Design of Threaded Fatigue Test Specimen for Machining

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Hamza K. Akyildiz ◽  
Haydar Livatyali
Keyword(s):  
Fatigue Test ◽  
Test Section ◽  
Test Specimen ◽  
Fatigue Testing ◽  
Complex Geometry ◽  
Testing Machine ◽  
High Strength ◽  
Critical Test ◽  
Fatigue Notch Factor ◽  
Center Section

Design and machining of the fatigue test specimens have significant effects on the duration and reliability of fatigue test. Fatigue test specimens essentially consist of three parts: the center or critical test section, which is the region where required conditions are simulated as closely as possible, and the two ends, which serve to transfer the load from the grips to the center section. When high strength materials are used for a complex geometry, such as a thread need to be tested, design and manufacturing of the specimens become more influential on the reliability and duration of the tests. Threaded fatigue test specimens were designed, machined, and tested in a four-point rotary bending fatigue testing machine. An innovative threaded fatigue test specimen that consistently fails at the critical test section was designed, machined, and tested successfully to give the required fatigue notch factor. Because of full scale fatigue testing with threaded parts is very expensive and sometimes dangerous, evaluated threaded fatigue specimen can be used in fatigue testing and it reduces duration of the experiment more than 60% for machined threaded specimens.

Tensile Tests with Flat (Straight) Test-Specimens

1938 ◽  
Vol 11 (1) ◽  
pp. 214-223
Author(s):  
R. Ariano
Keyword(s):  
Test Specimen ◽  
Testing Machine ◽  
American Chemical Society ◽  
Tensile Tests ◽  
Chemical Society ◽  
Ring Test ◽  
Rubber Ring ◽  
Long Time ◽  
Fundamental Objection ◽  
Center Section

Abstract It is of course a well known fact that both ring test-specimens and flat or straight test-specimens are used in testing rubber. Ring test-specimens have for a long time been the most generally used type for testing rubber mixtures, whereas in American laboratories straight test-specimens are preferred. Ring test-specimens are the more convenient to use, but they are open to one fundamental objection, that different parts of the cross section of the rubber are elongated to different extents at any particular moment. Even straight test-specimens are not free from objectionable features. With this type of test-specimen, the inequality in the deformation at any particular instant results from the necessity of having enlarged ends for the testing machine to avoid breakage of the test-specimens in the jaws. It therefore becomes necessary to study systematically the form and dimensions of the end sections of the test-specimens and of the junction of these end sections with the central section, so that the points of rupture will not become localized in the sections in the jaws or close to these sections. As a matter of fact, an extensive investigation of this problem has been made by the Physical Testing Committee of the Rubber Division of the American Chemical Society. By a proper study of the shape of the test-specimen, it is possible to design the test-specimen so that rupture occurs in the center section and therefore so that satisfactory tensile strength measurements are obtained.

Fretting Fatigue Testing of Carburized Alloy Steel in Very High Cycle Regime Using an Ultrasonic Torsional Fatigue Testing Machine

2014 ◽  
Vol 891-892 ◽  
pp. 1152-1156
Author(s):  
Yoshinobu Shimamura ◽  
Akito Kokubo ◽  
Hitoshi Ishii ◽  
Keiichiro Tohgo ◽  
Tomoyuki Fujii ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
Testing Machine ◽  
Fatigue Property ◽  
High Strength ◽  
Fretting Fatigue ◽  
Testing Method ◽  
Torsional Fatigue ◽  
Alloy Steels ◽  
Strength Alloy ◽  
Very High

Recently, high-strength alloy steels have been developed and used for various products. It is well known that fretting fatigue does not show fatigue limit. In other words, fretting fatigue failure may occur in very high cycle regime more than 107 cycles. However, it is difficult to investigate fretting fatigue property in very high cycle regime by using conventional fatigue testing machines because it is time-consuming. In this study, a fretting fatigue testing method for carburized alloy steels in very high cycle regime is explored by using an ultrasonic torsional fatigue testing machine. Carburized SCM420H was used for investigation. The experimental results showed that it is possible to conduct fretting fatigue testing of carburized alloy steels by using an ultrasonic torsional fatigue testing machine.

Fatigue Behaviour of Friction Stir Welded AZ31B Magnesium Alloy Joints

2015 ◽  
Vol 787 ◽  
pp. 355-360
Author(s):  
S. Venkatesan ◽  
G.P. Rajamani ◽  
V. Balasubramanian ◽  
G. Padmanaban
Keyword(s):  
Fatigue Strength ◽  
Fatigue Testing ◽  
Corrosion Behaviour ◽  
Testing Machine ◽  
Fatigue Behaviour ◽  
Fusion Welding ◽  
Sensitivity Factor ◽  
Metal Fatigue ◽  
Friction Stir ◽  
Fatigue Notch Factor

Friction stir welding (FSW) is a relatively better joining technique particularly for magnesium and aluminum alloys that are difficult to weld by fusion welding techniques. Fusion welding of these alloys is not preferable due to hot cracking, formation of porosity, etc. However solid state welding techniques, such as, friction sitr welding are found to offer solution to the above problems. Many research papers available in open literature focusing tensile properties, microstructural characteristics, and corrosion behaviour of friction stir welded AZ31B magnesium alloys but fatigue behaviour of these welds are not yet investigated. Hence, in this investigation, an attempt has been made to evaluate fatigue behaviour of friction stir welded rolled plates of AZ31B magnesium alloys.Fatigue experiment was conducted using servo hydraulic controlled fatigue testing machine. Fatigue strength, fatigue notch factor and notch sensitivity factor were evaluated. It is found that the fatigue strength of AZ31B welded joints is 46 MPa at 2x106cycles which is approximately 34 % lower than that of the base metal fatigue strength.

scholarly journals Test Results of Wheel-Axle Fatigue Testing Machine : Report 1, Fatigue Test under Constant Load

1968 ◽  
Vol 34 (268) ◽  
pp. 2092-2102
Author(s):  
Hiroshi NAKAMURA ◽  
Shinichi TANAKA ◽  
Kozo HATSUNO ◽  
Shinji YAGUCHI ◽  
Bunpei MORI
Keyword(s):  
Fatigue Test ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Constant Load ◽  
Test Results

scholarly journals Development of Fatigue Testing Machine for Thin Sheet Specimen and Fatigue Test for Magnesium Single Crystal

2009 ◽  
Vol 58 (8) ◽  
pp. 703-708 ◽  
Author(s):  
Masayuki TSUSHIDA ◽  
Ryosuke IKEDA ◽  
Hiromoto KITAHARA ◽  
Shinji ANDO
Keyword(s):  
Single Crystal ◽  
Fatigue Test ◽  
Fatigue Testing ◽  
Thin Sheet ◽  
Testing Machine

Fatigue Strength of Ion Nitrided Tool Steel

2006 ◽  
Vol 324-325 ◽  
pp. 475-478
Author(s):  
Mian Zhang ◽  
Shinichi Nishida ◽  
Nobusuke Hattori
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Tool Steel ◽  
Surface Composition ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Surface Hardness ◽  
Fatigue Properties ◽  
Ion Nitriding ◽  
Rotating Bending Fatigue

The authors have studied and clarified that ion nitriding was able to improve the fatigue properties of tool steel. Five kinds of ion nitriding methods (ion nitriding condition is different) were used in this study. The fatigue test had been performed using a rotating bending fatigue testing machine to investigate the effects of ion nitriding on fatigue properties of tool steel. The fractography was analyzed using a scanning electron microscope (SEM), and hardness distribution was also investigated using a microhardness tester. As a result, the fatigue strength and hardness of the ion nitrided specimen increased after ion nitriding processing. It is considered that the compressive residual stress which produced by ion nitriding processing in the layer reduced fatigue fracture, and the altered surface composition improved surface hardness. According to the results of the fatigue test, the optimal ion nitriding method on improving the fatigue limit of tool steel was determined. The hardness of the specimens remarkably increased after ion nitriding processing.

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