scholarly journals Investigation on stress microcycles and mild wear mechanism in gear contact fatigue

2021 ◽  
Author(s):  
Ye Zhou ◽  
Caichao Zhu ◽  
Huaiju Liu ◽  
Houyi Bai ◽  
Xiaona Xu
Keyword(s):  
Wear Mechanism ◽  
Contact Fatigue ◽  
Mild Wear ◽  
Gear Contact

scholarly journals Investigation on stress micro-cycles and mild wear mechanism in gear contact fatigue

2021 ◽  
Author(s):  
Ye Zhou ◽  
Caichao Zhu ◽  
Huaiju Liu ◽  
Houyi Bai ◽  
Xiaona Xu
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Contact Fatigue ◽  
Sliding Contact ◽  
Premature Failure ◽  
Mild Wear ◽  
Safety And Reliability ◽  
Contact Fatigue Life ◽  
Stress Cycles ◽  
Gear Contact

Gear contact fatigue is becoming a primary limitation for the growing demand of power density and service life in gear-driven equipment. The unchecked surface fatigue crack could further cause premature failure and put a serious risk to the safety and reliability of mechanical systems. In this work, an attempt is made to investigate the effects of rolling-sliding and mild wear on contact fatigue behavior. A comprehensive contact model is developed to capture the variation instantaneous pressure and stress field is calculated with the transient mixed EHL approach. Rolling-sliding contact is simulated with the time-varying roughness topography updated by Archard wear equation. The stress cycles are extracted and the relative contact fatigue life is obtained by using Zaretsky criterion. Results suggest that in rolling-sliding contact the contact fatigue life is obviously lower compared with pure rolling. The increases in the number and amplitude of stress micro-cycles is found to be the main contributors to the reduction of fatigue life. Mild wear tends to smooth the surface, subsequently mitigates the stress concentration and reduces stress cycles, then decrease the risk of surface contact fatigue.

Research on Gear Contact Fatigue Stress Test

2011 ◽  
Vol 86 ◽  
pp. 825-828
Author(s):  
Tie Wang ◽  
Hong Mei Li ◽  
Rui Liang Zhang ◽  
Zhi Fei Wu
Keyword(s):  
Damage Accumulation ◽  
Stress Test ◽  
Contact Fatigue ◽  
Test Method ◽  
Fatigue Stress ◽  
Accumulation Curve ◽  
Limit Value ◽  
Fatigue Damage Accumulation ◽  
Gear Contact ◽  
The Cost

This paper put forward the rapid measure method of the gear contact fatigue stress value with a few gear samples, which can get the estimated value of the gear fatigue limit value precisely and rapidly. And the gear fatigue life curve and fatigue damage accumulation curve are simulated by MATLAB. Comparing with the traditional test method, this method can reduce the cost and save the time.

A stochastic prediction of roughness evolution in dynamic contact modelling applied to gear mild wear and contact fatigue

2019 ◽  
Vol 140 ◽  
pp. 105854 ◽  
Author(s):  
Raynald Guilbault ◽  
Sébastien Lalonde
Keyword(s):  
Contact Fatigue ◽  
Dynamic Contact ◽  
Mild Wear ◽  
Contact Modelling

An Approach for the Gear Rolling Contact Fatigue Acceleration

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Sheng Li ◽  
Jeremy J. Wagner
Keyword(s):  
Film Thickness ◽  
Crack Formation ◽  
Crack Nucleation ◽  
Rotational Velocity ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Time Period ◽  
Gear Contact ◽  
Gear Rolling

This study proposes an approach for the acceleration of the experimental gear rolling contact fatigue (RCF) crack formation. By increasing the rotational velocity of a gear pair, the RCF experimental time period is reduced. However, the film thickness is increased to improve the fatigue performance, to counteract which it is proposed to raise the lubricant temperature to reduce the film thickness. A physics-based gear contact fatigue model is used to quantify and offset the effects of the rotational velocity and the lubricant temperature on the crack nucleation.

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.

Evaluation of Contact Fatigue Life of a Wind Turbine Gear Pair Considering Residual Stress

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Heli Liu ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Haifeng He ◽  
Peitang Wei
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Stress State ◽  
Wind Turbine ◽  
Axial Stress ◽  
Contact Fatigue ◽  
Tooth Surface ◽  
Gear Pair ◽  
Contact Fatigue Life ◽  
Gear Contact

Contact fatigue is a main fatigue mode of gears such as those used in wind turbines, due to heavy duties occurring in engineering practice. The understanding of the gear contact fatigue should be based on the interaction between the local material strength and the stress state. Under the rolling–sliding motion, the multi-axial stress state makes the gear contact fatigue problem more complicated. A numerical contact model is proposed to evaluate the contact fatigue life of an intermediate parallel gear stage of a megawatt level wind turbine gearbox. The gear meshing theory is applied to calculate the geometry kinematics parameters of the gear pair. The gear contact is assumed as a plane strain contact problem without the consideration of the influence of the helical angle. The quasi-static tooth surface load distribution is assumed along the line of action. The elastic mechanics theory is used to calculate the elastic stress field generated by surface tractions. The discrete convolute, fast Fourier transformation method is applied to estimate the subsurface stresses distributions. In order to describe the time-varying multi-axial stress states during contact, the Matake, Findley, and Dang Van multi-axial fatigue criteria are used to calculate the critical planes and equivalent stresses. Both the statistic and the deterministic fatigue life models are applied by choosing the Lundberg–Palmgren (LP), Zaretsky models, respectively. The effect of the residual stress distribution on the contact fatigue initiation lives is discussed. In addition, the crack propagation lives are estimated by using the Paris theory.

Continuous damage-based Voronoi finite element analysis of contact fatigue of a wind turbine gear

2019 ◽  
Vol 233 (10) ◽  
pp. 1483-1495
Author(s):  
Peitang Wei ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Haifeng He
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Mechanical Response ◽  
Fatigue Behavior ◽  
Maximum Shear Stress ◽  
Contact Fatigue ◽  
Damage Mechanism ◽  
Mechanical Transmission ◽  
Element Analysis ◽  
Gear Contact

Contact fatigue failures of gears, especially those used in heavy duty conditions such as wind turbine gears, become important issues in mechanical transmission industry. In the present work, a continuous damage mechanism and Voronoi-based finite element model is developed to investigate the contact fatigue of a wind turbine gear. Plane strain assumption is adopted to simplify the gear contact model. Voronoi tessellations are utilized to represent the microstructure topology of the gear material, and continuous damage mechanism is implemented to reflect the material degradation within critical substrate area. With the developed framework, the contact pressure distribution, intergranular mechanical response and the progressive fatigue damage at the grain boundaries during repeated gear meshing are evaluated and discussed in detail. The depths of the maximum shear stress reversal and the crack initiation agree well with previously reported findings. The influence of microstructure on the gear contact fatigue behavior is also investigated.

The mild wear mechanism of nodular iron

Wear ◽  
1969 ◽  
Vol 13 (4-5) ◽  
pp. 337-343 ◽  
Author(s):  
R.S. Montgomery
Keyword(s):  
Wear Mechanism ◽  
Nodular Iron ◽  
Mild Wear
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