S111023 Development of Compact Bending Fatigue Test Rig for Plastic Gears in Raman Spectroscopic Analysis

The 20 kHz load frequency enables fatigue tests for very high cycle fatigue life, 109-1013 cycles, within conveniently short time. In automotive applications, many components are subjected to flexural loading and hence bending fatigue is an important test mode. Ultrasound fatigue test instruments have been used successfully in several assessments of fatigue strength and more commonly in uniaxial loading. Here, a 3-point bending fatigue test rig operating in resonance at 20 kHz load frequency has been designed to test plane specimens at R=0.1 loading. The test rig design and stress calculations are presented. Testing for fatigue strength was conducted using the staircase method with 15 specimens of each steel grade, specimens reaching 108 cycles were considered run-outs giving fatigue strength at 108 cycles. Additional 15 specimens of each grade were tested for S-N curves with the upper limit above 109 cycles. Two different common automotive steels, 38MnSiV5, a micro-alloyed ferritic-pearlitic steel, and 16MnCr5, a carburizing martensitic steel, were tested. The fatigue strengths achieved from the staircase testing are 340 and 419 MPa stress amplitudes for the 38MnSiV5 and 16MnCr5 steels, respectively. The S-N curves of the steels appear to be quite flat in the tested life range 107 – 109.

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Bending Fatigue Tests Using a Suitable NDT Method to Determine Lifetime of Large Diameter Wire Ropes for Offshore Lifting Applications

Volume 1: Offshore Technology ◽

10.1115/omae2008-57128 ◽

2008 ◽

Cited By ~ 1

Author(s):

Olav Vennemann ◽

Rikard To¨rnqvist ◽

Bjo¨rn Ernst ◽

Sven Winter ◽

Ian Frazer

Keyword(s):

Fatigue Test ◽

Large Diameter ◽

Fatigue Tests ◽

Wire Rope ◽

Test Rig ◽

Bending Fatigue ◽

Wire Ropes ◽

Bending Fatigue Test ◽

Final Approach ◽

Technical Effort

Wire rope for installations of subsea components offshore have been used for years in different configurations as single-fall or multi-fall. With greater water depths multi fall solutions become more challenging as even low torque ropes induce some torque and great technical effort has to be made to overcome this problem. An alternative solution is the use of a single-fall system employing a large diameter wire rope. Installations are often carried out with the aid of a heave compensation system to keep the load steady during final approach or to pass through resonance zones. As a result such a large diameter wire rope is subjected to frequent bending. It is well known that cyclic bending over sheave (CBoS) can significantly reduce the lifetime of ropes depending on rope utilisation factors and sheave diameters. While there is a lot of data available for smaller rope sizes, very limited data has been generated with large diameter ropes. It was therefore considered necessary to build a bending fatigue test rig and perform bending fatigue tests with the aim of reducing the uncertainty in the fatigue life of large diameter wire ropes. This paper presents the bending fatigue test rig capable of testing O̸109 mm wire rope to up to 330 t, describes the bending fatigue tests carried out and presents bending fatigue test results. Furthermore, results from non-destructive tests, which were frequently performed during the fatigue tests to obtain further information of rope deterioration over its lifetime, will be presented in this paper.

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The Development of Pneumatic Fatigue Test Rig for Wood-Based Specimens

Forests ◽

10.3390/f11111187 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1187

Author(s):

Gorazd Fajdiga ◽

Denis Rajh ◽

Drago Vidic ◽

Bojan Gospodarič

Keyword(s):

Fatigue Test ◽

Development Process ◽

Dynamic Strength ◽

Test Rig ◽

Bending Fatigue ◽

Four Point Bending ◽

Precise Knowledge ◽

Bending Fatigue Test ◽

Numerical Tools ◽

Load Behavior

In product design, the focus is increasingly shifting towards optimizing and increasing the efficiency of the development process. This can be achieved with advanced numerical tools, but these methods require precise knowledge of material properties. One of the desired properties is the dynamic load behavior of the material. The research is directly related with the company that developed the slender wooden beams used in industry to produce windows of larger dimensions (height over 3 m). For the testing of wooden beams, the pneumatic four-point bending fatigue test rig was developed. In this paper, the whole structure of the test rig is described in detail. Based on the performed experiments of dynamic strength, the Woehler curve was determined, which serves as a necessary input for further numerical simulation of the fatigue process of wood-based beams. Knowledge of the response of wood to dynamic loads is very important to predict its life expectancy in various products.

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