Analyses of Contact Pressure and Stress Amplitude Effects on Fretting Fatigue Life

2000 ◽  
Vol 123 (1) ◽  
pp. 85-93 ◽  
Author(s):  
K. Iyer ◽  
S. Mall
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Contact Pressure ◽  
Stress Amplitude ◽  
Normal Load ◽  
Contact Region ◽  
Local Stress ◽  
Fretting Fatigue ◽  
Element Analysis ◽  
Stress Ratios

Elastic-plastic finite element analyses of a cylinder-on-plate configuration, studied experimentally, were performed to provide an explanation for the decrease in fretting fatigue life with increasing contact pressure. Three values of normal load, namely 1338 N, 2230 N, and 3567 N, and three stress ratios (0.1, 0.5, and 0.7) were considered. Based on a previously determined dependency between contact pressure and friction coefficient, the effect of coefficient of friction was also evaluated. The deformation remained elastic under all conditions examined. Cyclic, interfacial stresses, and slips were analyzed in detail. The amplification of remotely applied cyclic stress in the contact region is shown to provide a rationale for the effect of contact pressure and stress amplitude on life. Comparisons with previous experiments indicate that the local stress range computed from finite element analysis may be sufficient for predicting fretting fatigue life. Further, the results suggest that the slip amplitude and shear traction may be neglected for this purpose.

Finite Element Analysis for Demolding Process in Thermal Imprint Lithography

2007 ◽  
Author(s):  
Zhichao Song ◽  
Jaejong Lee ◽  
Sunggook Park
Keyword(s):  
Finite Element ◽  
Contact Region ◽  
Substrate Surface ◽  
Mold Insert ◽  
Local Stress ◽  
Imprint Lithography ◽  
Structural Failure ◽  
The Finite Element Method ◽  
Element Analysis ◽  
The Ideal

In thermal imprint lithography, most of the imprint failures occur during demolding, a process to separate the mold insert from the substrate after conformal molding. The success of demolding is determined by the stress generated in the resist with respect to the yield stress of the resist. In this paper we simulated the demolding process in thermal imprint lithography using the finite element method to study the stress distribution and deformation in poly(methyl methacrylate) (PMMA) resist during demolding. During demolding, the stress concentrates both at the transition corner zone between the residual layer and the replicated pattern, and close to the contact region with the moving stamp. As demolding proceeds, the highest local stress for both locations shows two maximums, indicating that a structural failure may occur not only when demolding starts, but also immediately before demolding ends. The structural failure at the second maximum becomes dominant as the angular offset from the ideal normal demolding to the substrate surface increases or for the structures located far away from the symmetric centerline. In addition, we will discuss the influence of other process and geometry parameters, including demolding rate and stamp aspect ratio.

Fretting fatigue behavior and failure characteristics of 35CrMoA steel under elliptical loading path

2021 ◽  
Vol 73 (6) ◽  
pp. 922-928
Author(s):  
Ziao Huang ◽  
Xiaoshan Liu ◽  
Guoqiu He ◽  
Zhiqiang Zhou ◽  
Bin Ge ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Contact Pressure ◽  
Wear Debris ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Cyclic Stress ◽  
Loading Path ◽  
Fatigue Wear ◽  
Content Type

Purpose This study aims to understand the multiaxial fretting fatigue, wear and fracture characteristics of 35CrMoA steel under the elliptical loading path. Design/methodology/approach By keeping the contact pressure and torsional shear cyclic stress amplitude unchanged; the axial cyclic stress amplitude varied from 650 MPa to 850 MPa. The fretting fatigue test was carried out on MTS809 testing machine, and the axial cyclic strain response and fatigue life of the material were analyzed. The fretting zone and fracture surface morphology were observed by scanning electron microscope. The composition of wear debris was detected by energy dispersive X-ray spectrometer. Findings In this study, with the increase of axial stress amplitude, 35CrMoA steel will be continuously softened, and the cyclic softening degree increases. The fretting fatigue life decreases unevenly. The fretting scars in the stick region are elongated in the axial direction. The area of fracture crack propagation zone decreases. In addition, the results indicate that wear debris in the slip region is spherical and has higher oxygen content. Originality/value There were few literatures about the multiaxial fretting fatigue behavior of 35CrMoA steel, and most scholars focused on the contact pressure. This paper reveals the effect of axial cyclic stress on fretting fatigue and wear of 35CrMoA steel under the elliptical loading path.

Effect of Contact Pressure and Cyclic Stress Amplitude on Fretting Fatigue of 45-Carbon Steel

2007 ◽  
Vol 353-358 ◽  
pp. 134-137
Author(s):  
Wei Ming Sun ◽  
Shui Sheng Chen ◽  
Li Qun Tu
Keyword(s):  
Fatigue Life ◽  
Carbon Steel ◽  
Contact Pressure ◽  
Main Crack ◽  
Stress Amplitude ◽  
Fretting Fatigue ◽  
Cyclic Stress ◽  
Outer Edge ◽  
Middle Portion ◽  
Contact Pressures

The effect of contact pressure on fretting fatigue in quenched and tempered 45-carbon steel is studied. With an increase in contact pressure, fretting fatigue life is decreased quickly at low contact pressures; however it almost unchanged at high contact pressures. With an increase in cyclic stress amplitude, fretting fatigue life decreased. In the test, concavity is formed at the fretted area accompanying wear. The main crack is initiated at the outer edge corner of the concavity at high contact pressures, and initiated at the middle portion of the fretted area at low contact pressures.

Prediction of Fretting Fatigue Life of Aluminum Alloy LY12CZ

2010 ◽  
Vol 146-147 ◽  
pp. 252-256
Author(s):  
Moo Sheng Yang ◽  
Yue Liang Chen ◽  
Yu Quan Bi ◽  
Wen Hao Jiang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Influence Factor ◽  
Stress Amplitude ◽  
Normal Load ◽  
Fretting Fatigue ◽  
Damage Parameter ◽  
Finite Element Software ◽  
Increase With Increase ◽  
Bulk Stress

Stress in the interface of contacts was calculated applying finite element software/ABAQUS, with which the Ruiz fretting damage parameter was obtained and the location for crack formation was found. A new model for predicting fretting fatigue life has been presented based on friction work. The rationality and effectiveness of the model were validated according to the contrast of experiment life and predicting life. At last influence factor on fretting fatigue life of aerial aluminum alloy LY12CZ was investigated with the model. The results revealed that fretting fatigue life decreased monotonously with the increasing of normal load and then became constant at higher pressures. At low normal load, fretting fatigue life was found to increase with increase in the pad radius. At high normal load, however, the fretting fatigue life remained almost unchanged with changes in the fretting pad radius. The bulk stress amplitude had the dominant effect on fretting fatigue life. The fretting fatigue life diminished as the bulk stress amplitude increased.

Numerical Fatigue Life Evaluation With Experimental Results for Type III Accumulators

2018 ◽  
Author(s):  
Sang-Won Kim ◽  
Nobuhiro Yoshikawa ◽  
Hiroshi Kobayashi ◽  
Toshiro Fujisawa ◽  
Takeru Sano
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Life Prediction ◽  
Stress Amplitude ◽  
Element Model ◽  
Fatigue Life Prediction ◽  
Element Analysis ◽  
Type Iii ◽  
Principal Axes ◽  
Pressure Cycle

Composite Reinforced Accumulator (CRA) is widely used in hydrogen stations. A high-cost pressure cycle test is mandatory to ensure the safety of accumulator in present regulations. To reduce the high cost, the aim is to develop a methodology of numerical fatigue life prediction of CRA with results of pressure cycle tests. An axisymmetric finite element model for the Type III accumulator is created and actual loading process including autofrettage pressure is simulated. Stress amplitude caused by pressure cycle is evaluated based on the instructions in KD-3 of ASME BPVC VIII 3-2015. By comparing stress amplitude distributions with the leak positions after the pressure cycle test, and plotting the results in the design fatigue curve, it could be shown that fatigue life prediction of Type III accumulator can be done by precise finite element analysis of the liner including dome part, where the principal axes of stress change in pressure cycle.

Effects of Shot-Peening on Fretting-Fatigue Behavior of Ti-6Al-4V

2002 ◽  
Vol 124 (2) ◽  
pp. 222-228 ◽  
Author(s):  
S. A. Namjoshi ◽  
V. K. Jain ◽  
S. Mall
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Contact Region ◽  
Fretting Fatigue ◽  
Initiation Site ◽  
Fatigue Tests ◽  
Residual Tensile Stress ◽  
X Ray Diffraction ◽  
Element Analysis

The effects of shot-peening on the fretting fatigue behavior of titanium alloy, Ti-6Al-4V were investigated. Specimens were shot-peened as per AMS 2432 standard. X-ray diffraction analysis measured a maximum compressive stress of 800 MPa at the specimen surface, which reduced to zero at a depth of 188 μm. The compensatory residual tensile stress in the specimen was estimated using a curve fitting technique, the maximum value of which was found to be 260 MPa at a depth of 255 μm. Fretting fatigue tests were conducted at room temperature at a cyclic frequency of 200 Hz. Scanning electron microscopy of the shot-peened fretting fatigue specimens showed that the crack initiated at a point below the contact surface, the depth of which was in the range of 200–300 μm. Finite element analysis of the fretting fatigue specimens was also conducted. Fatigue life diagrams were established for the fretting fatigue specimens with and without shot-peening, and were compared to those under the plain fatigue condition, i.e. without fretting. Shot-peening improved the fretting fatigue life of Ti-6Al-4V; furthermore, it moved the crack initiation site from the fretting contact region to a region inside the specimen. Moreover, stress analysis showed that the fatigue failure of shot-peened specimens was caused by the compensatory tensile residual stress.

Finite Element Modeling for Steel Cord Analysis in Radial Tires

2013 ◽  
Vol 41 (1) ◽  
pp. 60-79 ◽  
Author(s):  
Wei Yintao ◽  
Luo Yiwen ◽  
Miao Yiming ◽  
Chai Delong ◽  
Feng Xijin
Keyword(s):  
Finite Element ◽  
High Efficiency ◽  
Force Measurement ◽  
Three Dimensional ◽  
Local Stress ◽  
Tension Force ◽  
Center Line ◽  
Element Analysis ◽  
Design Variables ◽  
Steel Cord

ABSTRACT: This article focuses on steel cord deformation and force investigation within heavy-duty radial tires. Typical bending deformation and tension force distributions of steel reinforcement within a truck bus radial (TBR) tire have been obtained, and they provide useful input for the local scale modeling of the steel cord. The three-dimensional carpet plots of the cord force distribution within a TBR tire are presented. The carcass-bending curvature is derived from the deformation of the carcass center line. A high-efficiency modeling approach for layered multistrand cord structures has been developed that uses cord design variables such as lay angle, lay length, and radius of the strand center line as input. Several types of steel cord have been modeled using the developed method as an example. The pure tension for two cords and the combined tension bending under various loading conditions relevant to tire deformation have been simulated by a finite element analysis (FEA). Good agreement has been found between experimental and FEA-determined tension force-displacement curves, and the characteristic structural and plastic deformation phases have been revealed by the FE simulation. Furthermore, some interesting local stress and deformation patterns under combined tension and bending are found that have not been previously reported. In addition, an experimental cord force measurement approach is included in this article.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

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