles for the assessment of subsurface rolling contact fatigue damage, was analyzed. The rationality of orthogonal shear stress was selected as the key stress controlling the subsurface rolling contact fatigue damage was clarified. Base on the linear fatigue damage accumulative theory and the modification equation for the range of asymmetrical stress, the influence of friction on subsurface rolling contact fatigue damage was studied. The results show that the subsurface orthogonal shear stress is a completely symmetrical stress when the friction coefficient is zero, while it is an asymmetrical stress with considering the friction. The stress ratio of subsurface orthogonal shear stress and subsurface rolling contact fatigue damage is increased with the increasing of friction.

Subsurface Stress Distribution and Failure of PPS Thrust Bearings under Rolling Contact Fatigue in Water

2019 ◽  
Vol 814 ◽  
pp. 152-156 ◽  
Author(s):  
Xiao Chen Shi ◽  
Akihiro Adachi ◽  
Katsuyuki Kida
Keyword(s):  
Fatigue Crack ◽  
Stress Distribution ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Polymer Materials ◽  
Thrust Bearings ◽  
Subsurface Stress

In recent years, environments of bearings and polymer materials have been more and more attractive due to several advantages against ordinary metal material. However, there is still room for the further study about strength of polymer bearings. One of questions is the mechanism of fatigue crack propagation, which is the main cause of the damage of polymer bearings under rolling contact with lubricant, like water. In this study, subsurface stress distribution and failure of PPS thrust bearings under rolling contact fatigue in water are discussed to understand the detail of the crack propagation.

scholarly journals Dry Rolling/Sliding Wear of Bainitic Rail Steels under Different Contact Stresses and Slip Ratios

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4678
Author(s):  
Jiapeng Liu ◽  
Yingqi Li ◽  
Yinhua Zhang ◽  
Yue Hu ◽  
Lubing Shi ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Abrasive Wear ◽  
Contact Stress ◽  
Wear Mechanism ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wear Loss ◽  
Fatigue Wear ◽  
Slip Ratio

This study aims to deeply understand the effect of contact stress and slip ratio on wear performances of bainitic rail steels. The results showed that the wear loss increased as the contact stress and slip ratio increased. Based on the surface damage morphology and microstructural analyses, it revealed that the rolling contact fatigue wear mechanism played a significant role under the low slip ratio, but the dominant wear mechanism transferred to the abrasive wear at the high slip ratio. Meanwhile, the bainitic steel specifically presented worse wear resistance under the abrasive wear mode. Compared with the influence of a slip ratio, the increase in contact stress led to severer plastic flows and contributed to the propagation of cracks. In addition, the contact stress and slip ratio had the opposite effect on the friction coefficient, that is, the friction coefficient of bainitic steels behaved the inverse proportion with the contact stress, but positive proportion with the slip ratio. At last, the increase in slip ratio had more significant effect on the reduction of retained austenite (RA) than the enlargement of contact stress due to the fact that the RA would probably be removed before the martensitic transformation occurred under the abrasive wear mechanism.

Internal Shear Stress Distribution and Subsurface Cracks of PPS Thrust Bearings under Rolling Contact Fatigue in Water

2020 ◽  
Vol 858 ◽  
pp. 101-105
Author(s):  
Syunsuke Mizozoe ◽  
Katsuyuki Kida
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Crack Propagation ◽  
Contact Stress ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Subsurface Crack ◽  
Thrust Bearings ◽  
Subsurface Cracks

In this study, crack propagation in PPS thrust bearings under rolling contact fatigue (RCF) in water was observed, and relation between subsurface crack and internal shear stress parallel to the surface was investigated. It was found the cause of flaking was subsurface crack. They were evaluated in terms of contact stress and friction between their faces. It was discovered that subsurface cracks distributed around shear stress peak, and flaking failure was dominated by subsurface shear stress.

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