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.

Contact fatigue model and life prediction of the compound motion curve-face gear pair

2020 ◽  
Vol 44 (3) ◽  
pp. 440-451
Author(s):  
Chao Lin ◽  
Peilu Li ◽  
Chunjiang He ◽  
Qingkun Xing
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Contact Fatigue ◽  
Tooth Surface ◽  
Gear Pair ◽  
Face Gear ◽  
Fatigue Model ◽  
Contact Fatigue Life ◽  
Five Axis ◽  
Curve Face

Different from the common face gear pair fixed rotation motion between intersecting axes, the compound transmission of the curve-face gear is a new motion form, which can convert rotational motion into rotation and movement motion. To solve the contact fatigue life problem of this new motion form gear pair, a new contact fatigue life calculation method of the compound transmission curve-face gear pair was proposed. Based on the space gear engagement principle and the fracture mechanics theory, the theoretical contact fatigue model of the curve-face gear composite transmission was established. Considering that the contact load for every tooth is time-varying in the half-period of the curve-face gear, the contact fatigue life stage of the curve-face gear was divided into crack initiation and crack growth, and the crack growth fatigue life for each tooth was calculated using the finite element method. The curve-face gear pair was processed in the five-axis NC machining center and the compound transmission experiment platform of the curve-face gear was set up to measure the tooth surface dynamic contact stress, and the overall life of the curve-face gear was predicted. The comparison analysis between theoretical and experimental results verified the correctness of the theoretical contact fatigue calculation model.

Evaluation of contact fatigue life of a wind turbine carburized gear considering gradients of mechanical properties

2018 ◽  
Vol 28 (8) ◽  
pp. 1170-1190 ◽  
Author(s):  
Wei Wang ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Zhangdong Sun
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Heavy Duty ◽  
Initial Residual Stress ◽  
Contact Fatigue Life ◽  
Carburized Gear ◽  
Load Conditions

Case hardening processes such as carburizing are extensively applied in heavy-duty gears used in wind turbines, ships, high-speed rails, etc. Contact fatigue failure occurs commonly in engineering practice, thus reduces reliabilities of those machines. Rolling contact fatigue life of a carburized gear is influenced by factors such as the gradients of mechanical properties and profile of initial residual stress. In this regard, the study of contact fatigue life of carburized gears should be conducted with the consideration of those aspects. In this study, a finite element elastic–plastic contact model of a carburized gear is developed which takes the gradients of hardness and initial residual stress into account. Initial residual stress distribution and the hardness profile along the depth are obtained through experimental measurements. The effect of the hardness gradient is reflected by the gradients of yield strength and fatigue parameters. The modified Fatemi–Socie strain-life criterion is used to estimate the rolling contact fatigue life of the heavy-duty carburized gear. Numerical results reveal that according to the Fatemi–Socie fatigue life criterion, rolling contact fatigue failure of the carburized gear will first initiate at subsurface rather than surface. Compared with the un-carburized gear, the rolling contact fatigue lives of the carburized gear under all load conditions are significantly improved. Under heavy load conditions, the carburized layer significantly reduces the fatigue damage mainly due to the benefit to inhibit the accumulation of plasticity. Influence of the residual stress is also investigated. Under the nominal load condition, compared with the residual stress-free case, the existence of the tensile residual stress causes remarkable deterioration of the rolling contact fatigue life while the compressive residual stress with the same magnitude leads to a moderate growth of the rolling contact fatigue life. As the load becomes heavier when plasticity becomes notable, the influence of the initial residual stress on the life is somewhat weakened.

Finite Element Analysis of the Rolling Contact Fatigue Life of Railcar Wheels

2008 ◽  
Vol 575-578 ◽  
pp. 1461-1466
Author(s):  
Byeong Choon Goo ◽  
Jung Won Seo
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Element Analysis ◽  
Railway Vehicles ◽  
Contact Fatigue Life

Railcar wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles have been more severe in recent years due to speed-up. Therefore, a more precise evaluation of railcar wheel life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking are two major mechanisms of the railcar wheel failure. One of the main sources influencing on the contact zone failure is residual stress. The residual stress in wheels formed during heat treatment in manufacturing changes in the process of braking. Thus the fatigue life of railcar wheels should be estimated by considering both thermal stress and rolling contact. Also, the effect of residual stress variation due to manufacturing process and braking process should be included in simulating contact fatigue behavior. In this paper, an evaluation procedure for the contact fatigue life of railcar wheels considering the effects of residual stresses due to heat treatment, braking and repeated contact load is proposed. And the cyclic stressstrain history for fatigue analysis is simulated by finite element analysis for the moving contact load.

The Effects of Residual Stress of Contact Fatigue Life for Railway Wheels

2005 ◽  
Vol 297-300 ◽  
pp. 115-121 ◽  
Author(s):  
Jung Won Seo ◽  
Byeong Choon Goo ◽  
Heung Chai Chung ◽  
Jae Boong Choi ◽  
Young Jin Kim
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Fatigue Life ◽  
Contact Fatigue ◽  
Contact Load ◽  
Evaluation Procedure ◽  
Railway Wheel ◽  
Railway Vehicles ◽  
Contact Fatigue Life ◽  
Railway Wheels

Railway wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles became more severe in recent years due to the increase of speed. Therefore, a more precise evaluation of railway wheel life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking are two major mechanisms of the railway wheel failure. One of the main sources of the contact zone failure is the residual stress. The residual stress on wheel is formed during the manufacturing process which includes a heat treatment, and then, is changed in the process of braking which results in wheel/rail contact stress and thermal stress. In this paper, an evaluation procedure for the contact fatigue life of railway wheel including residual stress is proposed. Also, the cyclic stress history for fatigue analysis is simulated by applying finite element analysis for the moving contact load. As a result, a fatigue life estimation methodology is proposed for railway wheels which includes the effects of residual stresses due to heat treatment, braking and repeated contact load, respectively.

The Effects of Residual Stress of Contact Fatigue Life for Railway Wheels

2005 ◽  
pp. 115-121
Author(s):  
Jung Won Seo ◽  
Byeong Chun Goo ◽  
Heung Chai Chung ◽  
Jae Boong Choi ◽  
Young Jin Kim
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Contact Fatigue ◽  
Contact Fatigue Life ◽  
Railway Wheels

Effect of Metal Removal and Initial Residual Stress on Contact Fatigue Life

2005 ◽  
Vol 29 (2) ◽  
pp. 341-349
Author(s):  
Hun-Mu Hur ◽  
Byeong-Choon Goo ◽  
Jae-Boong Choi ◽  
Young-Jin Kim ◽  
Jung-Won Seo
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Metal Removal ◽  
Contact Fatigue ◽  
Initial Residual Stress ◽  
Contact Fatigue Life

Analysis of Non-Standard Gear Contact Fatigue Life

2013 ◽  
Vol 300-301 ◽  
pp. 1227-1230
Author(s):  
Ying Qiang Xu ◽  
Jian Hua Zhao ◽  
Zu Heng Shi
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Contact Fatigue ◽  
Testing Time ◽  
The Finite Element Method ◽  
Life Test ◽  
Contact Fatigue Life ◽  
Gear Contact ◽  
Fatigue Life Test ◽  
Test Process

A model of gear contact has been established based on Hertz theory in this thesis, Analysis of non-standard gear contact fatigue life test process . For ha* take 1,1.15,1.25 and c* take 0.25,0.5 respectively ,the gear generates contact fatigue failure, then calculate the meshing ratio under different tooth high coefficients, and gear pairs state with fatigue testing time by the finite element method and orthogonal test. These data are compared with the results of specific experiments verified. They description that tooth height coefficients and headspace coefficients change have a great impact on gear contact fatigue life.

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