The Effect of Density on the Bending Fatigue of Powdered Metal Gears

2007 ◽  
Author(s):  
David A. Alven ◽  
Peter G. Imbrogno
Keyword(s):  
Significant Influence ◽  
Fatigue Testing ◽  
Fatigue Properties ◽  
Powder Metal ◽  
Bending Fatigue ◽  
Powdered Metal ◽  
Single Tooth

The bending fatigue properties of powder metal (P/M) gears as a function of density were investigated. SAE-AISI 4600 based steel gears were manufactured using various powdered metal processes. The processes used were press and sinter, double press and double sinter, surface densify, and powder forge (P/F). The resulting gears were then subjected to single tooth bending fatigue testing and compared with 4600 based wrought gears. It was found that the density of the P/M part had a significant influence on the bending fatigue properties. When compared to the wrought material, a P/M gear of equivalent density was found to have similar bending fatigue properties.

Fatigue of Metal Free Reed due to Self-Excited Oscillation

2008 ◽  
Vol 33-37 ◽  
pp. 267-272
Author(s):  
Yoshinobu Shimamura ◽  
Keiichiro Tohgo ◽  
Hiroyasu Araki ◽  
Yosuke Mizuno ◽  
Shoji Kawaguchi ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
The Self ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Metal Free ◽  
Mass Damper ◽  
Excited Oscillation ◽  
Analytical Research ◽  
Fatigue Characteristics ◽  
Good Agreement

Metal free reeds are used for musical instruments like harmonica. Free reeds are small, thin cantilevers, and oscillate by blowing air. It is reported that free reeds break due to fatigue during play. In order to elongate the life of free reeds, the fatigue properties should be investigated and a motion analysis method should be developed. The experimental and analytical research on metal free reed, however, has been rarely reported. In this study, two types of fatigue testing machines were developed to obtain basic fatigue characteristics. The fatigue testing machines are designed for bending fatigue of actual free reeds whose thickness is less than 400 μm. An S-N diagram is successfully obtained up to 107 cycles by using the developed fatigue testing machines. The fracture surfaces of fatigued specimens are in good agreement with those of free reeds failed in use. Then, an analytical method for the self-excited oscillation of free reeds was developed based on a mass-damper-spring model. The proposed method can take account for the shape of free reed. The self-excited oscillation of free reeds with different shape are analyzed and in good agreement with experimental results.

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.

Contact and bending fatigue behaviour of austempered ductile iron gears

2017 ◽  
Vol 232 (6) ◽  
pp. 998-1008 ◽  
Author(s):  
Carlo Gorla ◽  
Edoardo Conrado ◽  
Francesco Rosa ◽  
Franco Concli
Keyword(s):  
Ductile Iron ◽  
Contact Fatigue ◽  
Research Programme ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Austempered Ductile Iron ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Metallurgical Analysis ◽  
Single Tooth

In the present paper a research programme aimed at investigating both the bending and contact fatigue properties of an austempered ductile iron applied to gears is presented, in order to determine reliable values of the limits, which take into account the influence of the production process, to be applied in the design of gearboxes. The bending fatigue tests are performed according to the single tooth fatigue approach and the pitting tests are performed with a back-to-back rig. Metallurgical analysis is performed on the failed specimens, in order to understand the origin and the propagation of the failures and to appreciate the influence of the micro-structure on the performances obtained.

Finite Fatigue Life Distributions of SAE 1008 Subjected to Various Load-Time Histories

1980 ◽  
Vol 102 (1) ◽  
pp. 135-140 ◽  
Author(s):  
H. A. ElMaraghy ◽  
J. N. Siddall
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Narrow Band ◽  
Fatigue Properties ◽  
Load History ◽  
Random Load ◽  
Bending Fatigue ◽  
Theoretical Predictions ◽  
Time Histories ◽  
Life Distributions

The probabilistic fatigue properties of SAE 1008 steel were determined experimentally. A flexural bending fatigue testing program was carried out consisting of: (a) constant strain amplitude, (b) blocks of Hi-Lo and Lo-Hi-Lo strain amplitudes, and (c) narrow band random load history. Fatigue life of 30-45 specimens in each program were recorded and used to construct distributions of fatigue life. A computer simulation technique was used to predict these distributions. Experimental results and theoretical predictions are both presented for comparison.

Influence of the Filler Root Surface Treatment on Bending Fatigue Test Results of the Hardened Gears

2013 ◽  
Vol 586 ◽  
pp. 154-157 ◽  
Author(s):  
Petr Jonšta ◽  
Petr Maršálek ◽  
Jiří Havlík ◽  
Zdenĕk Jonšta
Keyword(s):  
Surface Treatment ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Reference Conditions ◽  
Hardness Measurement ◽  
Root Surface ◽  
Fatigue Properties ◽  
Surface Finishing ◽  
Design Parameters ◽  
Bending Fatigue

This article deals with testing of fatigue properties of hardened gears at bending. These tests are defined by the standard ISO 6336 - method B, when testing is carried out under reference conditions close to the real operation. This type of testing may be helpful to evaluate the influence of new materials, design parameters, production technology, or the effects of surface finishing. The first part of this article deals with the theory of fatigue testing methodology using modified stair-case method and characteristics of the testing machine. The second part of the paper is devoted to the characteristics of the experimental material and the results achieved. The case hardened steel gears alloyed by Cr-Ni-Mo were selected for the experiment. Hardened gears were subjected to local hardness measurement and subsequently the bending fatigue tests were performed. Ruptured samples were analyzed using a scanning electron microscope. The local bending stress was determined using the modified computational model based on the ISO 6336 standard methodology. The focus of this work consisted in evaluation of the influence of the filler root surface treatment on fatigue limit at bending on the basis of the realized experiments and their confrontation with the equivalents specified in the standards ISO 6336 and ČSN 01 4686.

scholarly journals Effect of Nonmetallic Inclusions on Fatigue Properties of Superelastic Ti-Ni Fine Wire

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 999 ◽  
Author(s):  
Fumiyoshi Yamashita ◽  
Yasunori Ide ◽  
Suguru Kato ◽  
Kyosuke Ueda ◽  
Takayuki Narushima ◽  
...  
Keyword(s):  
Nonmetallic Inclusions ◽  
Fatigue Testing ◽  
Fatigue Properties ◽  
Titanium Oxides ◽  
Bending Fatigue ◽  
Fine Wire ◽  
Ni Alloy ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Defect Morphology

This study investigated the effects of the types and length of nonmetallic inclusions on fatigue properties in rotating bending fatigue testing of Ti-Ni alloy fine wire. It was fabricated to include titanium carbides Ti(C,O) and titanium oxides Ti4Ni2Ox as either single phases or a mixture of both phases as nonmetallic inclusions in Ti-Ni alloy. The fatigue strength of Ti-Ni alloy depended on the number of nonmetallic inclusions of a length of ≥2 μm. Compared with Ti(C,O), Ti4Ni2Ox is coarse. It also exhibited a trend of readily forming particles and void assemblies, which are a defect morphology that originates from nonmetallic inclusions and readily act as crack origins of fatigue fractures.

Study on the Bending Fatigue Properties of Nomex Fiber

2014 ◽  
Vol 1048 ◽  
pp. 62-65
Author(s):  
Guang Ming Cai ◽  
Xin Wang
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Testing ◽  
Ccd Camera ◽  
Fracture Morphology ◽  
Fatigue Properties ◽  
Bending Angle ◽  
Bending Fatigue ◽  
Different Temperatures ◽  
Bending Fatigue Strength

In this paper, we reported a bending fatigue testing apparatus which can test the bending fatigue properties of single Nomex fiber by setting the pretension, bending angle and temperature. The S-N and θ-N curves indicated that the pre-tension and bending angle had great influences on the bending fatigue life of Nomex fiber. A CCD camera was utilized to allow observation of the bending fatigue fracture morphology of fiber. It showed the fracture mechanism of Nomex fibers. The bending fatigue life of Nomex fiber was tested at different temperatures to show that its bending fatigue strength is strongly influenced by the temperature.

Bending Fatigue Damage Behavior of Annealed Polycrystalline Cu Foil

2019 ◽  
Vol 971 ◽  
pp. 53-58
Author(s):  
Ming Wang ◽  
Xu Zhang ◽  
Li Li Cheng ◽  
Qiang Zhang
Keyword(s):  
Fatigue Damage ◽  
Fatigue Testing ◽  
Strain Range ◽  
Model Material ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Cu Films ◽  
Final Failure ◽  
Cu Foil ◽  
Micrometer Scale

The metal foils at micrometer scale are applied in micro-electromechanical systems (MEMS) and devices widely, which the mechanical behaviors of them are significantly different from that of bulk materials and thin films constrained by a substrate. In this paper the annealed polycrystalline Cu foil with two thickness (t =100, 150 μm) was applied on the cantilever beam bending fatigue testing as a model material. The fatigue properties and the damage behaviors of the annealed polycrystalline Cu foil at the total strain control was investigated. The results showed that the bending fatigue life of the polycrystalline Cu foil with the grain size (d =9.2 μm) was significantly larger than that of the Cu bulk and thin Cu films with t =3 μm under the same strain range. The fatigue damage formation of the extrusions/intrusions and cracks along grain boundaries on the Cu foil surface caused fatigue fracture and final failure.

A Testing Device for Fatigue Crack Propagation Experiments on Bevel and Face Gears

2003 ◽  
Author(s):  
Mauro Filippini ◽  
Carlo Gorla
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Gear Wheel ◽  
Fatigue Tests ◽  
Testing Device ◽  
Bending Fatigue ◽  
Single Tooth

A testing device for performing single tooth bending fatigue tests on bevel and face gears is presented. Basically, it works as a normal gearbox in which the pinion acts as loading element while the gear wheel is kept fixed to the frame. The entire rig is installed in a servo-hydraulic torsion fatigue testing machine, so that torque amplitudes up 2200 Nm may be applied with convenient loading frequencies. Torque amplitude is measured by connecting the testing rig to the load cell of the testing machine. It’s possible to rotate the gearwheel at fixed positions so that a large number of teeth of the same wheel may be tested. If the tests are performed on teeth weakened by pre cracking, no special pinion is requested. The proposed testing rig may be employed for testing both bevel and face gears, by simply adapting the parts that keep the gearwheel fixed with the frame and by choosing the proper meshing pinion.

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