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

Author(s):  
Mauro Filippini ◽  
Carlo Gorla

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.

2014 ◽  
Vol 891-892 ◽  
pp. 911-916
Author(s):  
Pavel Hutař ◽  
Ivo Kuběna ◽  
Miroslav Šmíd ◽  
Martin Ševčík ◽  
Tomáš Kruml ◽  
...  

The oxide dispersion strengthened (ODS) steels are widely studied as possible candidate material for fission and fusion technology. Due to application of the ODS materials, mainly low cycle fatigue is important. Therefore, small crack initiation and propagation for rather high stress amplitude are in focus. The main aim of the presented work is description of the small fatigue crack propagation for ODS-EUROFER steel. Due to limited quantity of ODS steel special miniaturized cylindrical specimens for fatigue testing were designed. Crack propagation law based on plastic part of J-integral is presented and applied for mentioned material. The resulting fatigue crack propagation rates for ODS-EUROFER steel and EUROFER 97 are compared and discussed.


Author(s):  
Ana Maria Gontijo Figueiredo ◽  
Gabriel de Oliveira Ribeiro ◽  
José Felipe Dias ◽  
Paulo José Modenesi ◽  
Felipe Leonardo Pereira Queiroz ◽  
...  

Author(s):  
Masahito Mochizuki ◽  
Yoshiki Mikami

The effect of transformation-induced microscopic residual stress on fatigue crack propagation behaviour of ferrite-martensite lamellar steel was discussed. Fatigue tests of prestrained and non-prestrained specimens were performed. Inflections and branches at ferrite-martensite boundaries were observed in the non-prestrained specimens. On the other hand, less inflections and branches were found in the prestrained specimens. The experimental results showed that the transformation induced microscopic residual stress has influence on the fatigue crack propagation behaviour. To estimate the microscopic residual stress distribution, a numerical simulation of microscopic residual stress induced by martensitic transformation was performed. The simulation showed that compressive residual stress was generated in martensite layer, and the result agree with the experimental result that inflections and branches were observed at ferrite-martensite boundaries. In addition, the change in the microscopic residual stress distribution by prestraining was also calculated to show the compressive residual stress changed to tensile by prestraining. This also agree with the experimental result of the observation of fatigue crack path.


Author(s):  
Timothy Krantz ◽  
Brian Tufts

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.


2019 ◽  
Vol 149 ◽  
pp. 82-94 ◽  
Author(s):  
Arun Ramanathan Balachandramurthi ◽  
Johan Moverare ◽  
Nikhil Dixit ◽  
Dunyong Deng ◽  
Robert Pederson

2005 ◽  
Vol 297-300 ◽  
pp. 2929-0
Author(s):  
Cheong Cheon Lee ◽  
Akira Shimamoto

In this paper, the TiNi fiber reinforced/PMMA (Poly methyl methacrylate) composite is developed, and its effectiveness of controlling fatigue crack growth is studied. The TiNi fiber reinforced/PMMA composite’s mechanical property enhancement and deformation resistance are also studied. The fatigue behavior and crack propagation are observed with a SEM servo-pulser (fatigue testing instrument with scanning electron microscope) while increasing temperature. As the results, it is confirmed that the fatigue life and resistance are improved. How the shape memory effect and expansion behavior of the matrix caused by temperature increasing affect the fatigue crack propagation control is examined. It is verified that the control of fatigue crack growth is attributed to the compressive stress field in the matrix due to shrinkage of the TiNi fibers above austenitic finishing temperature (Af).


1971 ◽  
Vol 14 (76) ◽  
pp. 1013-1020
Author(s):  
Minoru KAWAMOTO ◽  
Yukihiko IBUKI ◽  
Toshinobu SHIBATA ◽  
Hiroshi ISHIKAWA

2012 ◽  
Vol 600 ◽  
pp. 273-278
Author(s):  
Zong Hong Xie ◽  
Tian Jiao Zhao ◽  
Rui Wu

This study is to investigate the fatigue crack growth behavior of Glare3-3/2 under various stress levels. The Glare3-3/2 specimen consists of three 2024-T3 aluminum alloy sheets and two layers of glass/epoxy composite lamina. Tensile-tensile cyclic fatigue tests were conducted on centrally notched specimen at four stress levels with various maximum values. A digital camera system was used to take photos of the propagating cracks on both sides of the specimen. Image processing software was adopted to accurately measure the length of the cracks on each photo. The test results show that 1) Compared to 2024-T3 aluminum alloy, the fatigue properties of Glare3-3/2 are much better: under the same loading condition with maximum stress level of 120MPa, the crack growth rate of Glare3-3/2 is roughly 5% of the corresponding value of 2024-T3 aluminum alloy, while the fatigue life is 4 times higher than that of 2024-T3 aluminum alloy. 2) The maximum stress level shows strong influence on fatigue crack propagation behavior of Glare3-3/2. The value of steady state crack growth rate increases linearly, while the number of load cycles decreases exponentially, with respect to the maximum stress values used in the fatigue tests.


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