Influence of Roughness Parameters Skewness and Kurtosis on Fatigue Life Under Mixed Elastohydrodynamic Lubrication Point Contacts

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Xiao-Liang Yan ◽  
Xiao-Li Wang ◽  
Yu-Yan Zhang
Keyword(s):  
Fatigue Life ◽  
Elastohydrodynamic Lubrication ◽  
Von Mises Stress ◽  
Maximum Pressure ◽  
Point Contacts ◽  
Roughness Parameters ◽  
Numerical Studies ◽  
Non Gaussian ◽  
Von Mises ◽  
Skewness And Kurtosis

The numerical studies on the influences of surface parameters skewness and kurtosis on tribological characteristics under mixed elastohydrodynamic lubrication (mixed EHL) conditions are extended to fatigue life. Non-Gaussian rough surfaces are generated numerically with given autocorrelation function, skewness, and kurtosis. The results show that the maximum pressure increases as the skewness increases, however its variation with kurtosis is closely related to skewness. Similar trends to that of the maximum pressure are observed for the maximum von Mises stress. The fatigue life decreases as the skewness increases, however it undergoes apparent fluctuations with the increase of kurtosis. As the kurtosis increases, the influence of skewness on fatigue life becomes more significant, and vice versa.

Theoretical analysis of a rolling-sliding elastohydrodynamic lubrication line contact with a subsurface inclusion

2019 ◽  
Vol 233 (8) ◽  
pp. 1197-1207
Author(s):  
Armando Félix Quiñonez ◽  
Guillermo E Morales Espejel
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Element Model ◽  
Von Mises Stress ◽  
Transient Effects ◽  
Mean Velocity ◽  
The Matrix ◽  
Soft Inclusion ◽  
The Mean ◽  
Von Mises ◽  
Fully Coupled

This work investigates the transient effects of a single subsurface inclusion over the pressure, film thickness, and von Mises stress in a line elastohydrodynamic lubrication contact. Results are obtained with a fully-coupled finite element model for either a stiff or a soft inclusion moving at the speed of the surface. Two cases analyzed consider the inclusion moving either at the same speed as the mean velocity of the lubricant or moving slower. Two additional cases investigate reducing either the size of the inclusion or its stiffness differential with respect to the matrix. It is shown that the well-known two-wave elastohydrodynamic lubrication mechanism induced by surface features is also applicable to the inclusions. Also, that the effects of the inclusion become weaker both when its size is reduced and when its stiffness approaches that of the matrix. A direct comparison with predictions by the semi-analytical model of Morales-Espejel et al. ( Proc IMechE, Part J: J Engineering Tribology 2017; 231) shows reasonable qualitative agreement. Quantitatively some differences are observed which, after accounting for the semi-analytical model's simplicity, physical agreement, and computational efficiency, may then be considered as reasonable for engineering applications.

scholarly journals Design and Fatigue Optimization of Drive Shaft

2021 ◽  
Vol 9 (VIII) ◽  
pp. 194-203
Author(s):  
Ashish Bawkar
Keyword(s):  
Fatigue Life ◽  
Natural Frequency ◽  
Drive Shaft ◽  
Von Mises Stress ◽  
Hollow Shaft ◽  
Design And Optimization ◽  
The Road ◽  
Increasing Demand ◽  
Von Mises ◽  
Fea Analysis

This work aims towards the design and optimization of the drive shaft as there is increasing demand for weight reduction in an automobile vehicle. The drive shaft is basically a torque transmitting element which transmit the torque from the differential gearbox to the respective wheels. In general, the drive shafts are subjected to fluctuating loads as the torque requirement changes according to the road conditions. Due to this, the drive shaft should be designed considering fatigue failure. The Maruti Suzuki Ertiga model is chosen for design and optimization of the drive shaft. For the fatigue life predicting of the drive shaft, the S-N curve approach is used. Furthermore, the inner diameter of the shaft is varied to obtain the optimized diameter of a hollow shaft which can withstand these fluctuating loads without failure. Along with fatigue life prediction, the natural frequency of the hollow shaft is also calculated. Furthermore, the parametric analysis is carried out of fatigue FOS, Von mises stress, weight and natural frequency of the shaft by varying the diameter ratio of the hollow shaft, and the nature of variation of these parameters are plotted in their respective graphs. The design is validated by performing FEA analysis for each case of a hollow shaft using Ansys software. Finally, from the FEA analysis we conclude that the optimized dimensions of the hollow drive shaft are safe.

Plasto-Elastohydrodynamic Lubrication in Point Contacts for Surfaces With Three-Dimensional Sinusoidal Waviness and Real Machined Roughness

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Tao He ◽  
Ning Ren ◽  
Dong Zhu ◽  
Jiaxu Wang
Keyword(s):  
Plastic Deformation ◽  
Rough Surface ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Operating Conditions ◽  
Von Mises Stress ◽  
Asperity Contacts ◽  
Lubrication Characteristics ◽  
Von Mises

Efficiency and durability are among the top concerns in mechanical design to minimize environmental impact and conserve natural resources while fulfilling performance requirements. Today mechanical systems are more compact, lightweight, and transmit more power than ever before, which imposes great challenges to designers. Under the circumstances, some simplified analyses may no longer be satisfactory, and in-depth studies on mixed lubrication characteristics, taking into account the effects of 3D surface roughness and possible plastic deformation, are certainly needed. In this paper, the recently developed plasto-elastohydrodynamic lubrication (PEHL) model is employed, and numerous cases with both sinusoidal waviness and real machined roughness are analyzed. It is observed that plastic deformation may occur due to localized high pressure peaks caused by the rough surface asperity contacts, even though the external load is still considerably below the critical load determined at the onset of plastic deformation in the corresponding smooth surface contact. It is also found, based on a series of cases analyzed, that the roughness height, wavelength, material hardening property, and operating conditions may all have significant influences on the PEHL performance, subsurface von Mises stress field, residual stresses, and plastic strains. Generally, the presence of plastic deformation may significantly reduce some of the pressure spikes and peak values of subsurface stresses and make the load support more evenly distributed among all the rough surface asperities in contact.

A Parametric Study on Fatigue Life for Mixed Elastohydrodynamic Lubrication Point Contacts

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Xiao-Liang Yan ◽  
Xiao-Li Wang ◽  
Yu-Yan Zhang
Keyword(s):  
Shear Stress ◽  
Fatigue Life ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Point Contacts ◽  
Newtonian Flow ◽  
Lubrication Regimes ◽  
Close Relationship ◽  
Lubrication Characteristics ◽  
Effect Of Surface

The lubrication characteristics and fatigue life are numerically analyzed under full film and mixed lubrication regimes, in which the three-dimensional sinusoidal surfaces with changeable wavelengths in x and y directions are used, the geometry changes of the contact areas are described by the various ellipticity, and the non-Newtonian flow of lubricant is described by the sinh-law rheology model. The results show that the influences of characteristic shear stress, wavelength ratio, and ellipticity on lubrication characteristics and fatigue life are remarkable. The effect of surface topography on lubrication characteristics has a close relationship with speed. Increasing the ellipticity and decreasing wavelength ratio and characteristic shear stress can prolong the fatigue life.

Gun Barrel Refurbishing Using a Shrink-Fitted Autofrettaged Liner

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
J. Perry ◽  
M. Perl
Keyword(s):  
Cross Sections ◽  
Cost Effective ◽  
Von Mises Stress ◽  
Maximum Pressure ◽  
Internal Diameter ◽  
Original Performance ◽  
Gun Barrel ◽  
Von Mises ◽  
Von Mises Stresses ◽  
The Cost

During the firing of guns, the barrel undergoes two major damaging processes: wear of its inner surface and internal cracking. Barrel's are condemned based on either the increase of their internal diameter due to wear or the severity of their internal cracking. The cost of replacing such a damaged gun barrel runs in the tenth of thousands of U.S.$. Therefore, cost effective methods are sought for restoring such gun barrels. In the present analysis, a new method is proposed for refurbishing vintage gun barrels by machining their inner damaged layer and replacing it by an intact, autofrettaged, shrink-fit liner that will restore the barrel to its original performance. The design of the shrink-fitted liner is based on two design principles. First, the von-Mises residual stress distribution through the thickness of the barrel at each of its cross sections along the inserted liner should be at least equal in magnitude to von Mises stress, which prevailed in the original barrel. Second, once the maximum pressure is applied to the compound barrel, the von-Mises stresses at the inner surfaces of the liner machined barrel should be equal to their respective yield stresses. The preliminary results demonstrate the ability of this process to mend such barrels and bringing them back to their initial safe maximum pressure (SMP) and their intact conditions, rather than condemn them. Furthermore, from the authors' experience, based on a preliminary rough estimate, such an alternative seems to be cost effective.

Poisson Ratio Effects on the Von Mises and Maximum Shear Stresses in Cylindrical Contacts

2005 ◽  
Author(s):  
Itzhak Green
Keyword(s):  
Shear Stress ◽  
Poisson Ratio ◽  
Unit Length ◽  
Maximum Shear Stress ◽  
Critical Force ◽  
Von Mises Stress ◽  
Maximum Pressure ◽  
Shear Stresses ◽  
Wide Range ◽  
Von Mises

This work determines the location of the greatest elastic distress in cylindrical contacts based upon the distortion energy and the maximum shear stress theories. The ratios between the maximum pressure, the von Mises stress, and the maximum shear stress are determined and fitted by empirical formulations for a wide range of Poisson ratios, which represent material compressibility. Some similarities exist between cylindrical and spherical contacts, where for many metallic materials the maximum von Mises or shear stresses emerge beneath the surface. However, if any of the bodies in contact is excessively compressible the maximum von Mises stress appears at the surface. That transitional Poisson ratio is found. The critical force per unit length that causes yielding onset, along with its corresponding interference and half-width contact are derived.

Fatigue Life Analysis of the Stabilizer Anti-Roll Bar Using ANSYS

2011 ◽  
Vol 383-390 ◽  
pp. 5894-5898 ◽  
Author(s):  
Su Hong Liu ◽  
Fang Li
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Fatigue Life ◽  
Parametric Model ◽  
Von Mises Stress ◽  
Endurance Test ◽  
Finite Element Technology ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Von Mises

The stabilizer anti-roll bar can prevent the vehicle from rollover, so it is important to get the mechanical properties of it. To achieve it, the finite element technology is chosen and the parametric model was built in the first place. The von Mises stress distribution, reliability and the sensitivity were obtained after being analyzed respectively. Based on these, the fatigue life was estimated finally. The fatigue analysis results were contrasted with the life requirements of stabilizer bar’s endurance test.

scholarly journals STUDI NUMERIK UMUR KELELAHAN (FATIGUE LIFE) PADA PROPELLER KAPAL PENANGKAP IKAN DENGAN KAPASITAS MESIN 24 HP

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Rizqi Ilmal Yaqin ◽  
Angger Bagus Prasetiyo ◽  
Pritiansyah Pritiansyah ◽  
Muhammad Haritsah Amrullah ◽  
Binsar Maruli Tua Pakpahan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Rapid Development ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Fishing Boat ◽  
Finite Element Analysis Simulation ◽  
Von Mises ◽  
Model Affect

Propeller is part of a key component in fishing boat propulsion. Propeller can provide momentum to the fluid which can be a thrust on the ship. However, The failure of the propeller found prematurely. The failure of the propeller maybe because of overload on the propeller model so the fatigue life of the propeller becomes low. On the other hand, the rapid development of technology can simulate a design model to look for failures that occur. Finite Element Analysis is one of the designer solutions to determine the age of failure of a model and failure-prone areas in a model. This study uses propeller model data from fishing boat with engine 24HP in Dumai City TPI that always fail prematurely. The material used is copper alloy. While the drawing model uses Autodesk Inventor and Finite Element Analysis simulation using ANSYS R17.2 software with the number of model nodes is 51108 and the number of elements of the model is 26268. The results obtained from this study are Von Mises stress on the simulation model that is equal to 613.33 MPa to 0.01164 MPa. While the deformation value due to the effect of loading on the model is 5,3657 mm to 0 mm. These results affect the age of fatigue (fatigue life) on the model with the highest value 109 and the lowest 0. The results of the fatigue life value on the model affect the results of the level of damage and the safety number of the model with successive values of 1032 to 1 and 15 to 0.32446. The conclusion of the result is the propeller will fail prematurely.

scholarly journals Influence of the Realistic Artery Geometry Parameters on a Coronary Stent Fatigue Life

2019 ◽  
Vol 16 (03) ◽  
pp. 1842006 ◽  
Author(s):  
Xinyang Cui ◽  
Qingshuai Ren ◽  
Gaoyang Li ◽  
Zihao Li ◽  
Aike Qiao
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Safety Factor ◽  
Geometric Model ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Goodman Diagram ◽  
Von Mises ◽  
Geometry Parameter ◽  
Artery Geometry

The stents’ adaptability and safety in realistic and idealized stenotic coronary model were compared to investigate the influence of artery geometry parameter on stent fatigue life. The stents’ fatigue resistance ability was calculated using Goodman diagram, and the cycle to failure, the fatigue life, and the fatigue safety factor (FSF) were analyzed. Although the peak top of the von Mises stress was located at the bending area of crowns, the stress distributions were different in the two models. Considering the safety and accuracy, it is necessary to use a realistic geometric model to calculate the stent fatigue performance.

Block Cycle Fatigue Life Simulation and Correlation With Test for an Automotive Hood Latch-Supporting Component

2002 ◽  
Author(s):  
Gene Y. Liao
Keyword(s):  
Fatigue Life ◽  
Analysis Procedure ◽  
Von Mises Stress ◽  
Cycle Fatigue ◽  
Durability Analysis ◽  
Von Mises ◽  
Critical Regions ◽  
High Possibility ◽  
Industrial Part

This paper describes the durability analysis procedure and fatigue life simulation of an automotive hood latch-supporting component under block cycle loads. The first step is to apply linear stress analysis to identify the regions with high possibility of failure. The bent cove section of the latch support and the upper bolt-edge on a tie bar connecting to the latch support are determined as the critical regions. The strain-life/signed von Mises stress approach is then used to perform the fatigue analysis at these critical regions. The predicted fatigue life is about 3 times of the experimental one. However, the experiment shows that a crack appears exactly at the bent cove section of the latch support as simulation predicted. This project also serves as a case study to the students in predicting fatigue failure of a real industrial part.

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