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

2008 ◽  
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.

scholarly journals 20 kHz 3-point bending fatigue of automotive steels

2018 ◽  
Vol 165 ◽  
pp. 22020
Author(s):  
Mohamed Sadek ◽  
Jens Bergström ◽  
Nils Hallbäck ◽  
Christer Burman
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Pearlitic Steel ◽  
Fatigue Tests ◽  
Test Rig ◽  
Staircase Method ◽  
Bending Fatigue ◽  
Load Frequency ◽  
Bending Fatigue Test ◽  
Short Time

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.

Effects of Overload on Fatigue Strength of SUS316 Having a Crack-Like Surface Defect

2010 ◽  
Author(s):  
Hiroko Oosedo ◽  
Koji Takahashi ◽  
Kotoji Ando
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Surface Defect ◽  
Compact Tension ◽  
Crack Size ◽  
Fatigue Tests ◽  
Stress Intensity Factor Range ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Key Factor

The effects of overload on the fatigue strength and threshold stress intensity factor range (ΔKth) in SUS316 were studied. Tensile overload was applied to compact tension (CT) specimens with a large crack and fatigue tests were carried out to determine the ΔKth. Tensile or compressive overload was applied to bending fatigue test specimens with a small crack-like surface defect and fatigue tests were carried out to determine the fatigue limit and ΔKth. It was found that the ΔKth increased by tensile overloading. The increasing rate of ΔKth in the CT specimen is larger than that in the bending fatigue test specimen. Thus, the crack size effects on the improvement of ΔKth after overloading were observed. The results are discussed from the viewpoint of fracture mechanics. The size of compressive residual stress is the key factor of the increasing rate.

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.

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

2013 ◽  
Vol 2013 (0) ◽  
pp. _S111023-1-_S111023-5
Author(s):  
Yusuke KAWAGOE ◽  
Daisuke IBA ◽  
Morimasa NAKAMURA ◽  
Leonardo PUPPULIN ◽  
Giuseppe PEZZOTTI ◽  
...  
Keyword(s):  
Fatigue Test ◽  
Spectroscopic Analysis ◽  
Test Rig ◽  
Bending Fatigue ◽  
Raman Spectroscopic ◽  
Bending Fatigue Test ◽  
Plastic Gears ◽  
Raman Spectroscopic Analysis

Application of Infrared Imaging Technology in Fatigue Failure Prediction of Vehicle Wheel in Wheel Bending Fatigue Test

2016 ◽  
Author(s):  
W. H. Chai ◽  
X. D. Liu ◽  
Y. C. Shan ◽  
J. G. Wang
Keyword(s):  
Temperature Distribution ◽  
Real Time ◽  
Fatigue Test ◽  
Fatigue Failure ◽  
Infrared Imaging ◽  
Bending Moment ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Time Prediction ◽  
Bending Fatigue Test

Bending fatigue test of vehicle wheel is the main test to verify the mechanics performance of spoke. The wheel is fastened to the bending fatigue test platform with bolts in the bending fatigue test. A cyclic bending moment is applied to the wheel, and after some number of cycles, fatigue failure will happen. In this paper, the bending fatigue test is carried out on a steel wheel and a wheel made of long glass fiber reinforced thermoplastic (LGFT) wheel, and infrared imager is used to monitor the temperature distribution and variation of wheels under bending loads in the test process. After the test, it is found that there are cracks at the highest-temperature spots. In addition, because some cracks of LGFT wheel are too tiny to be found, it’s convenient to search those cracks according to the high-temperature areas in infrared images. All above indicate that it is practicable to predict fatigue failure area by monitoring temperature distribution and variation in wheel bending fatigue test. A method for real-time prediction of fatigue failure area in wheel bending fatigue test is described in this paper, which is also helpful to real-time prediction of fatigue failure area in fatigue tests of other products.

Characterization of a resonant bending fatigue test setup for pipes

2011 ◽  
Vol 2 (3) ◽  
pp. 424-431
Author(s):  
Jonas Claeys ◽  
Jeroen Van Wittenberghe ◽  
Patrick De Baets ◽  
Wim De Waele
Keyword(s):  
Fatigue Test ◽  
Analytical Model ◽  
Stress Amplitude ◽  
Fatigue Tests ◽  
Steel Pipe ◽  
Bending Fatigue ◽  
High Frequencies ◽  
Test Setup ◽  
Bending Fatigue Test

This paper discusses the resonant bending fatigue test setup designed at laboratory Soete forfull-scale fatigue tests on pipes. Following an enumeration of other types of fatigue test setups an attempt ismade to characterise the resonant bending machine. The characterisation is obtained by conductingdifferent tests on a steel pipe of grade API X65. Concordance between measured and calculated stressesand influence of excentre position on stress amplitude is discussed. High frequencies and small powerinput make this test setup very effective. The analytical model correctly predicts the measured stresses anda stress versus excentre curve is obtained. However not yet fully defined, it gives a first indication for theexcentre position when preparing for a fatigue test.

Fatigue Behavior of Large-Diameter Wire Ropes

1982 ◽  
Vol 22 (03) ◽  
pp. 420-428 ◽  
Author(s):  
M. Hanzawa ◽  
H. Yokota ◽  
Y. Toda ◽  
K. Yokoyama
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Fatigue Behavior ◽  
Large Diameter ◽  
Testing Machine ◽  
Wire Rope ◽  
Suspension Bridges ◽  
Wire Ropes ◽  
Wire Breakage ◽  
Tensile Fatigue

Abstract Factors influencing tensile fatigue strength of 50-mm wire ropes were investigated with a wire-breakage detecting system. The fatigue strength increased with an increase in wire strength and diameter and a decrease in self-rotativity of ropes. The epoxy resin was satisfactory as a socketing material. Introduction More and more offshore oil wells are being drilled in deeper waters. For the purpose of economy, offshore structures for deepsea use, such as the tension leg platform (TLP) and guyed tower, are moored by wire ropes. The wire ropes used in such applications directly receive the loads repeatedly applied by waves and tides. Therefore, the fatigue behavior of wire rope is an important factor in the design of such offshore structures. Wire ropes are used also for long-span suspension bridges such as those being constructed to connect Honshu and Shikoku in Japan. In such bridges, the fatigue strength does not cause problems for main cables receiving little live load, but it is important for hanger ropes on which bridge traffic imposes much live load. Thus, there is a strong demand to determine fatigue characteristics and clarify fatigue behavior in relation to tensile breaking load of such large-diameter wire ropes-i.e., size range of 85, 130, and 180 mm.Most conventional wire rope fatigue data have been obtained by bending tests. Few tensile fatigue test data are available, and those are mainly for small-diameter wireropes (6.4 and 12.7 mm).Few reports have been made for larger-diameter wire ropes and the fatigue tests conducted have given no specific definition of fatigue life. The best attempt has been visual examination of broken wire in the outermost layer of the wire rope. In the fatigue test of large-diameter wire ropes comprising a large number of wires, however, wire breakage does not always occur in the outermost layer, but can take place in the inner layers and even in sockets under certain conditions. To determine the fatigue strength of large-diameter wire ropes exactly, therefore, it is necessary to detect wire breakage during the fatigue test and thereby determine fatigue life.It was against such a background that a device for detecting wire breakage in wire rope being fatigue tested was developed by making use of acoustic emission (AE) and an accelerometer. With this device, tensile fatigue tests have been conducted on various kinds of 50-mm-diameter wire ropes that were similar to practical wire rope in construction and strength. A study comparing test results was conducted on factors affecting the fatigue strength of large-diameter wire ropes, along with an investigation on socketing materials having high fatigue performance. Experimental Procedure Commercial large-diameter wire ropes are manufactured with many diameters - e.g., hanger ropes for long-span suspension bridges are 85 mm, those for guyed towers are 130 mm, and those for TLP's are 180 mm. To test full-size wire ropes, a fatigue-testing machine should have a capacity of more than 4 MN.Only a 2-MN fatigue-testing machine was available, so the maximum testable nominal diameter was 50 mm. Therefore, wire ropes having a 50-mm nominal diameter were prepared with wires having the same strengths and similar constructions as those of full-size commercial wire ropes. Table 1 lists the specifications of the fatigue-tested wire ropes. Ropes 9S6, 9SL6, 6S7, and 6S8 are of the center-fit-rope-core (CFRC) type for hanger-rope use. SPEJ p. 420

scholarly journals Three-Point Bending Fatigue Test of TiAl6V4 Titanium Alloy at Room Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Juraj Belan ◽  
Lenka Kuchariková ◽  
Eva Tillová ◽  
Mária Chalupová
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Room Temperature ◽  
Fatigue Tests ◽  
Dynamic Force ◽  
Bending Fatigue ◽  
Three Point Bending ◽  
Bending Fatigue Test ◽  
Number Of Cycles ◽  
Test Loading

A polycrystalline alpha-beta TiAl6V4 alloy in the annealed condition was used for the three-point bending fatigue test at frequency f∼100 Hz. The static preload Fstat. = −15 kN and variable dynamic force Fdyn. = −7 kN to −13.5 kN were set as fatigue test loading parameters. The fatigue life S-N curve presented the stress amplitude σa as a function of a number of cycles to fracture Nf. A limiting number of cycles to run out of 2.0 × 107 cycles were chosen for the 3-point fatigue tests of rectangular specimens. In addition, the Smith diagram was used to predict the fatigue life. The alpha lamellae width has a significant influence on fatigue life. It is assumed that the increasing width of alpha lamellae decreases fatigue life. A comparison of fatigue results with given alpha lamellae width in our material to the results of other researchers was performed. The SEM fractography was performed with an accent to reveal the initiation sites of crack at low and high load stresses and mechanism of crack propagation for the fatigue part of fracture.

Stress Calculation of Fillet Rolled Crankshaft in Bending Fatigue Tests

2010 ◽  
Vol 44-47 ◽  
pp. 2798-2804 ◽  
Author(s):  
Ke Bao ◽  
Ri Dong Liao ◽  
Zheng Xing Zuo
Keyword(s):  
Residual Stresses ◽  
Fatigue Test ◽  
Three Dimensional ◽  
Rolling Process ◽  
Fatigue Tests ◽  
Superposition Method ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Bending Stresses ◽  
Three Dimensional Finite Element

The stresses around the fillet of fillet rolled crankshaft section in bending fatigue test are quite complicated, which include the residual stresses induced by fillet rolling process and bending stresses caused by bending fatigue test loads. In this paper, the corresponding three dimensional finite element models of roller- shaft are created and the residual stresses near the fillet of crankshaft section are obtained by flexible-flexible contact computation. Then the transient analysis of bending fatigue test based on modal superposition method is carried out and the bending stresses are got. The results of stress can be used to the bending fatigue design of crankshafts.

On the Design of the In-Plane Bending Fatigue Test

2013 ◽  
Author(s):  
Geir Agustsson ◽  
Erik Bendiksen ◽  
Christian B. Nielsen
Keyword(s):  
Fatigue Test ◽  
Test Methods ◽  
Fatigue Tests ◽  
Field Conditions ◽  
Flexible Pipe ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Life Model ◽  
Plane Bending ◽  
Full Scale Tests

The fatigue design of the steel armour layers is an important factor in flexible riser design. Typically, the riser must be able to endure the loads of a field condition for a period of 20 years. In flexible pipe design, this is analyzed in global and local flexible pipe fatigue modeling, which needs to be supported by proper testing. One of the widespread test methods is the so-called in-plane bending fatigue test, which is one of the important qualification tests for flexible pipes. API 17B references two purposes for performing in-plane bending fatigue tests. One is to demonstrate that the pipe can endure the loads which it is exposed to during its lifetime (service simulation). The other is to validate the design methodologies (service-life model validation). The first purpose calls for test conditions being as close to reality as possible. However, testing in conditions close to reality does not necessarily call for field environment conditions being present during the in-plane testing itself. This is because field conditions are covered with a combination of small-, mid- and full-scale tests according to the recommendations given in API 17B. The second purpose can be, or is even best fulfilled with simplifications compared to field conditions. This study will go through the options and discuss the pros and cons of simplifications versus a more complicated test. The discussions in the paper are based on the author’s experience and can be supported with examples from actual testing.

Sign in / Sign up

Export Citation Format

Share Document