A general model for prediction of deformation from initial residual stress

2020 ◽  
Vol 109 (3-4) ◽  
pp. 1093-1101
Author(s):  
Yamin Zhu ◽  
Kuanmin Mao ◽  
Xunxing Yu
Keyword(s):  
Residual Stress ◽  
General Model ◽  
Initial Residual Stress

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.

scholarly journals Simulation of Thermal Stress and Fatigue Life Prediction of High Speed Steel Work Roll during Hot Rolling Considering the Initial Residual Stress

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 966 ◽  
Author(s):  
Kejun Hu ◽  
Fuxian Zhu ◽  
Jufang Chen ◽  
Nao-Aki Noda ◽  
Wenqin Han ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Fatigue Life ◽  
Hot Rolling ◽  
Work Roll ◽  
Roll Surface ◽  
Initial Residual Stress ◽  
Thermal Fatigue Life ◽  
Cooling Conditions ◽  
Roll Temperature

Considerable residual stress is produced during heat treatment. Compressive residual stress at the shell is conductive to improving the thermal fatigue life of a work roll, while tensile stress in the core could cause thermal breakage. In hot rolling, thermal stress occurs under the heating-cooling cycles over the roll surface due to the contact with the hot strip and water spray cooling. The combination of thermal stress and residual stress remarkably influences the life of a work roll. In this paper, finite element method (FEM) simulation of hot rolling is performed by treating the residual stress as the initial stress. Afterwards, the effects of the initial roll temperature and cooling conditions on thermal stress considering the initial residual stress are discussed. Lastly, the thermal fatigue life of a work roll is estimated based on the strain life model. The higher initial roll temperature causes a higher temperature but a lower compressive thermal stress at the roll surface. The surface temperature and compressive stress increase significantly in the insufficient cooling conditions, as well as the center tensile stress. The calculation of the fatigue life of a work roll based on the universal slopes model according to the 10% rule and 20% rule is reasonable compared with experimental results.

Residual Stress Regenerated on Low Plasticity Burnished Inconel 718 Surface After Initial Turning Process

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Yang Hua ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Jiaming Jiang
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Analytical Model ◽  
Inconel 718 ◽  
Plastic Behavior ◽  
Residual Stress Field ◽  
Workpiece Material ◽  
Elastic Plastic ◽  
Initial Residual Stress ◽  
Low Plasticity Burnishing

Abstract Low plasticity burnishing (LPB) has been extensively employed in aero-industry to enhance fatigue performance of machined components by introducing compressive residual stress. Effects of various parameters on the residual stress field induced by low plasticity burnishing have been investigated by many researchers. However, initial residual stresses induced by machining are one of the important factors which affect the residual stress regenerated by the LPB process. The present work aims to develop an analytical model which takes into account the initial residual stress and burnishing parameters to predict residual stress field of workpiece material Inconel 718 based on Hertz contact theory and elastic–plastic theory. Initial residual stress fields were produced by turning of Inconel 718 and were measured by using X-ray diffraction technique. Two types of material constitutive models such as the linear hardening model and isotropic–kinematic model were employed to describe the elastic–plastic behavior of workpiece material Inconel 718. An analytical study was performed to analyze the effect of the initial residual stress field and burnishing parameters on residual stress induced by low plastic burnishing. The results of analytical model were verified by conducting the LPB experiments on initial turned Inconel 718. The results showed that the shape and magnitude of the residual stress field obtained with considering the effect of initial residual stress field was in good accordance with experimental measurements.

The Influence of Initial Residual Stress State on the Steady State Behaviour of Cyclically Loaded Coupled Contacts

2011 ◽  
Author(s):  
Robert Flicek ◽  
Daniele Dini ◽  
David A. Hills
Keyword(s):  
Residual Stress ◽  
Frictional Contact ◽  
Contact Problems ◽  
Coupled Problems ◽  
Strongly Coupled ◽  
Initial Residual Stress ◽  
Residual Stress State ◽  
Initial Load ◽  
State Behaviour ◽  
Steady State Behaviour

The Melan’s shakedown theorem applies to uncoupled frictional contact problems, but is known formally not to apply in the case of coupled contacts. In this paper we look at two example coupled problems (one very strongly coupled) in detail and show that, in fact, for these specific cases, shakedown does occur for a range of initial load states.

Residual Stress Measurement of Sealing Glass Based on Optical Fiber Sensing Technology

2018 ◽  
Author(s):  
Li Mingze ◽  
Fan Zhichun ◽  
Diao Xingzhong ◽  
Yan He
Keyword(s):  
Residual Stress ◽  
Optical Fiber ◽  
Stress Measurement ◽  
Pressure Vessels ◽  
Residual Stress Measurement ◽  
Initial Residual Stress ◽  
Fiber Sensing ◽  
Optical Fiber Sensing ◽  
The Impact ◽  
Sealing Glass

Metal-to-glass electrical penetration assemblies (EPA) are highly sophisticated equipment and have been used for electrical connection in containment structures or pressure vessels in nuclear plants because of their high temperature resistance and good hermeticity. One important factor to keep hermeticity and reliability can be attributed to the initial residual stress in sealing glass of metal-to-glass EPA. If the residual stress is too high, small defects easily take place in the sealing materials. An insufficient prestress also cannot meet the requirement of high pressure application. To study the influence of residual stress on hermeticity, we developed a novel method of residual stress measurement in metal-glass sealing based on an embedded optical fiber sensor. The fiber Bragg grating (FBG) sensor was embedded in the glass material during the EPA manufacturing, and the residual stress along the grating could be retrieved via optical fiber sensing technique. Basing on our existing metal-glass sealing technique, the initial residual stress could be modulated by changing the sealing process, then the change of different initial residual stress was measured by the embedded FBG, through which the impact of residual stress on metal-glass sealing hermeticity could be finally revealed. A finite element model was established basing on linear elastic theory, then the localized stress along the FBG and the global stress distribution had been investigated theoretically. Taking the stress measuring by FBG as a breakthrough point, the effect of initial residual stress on sealing hermeticity was studied experimentally. The results showed that the residual stress should be an important assessment indicator to metal-to-glass sealing. This research also provided a new approach to optimize EPA manufacture.

Investigation on deformation of single-sided stringer parts based on fluctuant initial residual stress

2019 ◽  
Vol 271 ◽  
pp. 623-633 ◽  
Author(s):  
Yinfei Yang ◽  
Xiaoyue Li ◽  
Liang Li ◽  
Ning He ◽  
Guolong Zhao ◽  
...  
Keyword(s):  
Residual Stress ◽  
Initial Residual Stress

scholarly journals Micro-Hardness and Residual Stress Relaxation of 2024 T351 Aluminum Alloy

2011 ◽  
Vol 462-463 ◽  
pp. 343-348 ◽  
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi ◽  
Rizal Zahari
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Shot Peening ◽  
X Ray Diffraction ◽  
Initial State ◽  
Load Amplitude ◽  
Initial Residual Stress ◽  
Residual Stress Relaxation ◽  
Two Stages

The residual stress relaxation can be divided into two stages: The first cycle relaxation and the following cycles. In both stages, residual stress relaxed considerably from the initial state. The aim of this study is to investigate the residual stress relaxation and microhardness reduction after first and second cyclic load. A 2024 T351 aluminum alloy specimens were shot peened into three shot peening intensities. The fatigue test for first and second cyclic loads of two loads 15.5 kN and 30 kN was performed. The initial residual stress and residual stress after the first and second cycle stress was measured for the three shot peening intensities using X-ray diffraction. Microhardness test was performed for each specimen. The results showed that the residual stress relaxation for first cycle was reached more than 40% of the initial residual stress and it depends on the load amplitude, and microhardness decreased for the first cycle reached 22% and also it depended on load amplitude.

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