Bending fatigue design of case-hardened gears based on test specimens

2017 ◽  
Vol 232 (11) ◽  
pp. 1953-1969 ◽  
Author(s):  
Giovanni Meneghetti ◽  
Carlo Dengo ◽  
Fulvio Lo Conte
Keyword(s):  
Experimental Data ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Sensitivity Factor ◽  
Reference Test ◽  
Iso Standard ◽  
Bending Fatigue ◽  
Notched Specimens ◽  
Fatigue Design ◽  
Gear Steel

Different design methods against bending fatigue are reported in ISO 6336 standard. The standard suggests primarily the method based on reference test gears and provides the relevant fatigue curves. Additionally, the standard suggests the use of specimens (instead of gears) to generate the reference fatigue curves, but it also advices that specimen-based methods can be used when gears are not available and that specimens are particularly useful for comparing fatigue performances of gear materials relative to one another. The purpose of the present paper is to evaluate the accuracy of the specimen-based methods mentioned in the ISO standard when applied to design gears against bending fatigue. Experimental data were generated by means of pulsator fatigue tests on case-hardened gears used in off-highway vehicles. Afterwards, experimental results were compared with theoretical estimations according to the approaches based on reference test gears (as suggested by the ISO standard) and test specimens. Concerning the latter approach, the relevant fatigue design curves were generated by testing smooth as well as notched specimens made of the same case-hardened gear steel. It was found that the specimens-based methods are as accurate as the reference gears-based method, provided that the material notch sensitivity factor is properly calibrated on the experimental results obtained from specimens.

scholarly journals Pitting and Bending Fatigue Evaluations of a New Case-Carburized Gear Steel

2007 ◽  
Author(s):  
Timothy Krantz ◽  
Brian Tufts
Keyword(s):  
Power Density ◽  
Fatigue Testing ◽  
Surface Hardness ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Surface Fatigue ◽  
Gear Steel ◽  
Single Tooth ◽  
Carburized Gear ◽  
Gear Steels

The power density of a gearbox is an important consideration for many applications and is especially important for gearboxes used on aircraft. One approach to improving power density of gearing is to improve the steel properties by design of the alloy. The alloy tested in this work was designed to be case-carburized with surface hardness of Rockwell C66 after hardening. Test gear performance was evaluated using surface fatigue tests and single-tooth bending fatigue tests. The performance of gears made from the new alloy was compared to the performance of gears made from two alloys currently used for aviation gearing. The new alloy exhibited significantly better performance in surface fatigue testing, demonstrating the value of the improved properties in the case layer. However, the alloy exhibited lesser performance in single-tooth bending fatigue testing. The fracture toughness of the tested gears was insufficient for use in aircraft applications as judged by the behavior exhibited during the single tooth bending tests. This study quantified the performance of the new alloy and has provided guidance for the design and development of next generation gear steels.

scholarly journals Cyclic Tests of Smooth and Notched Specimens Subjected to Bending and Torsion Taking into Account the Effect of Mean Stress

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2141 ◽  
Author(s):  
Roland Pawliczek ◽  
Dariusz Rozumek
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Regression Equations ◽  
Allowable Stress ◽  
Cyclic Tests ◽  
Mean Values ◽  
Notched Specimens ◽  
Fatigue Characteristics

The paper contains the results of fatigue tests of smooth and notched specimens made of 10HNAP (S355J2G1W) subjected to proportional cyclic loading with use of mean values stress. The results obtained for specimens under bending, torsion and one combination of bending with torsion for four mean values have been compared. The experimental data have been collected in the tables and shown in the figures with use of various σa(τa)-N fatigue characteristics for which parameters of the regression equations have been determined. The influence of average values on the allowable stress amplitudes and amplitude of moments at the level close to the fatigue limit depending on the angle α determining loading combination and the average stress is also shown. The greatest effect of the notch on fatigue life compared to smooth specimens is observed at symmetrical loads. At unsymmetrical loads with non-zero mean stress, this effect clearly weakens or disappears.

scholarly journals Experiment and Finite Analysis on Resonant Bending Fatigue of Marine Risers

2015 ◽  
Vol 9 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Fang Xiaoming ◽  
Yan Zhichao ◽  
Wang Liquan ◽  
Huang Yuxuan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fatigue Test ◽  
Element Model ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Oil And Gas Development ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
The Finite Element Model

Riser system is a key equipment for offshore oil and gas development. When conducting riser design, fatigue failure mode is the chief one among the many failure modes which should be taken into account. To assess the fatigue performance of riser accurately, it is necessary to conduct fatigue tests. Resonant bending fatigue test is one effective method for fatigue tests of risers. In this paper, the principle of resonant bending fatigue test and test procedures are presented firstly, and then a finite element model using ABAQUS is created to simulate the resonant bending fatigue test, and the results from the finite element model are compared with the experimental results. The good agreements between the FEM results and experimental results verify the accuracy of the finite element model in this paper.

Modification of the Equation for Description of Wöhler's Curves

2010 ◽  
Vol 27 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Sylwester Kłysz ◽  
Janusz Lisiecki ◽  
Tomasz Bąkowski
Keyword(s):  
Experimental Data ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Fatigue Threshold ◽  
Cycle Fatigue ◽  
Exponential Equation ◽  
The Way

Modification of the Equation for Description of Wöhler's Curves The paper presents the way to modify the equation σ = f(2Nf) in order to improve the fit of experimental results from High Cycle Fatigue tests. In particular, the study deals with introduction of the 5-parameter exponential equation that enables better fit of the full Wöhler's curve to experimental data within the range of stress at the level of fatigue threshold as well as approximation to the quasi-static range and Low Cycle Fatigue tests for the highest stress values. It is illustrated how individual parameters affect the procedure and possibility to match the aforementioned equation to experimental data.

Fatigue Design of Leaf Spring Based on Proving Ground

2004 ◽  
Vol 261-263 ◽  
pp. 1295-1300
Author(s):  
Il Seon Sohn ◽  
Dong Ho Bae ◽  
Won Seok Jung ◽  
S.J. Park
Keyword(s):  
Design Method ◽  
Maximum Load ◽  
Fatigue Tests ◽  
Design Criterion ◽  
Bending Test ◽  
Leaf Spring ◽  
Bending Fatigue ◽  
The Road ◽  
Fatigue Design ◽  
Test Result

The suspension system of vehicle is directly influenced to ride and handling. Therefore, suspension part should have enough endurance during its lifetime to protect passenger. Spring is one of major suspension part of vehicle. Thus, in this paper, a fatigue design method for leaf spring based on proving ground response was proposed. At first, stress and displacement of leaf spring are measured through the proving ground test. And next, the maximum load acting on leaf spring assembly under driving condition was defined from the road load response. On the base of these results, fatigue tests for leaf spring assembly and 3-point bending fatigue tests for material of leaf spring were carried out. From the above, the maximum load-fatigue life relation of leaf spring material and assembly was defined, and 3-point bending test result has good agreement with leaf spring assembly fatigue test result. Thus, it is expect that economical fatigue design criterion for leaf spring assembly can be determined from fatigue data of simple smooth specimen by 3 point bending fatigue tests.

Effect of Moisture Absorption on the Bending Fatigue Performance of Carbon/Epoxy Laminates

2011 ◽  
Vol 415-417 ◽  
pp. 2308-2311
Author(s):  
A Ying Zhang ◽  
Di Hong Li ◽  
Cheng Li Liang ◽  
Jiu Si Jia ◽  
Dong Xing Zhang
Keyword(s):  
Moisture Content ◽  
Composite Laminates ◽  
Moisture Absorption ◽  
Threshold Level ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Fatigue Properties ◽  
Material Strength ◽  
Bending Fatigue ◽  
Effect Of Moisture

This study investigates the effect of moisture content on the bending fatigue properties of T300/914 composite laminates immersed in water for 7 days and 14 days. Displacement-controlled three-point bending fatigue tests were conducted on specimens. After 40,000 cycles the fatigue test was stopped and the properties were measured on the tested specimens. Reduction in material strength was found to depend on the level of moisture content. Experimental results reveal that the moisture content in the laminates increased with immersion time and that moisture absorption accelerated damage propagation in the composite. Hygrothermal ageing lowered the threshold level for the onset of fatigue. The experimental results were further validated by the supportive micrographs that illustrate different moisture content and their morphology before and after moisture absorption.

Four Point Bending Fatigue Tests of Forged Ti 6Al 4V

2009 ◽  
Vol 51 (9) ◽  
pp. 580-586 ◽  
Author(s):  
Bernd Oberwinkler ◽  
Martin Riedler ◽  
Heinz Leitner ◽  
Ataollah Javidi
Keyword(s):  
Fatigue Tests ◽  
Bending Fatigue ◽  
Four Point Bending

Bending fatigue of single-wall and double-wall corrugated paperboards under sinusoidal and random loads

2021 ◽  
pp. 109963622110204
Author(s):  
Zhi-Wei Wang ◽  
Yang-Zhou Lai ◽  
Li-Jun Wang
Keyword(s):  
Energy Dissipation ◽  
Fatigue Failure ◽  
Fatigue Tests ◽  
Stiffness Degradation ◽  
Random Load ◽  
Bending Fatigue ◽  
Random Loads ◽  
Vibration Fatigue ◽  
Sinusoidal Load ◽  
Double Wall

The bending fatigue tests of single-wall and double-wall corrugated paperboards were conducted to obtain the εrms– N curves under sinusoidal and random loads in this paper. The εrms– N equation of corrugated paperboard can be described by modified Coffin–Manson model considering the effect of mean stress. Four independent fatigue parameters are obtained for single-wall and double-wall corrugated paperboards. The εrms– N curve under random load moves left and rotates clockwise compared with that under sinusoidal load. The fatigue life under random load is much less than that under sinusoidal load, and the fatigue design of corrugated box should be based on the fatigue result under random load. The stiffness degradation and energy dissipation of double-wall corrugated paperboard before approaching fatigue failure are very different from that of single-wall one. For double-wall corrugated paperboard, two turning points occur in the stiffness degradation, and fluctuation occurs in the energy dissipation. Different from metal materials, the bending fatigue failure of corrugated paperboard is a process of wrinkle forming, spreading, and folding. The results obtained have practical values for the design of vibration fatigue of corrugated box.

Convective Losses From Cavity Solar Receivers—Comparisons Between Analytical Predictions and Experimental Results

1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing
Keyword(s):  
Experimental Data ◽  
Experimental Evidence ◽  
Analytical Model ◽  
Excellent Agreement ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Refined Model ◽  
Wall Area

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.

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