Experimental and Fracture Mechanics Study of the Pit Formation Mechanism Under Repeated Lubricated Rolling-Sliding Contact: Effects of Reversal of Rotation and Change of the Driving Roller

1997 ◽  
Vol 119 (4) ◽  
pp. 788-796 ◽  
Author(s):  
Y. Murakami ◽  
C. Sakae ◽  
K. Ichimaru ◽  
T. Morita
Keyword(s):  
Fatigue Crack ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Surface Damage ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Sliding Contact ◽  
Hydraulic Pressure ◽  
Pit Formation ◽  
Original Crack

Five rolling contact fatigue tests, Tests {1}–{5} have been conducted. In Tests {1}–{3}, when a fatigue crack was initiated on the surface of a follower, the test was halted. Then, in Test {1} the rotating direction was reversed. In Test {2} the follower and driver were interchanged, and in Test {3} the test was continued unchanged. In Test {3} the original crack grew to a pit. In Tests {1} and {2} the original crack immediately stopped propagating. In Tests {4} and {5}, mating with a harder roller, a softer roller was used as the follower in Test {4} and as the driver in Test {5}. A typical pit occurred in Test {4}. In Test {5}, surface damage substantially different from a typical pit was generated. Based on these experimental results, a 3-D crack analysis including the effect of frictional force on the contact surface and oil hydraulic pressure on crack surfaces, was conducted to elucidate the mechanisms of pit formation and surface damage in contact fatigue.

Observation of Tribological Fatigue Fracture on PEEK Shaft with Artificial Defect under One-Point Rolling Contact by Using 2.5D Layer Method

2019 ◽  
Vol 814 ◽  
pp. 314-319 ◽  
Author(s):  
Hitonobu Koike ◽  
Shuta Yamada ◽  
Gang Deng ◽  
Koshiro Mizobe ◽  
Takuto Yamada ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Fracture ◽  
Rolling Contact Fatigue ◽  
Rolling Direction ◽  
Point Contact ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Artificial Defect ◽  
Depth Direction

In order to explore the mechanism of tribological fatigue fracture in PEEK (Poly-ether-ether-ketone) polymer mechanical element application, one-point contact type RCF (rolling contact fatigue) tests were carried out by using a PEEK shaft with an artificial defect. An alumina ball contacted a PEEK shaft specimen under maximum Hertzian stress 380 MPa. Flaking and internal fatigue crack propagation under the rolling track of the tested PEEK shaft were investigated through 2.5D layer observation method. The main fatigue crack occurred near the artificial defect on the rolling track of the PEEK shaft, and propagated into depth direction. In addition, the main fatigue crack branched due to internal shear stress. The branching crack as internal fatigue crack propagated into the ball’s rolling direction. After the linkage of the branching crack and another semicircular surface crack, the horseshoe-shaped flaking as tribological fatigue fracture occurred on the rolling track of the PEEK shaft.

Influence on Tribological Behavior of PEEK Composite Film Layer on PEEK-PTFE Bearings with Artificial Defect in Dry Condition

2021 ◽  
Vol 904 ◽  
pp. 243-249
Author(s):  
Hitonobu Koike ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida
Keyword(s):  
Composite Film ◽  
Tribological Behavior ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Artificial Defect ◽  
Peek Composite ◽  
Film Layer ◽  
Number Of Cycles

In order to explore influence on tribological behavior of PEEK composite film layer in PEEK-PTFE composite radial alumina ball bearings, rolling contact fatigue tests were performed by using the PEEK bearing’s inner rings with the artificial defects in dry condition. When rotation speed and applied load were 600 rpm and 98 N, the number of cycles of the PEEK-PTFE bearings reached 1.0×107 fatigue cycles. The artificial defects with 0.02 mm depth on the raceway surface of the PEEK inner ring was covered with PEEK composite film accumulation.

A Predictive Rolling Contact Fatigue Crack Growth Model: Onset of Branching, Direction, and Growth—Role of Dry and Lubricated Conditions on Crack Patterns

2002 ◽  
Vol 124 (4) ◽  
pp. 680-688 ◽  
Author(s):  
M. C. Dubourg ◽  
V. Lamacq
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Interfacial Crack ◽  
Rolling Contact ◽  
Propagation Behavior ◽  
Branch Formation ◽  
Complex Crack ◽  
Crack Growth Model

Complex crack networks are initiated in rails under Rolling Contact Fatigue. This paper attempts to model the RCF crack propagation with a particular emphasis on the branching conditions and the parameters that play a role on them. The numerical tool proposed rests on the combination of the author’s RCF model, Hourlier and Pineau’s criterion for the branch prediction and experimental data and the corresponding models for fatigue crack extension that are derived from a Joint European project. Parametric studies on the influence of (i) residual stresses, (ii) both interfacial crack and wheel/rail contact frictional effects, (iii) neighboring crack are conducted to reach a better understanding of the RC crack propagation behavior and more particularly the branch conditions, i.e., the length of the primary crack prior to branch formation and the branch direction.

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 Lubricant on Surface Rolling Contact Fatigue Cracks

2010 ◽  
Vol 97-101 ◽  
pp. 793-796 ◽  
Author(s):  
Khalil Farhangdoost ◽  
Mohammad Kavoosi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Cracks ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Element Analysis ◽  
Crack Face ◽  
Hertzian Contact Stress ◽  
Model Of Friction

This study performed the finite element analysis of the cycle of stress intensity factors at the surface initiated rolling contact fatigue crack tip under Hertzian contact stress including an accurate model of friction between the faces of the crack and the effect of fluid inside the crack. A two-dimensional model of a rolling contact fatigue crack has been developed with FRANC-2D software. The model includes the effect of Coulomb friction between the faces of the crack. The fluid in the crack was assumed not only to lubricate the crack faces and reduce the crack face friction coefficient but also to generate a pressure.

Experimental Investigations Upon Fatigue Life of Circular Contacts With Transversal Furrow

2005 ◽  
Author(s):  
Delia F. Cerlinca ◽  
Emanuel N. Diaconescu
Keyword(s):  
Fatigue Life ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Geometric Parameters ◽  
Rolling Contact ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Contact Fatigue Life

Rolling contact fatigue depends essentially on both surface and subsurface populations of defects. First, this paper describes experimental results obtained in rolling contact fatigue tests in the presence of a furrow oriented transversally to the race-way. Then an attempt to predict theoretically the effect of geometric parameters of the furrow upon contact fatigue life is described.

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