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

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.

Large Wire Rope Mooring Winch Drum Analysis and Design Criteria

1980 ◽  
Vol 20 (02) ◽  
pp. 63-74
Author(s):  
K.K. Song ◽  
G.P. Rao ◽  
Mark A. Childers
Keyword(s):  
Modulus Of Elasticity ◽  
Lateral Pressure ◽  
Large Diameter ◽  
Wire Rope ◽  
Wire Ropes ◽  
Analysis And Design ◽  
Number Of Layers ◽  
Inadequate Knowledge ◽  
Wire Strand ◽  
Elasticity Number

Abstract Flange splitting (separation of the flange from the barrel) is the most common structural failure in large mooring winches. Conventionally designed winches have failed on a number of occasions when wire ropes 3 to 3.5 in (7.6 to 8.9 cm) in diameter and up to 10,000 ft (3048 m) long were employed for mooring large construction barges and semisubmersible offshore drilling units. It is believed that this is due to improper approximation of the field loading patterns on the winch, inadequate knowledge of patterns on the winch, inadequate knowledge of actual forces transmitted onto the flange and drum barrel of the winch, and/or defects in the structural joint between the flange and the drum barrel.The available design methods are often empirical, modified, or extrapolated from work done a decade ago using very small wire ropes and drums. The application of these techniques to a multilayered winch using large-diameter wire rope has proved to be unrealistic. A method is presented to calculate the flange thrust load and the barrel external pressure for winches using large-diameter mare ropes. Also, a general guide for design and analysis of such winches and the effect of the lateral modulus of elasticity of wire rope on the reduction in the layer tensions is presented. presented. Introduction Large wire rope winches increasingly are coming into use for offshore construction, pipe laying, and drilling vessels operating in deep water because of the advantages of mooring with wire or a combination of chain and wire as opposed to mooring with chain only. Winches using wire ropes 3 to 3.5 in. (7.6 to 8.9 cm) in diameter, up to 5,000 to 10,000 ft (1524 to 3048 m) long, and stacked up to 15 or more layers under high tensions have been in use. Even larger winches are being contemplated as the search for hydrocarbons and minerals expands into deeper water.An industry-wide survey revealed that several large winches used on lay barges and semisubmersible drilling units have failed in service, exposing the owners to millions of dollars in repair or replacement costs, plus the damaging downtime and delay to the programs on which these units were engaged. An programs on which these units were engaged. An indepth study into the probable causes of these failures revealed that the practical design of large winches remained empirical and that, in some instances, quality control in manufacture was not being taken seriously.Wire ropes, in general, are flattened when lateral pressure is applied. The amount of flattening or pressure is applied. The amount of flattening or compressibility varies according to lateral modulus of elasticity of wire rope, which is defined as the ratio of lateral pressure per unit length of rope to the decrease in rope diameter measured along the lines of pressure. When a wire rope is spooled on a drum, pressure. When a wire rope is spooled on a drum, due to compressibility, the applied line tensions at the middle layers tend to decrease significantly. Thus, the overall structural loading on the winch depends on the lateral modulus of elasticity, number of layers, number of wraps on each layer, and operational tension at each layer. The lateral modulus of elasticity is governed by the rope characteristics such as rope formation, method of weaving, type of core, wire strand and rope diameters, and material properties of core and wire strand. It is known that as the rope gets larger and stiffer, as the number of layers increase, and as the winding tension is maintained at a high level, the resulting forces on the barrel and the side flanges also increase. SPEJ P. 63

scholarly journals Simple determination of the axial stiffness for largediameter independent wire rope core or fibre core wire ropes

2003 ◽  
Vol 38 (6) ◽  
pp. 577-586 ◽  
Author(s):  
M Raoof ◽  
T. J Davies
Keyword(s):  
Large Diameter ◽  
Large Body ◽  
Theoretical Models ◽  
Wire Rope ◽  
Axial Stiffness ◽  
Practical Applications ◽  
Wire Ropes ◽  
Theoretical Predictions ◽  
Computer Based ◽  
Iterative Procedures

Raoof and Kraincanic recently developed two somewhat different theoretical models for analysing large-diameter wire ropes with either an independent wire rope core (IWRC) or a fibre core. Most importantly, unlike all of the previously available theories (with their often very lengthy mathematical formulations), very encouraging correlations have been found between Raoof and Kraincanic's theoretical predictions of wire rope axial stiffnesses and a fairly large body of experimental data from other sources, hence providing ample support for the reliability of both theoretical models. Raoof and Kraincanic's original models were, however, computer based and involved certain iterative procedures. This potential drawback for practical applications (in an area where, by tradition, the rule of thumb reigns supreme) is overcome in the present paper, which reports details of some simplified (but still accurate) procedures for predicting the no-slip and/or full-slip axial stiffnesses of wire ropes with either an independent wire rope core or a fibre core, with the proposed formulations being amenable to simple hand calculations using a pocket calculator, which is of value to busy practising engineers.

EVALUATION OF CRACK INITIATION AND FATIGUE BEHAVIOR OF CrN FILM DEPOSITED ON Ti-6Al-4V ALLOY

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2502-2505 ◽  
Author(s):  
MD. SHAMIMUR RAHMAN ◽  
TAKESHI KATSUMA ◽  
DAISUKE YONEKURA ◽  
RI-ICHI MURAKAMI
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Fatigue Strength ◽  
Tensile Test ◽  
Fatigue Test ◽  
Bias Voltage ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Negative Bias ◽  
Negative Bias Voltage

Titanium alloy has an attractive strength-to-weight ratio and good fatigue properties. However, the titanium alloy has very poor wear resistance, therefore, surface treatments must be considered in order to make the contact parts. Hard thin film deposited by PVD technique is well-known to improve the wear resistance. In this study, chromium nitride ( CrN ) film was applied to titanium alloy and its effect on the fatigue behavior was investigated. Ti -6 Al -4 V alloy was used as a substrate material. The CrN film was deposited by arc ion plating (AIP) method at two different negative bias voltages because the film hardness, crystal orientation and surface morphology were strongly depended on the bias voltage during the deposition. Tension-tension fatigue test and tensile test were carried out to investigate the fatigue properties. As the result, the fatigue strength was influenced by the deposition of the CrN film, especially, the fatigue strength was remarkable decreased by the deposition of the CrN film at high negative bias voltage compared to the uncoated specimen and the deposition of the CrN at low negative bias voltage. The difference of the fatigue strength was also investigated on the basis of crack initiating behavior during fatigue test and tensile test.

scholarly journals Influence of testing environment on static fatigue behavior of a glass and a polycrystalline ceramic

2021 ◽  
Vol 32 (3) ◽  
pp. 56-64
Author(s):  
Sara Fraga ◽  
Gabriel Kalil Rocha Pereira ◽  
Luís Felipe Guilardi ◽  
Liliana Gressler May ◽  
Luiz Felipe Valandro ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Fatigue Behavior ◽  
Slow Crack Growth ◽  
Lithium Disilicate ◽  
Static Fatigue ◽  
Distilled Water ◽  
Step Size ◽  
Test Environment ◽  
Time To Fracture

Abstract It aims on evaluate the effect of the test environment on static fatigue behavior of lithium disilicate-based (LD), and yttrium oxide-stabilized zirconia (YSZ) ceramics. Specimens of LD (IPS e.max CAD, Ivoclar Vivadent) and YSZ (IPS e.max ZirCAD MO, 3 mol% Y2O3, Ivoclar Vivadent) were randomly allocated into three groups: tested in air, inert (paraffin oil, Sigma Aldrich) or distilled water. The static fatigue test (n=15) was performed using a piston-on-three ball assembly, adapted from ISO 6872, as follows: starting load 100 N for LD and 300 N for YSZ; loading application time set to 1 hour for each loading step; step size of 50 N for LD and 100 N for YSZ, applied successively until fracture. Data from static fatigue strength (MPa) and time to fracture (hours) were recorded. Fractographic analysis was executed. Survival analysis corroborates absence of influence of environment on static fatigue outcomes (fatigue strength, time to fracture and survival rates) for YSZ. For LD, specimens tested in air presented statistically superior survival rate and static fatigue strength (p= 0.025). In regards of time to fracture, LD tested in air were superior than when tested in distilled water (p=0.019) or inert (p=0.017) environments. No statistical differences for Weibull modulus were observed. Failures started on the tensile stress surface. Thus, the test environment did not affect slow crack growth (SCG) mechanisms during static fatigue test of YSZ ceramics, but it plays a significant role for the static fatigue behavior of lithium disilicate-based glass ceramics, indicating a high susceptibility to SCG.

Fatigue Behavior of Extruded Mg-Al-Ca-Mn Alloy with T6 Treatment at Elevated Temperature

2014 ◽  
Vol 627 ◽  
pp. 417-420 ◽  
Author(s):  
Yukio Miyashita ◽  
Hugo Inzunza ◽  
Adrian Elizondo ◽  
Yoshiyuki Murayama ◽  
Yuichi Otsuka ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Fatigue Strength ◽  
Fatigue Test ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Property ◽  
Propagation Behavior ◽  
Replication Technique

Fatigue behavior of Mg-Al-Ca-Mn alloy with T6 treatment was studied at room temperature and 150°C by conduction rotating bending fatigue test. Fatigue strength at high temperature was lower than that at room temperature in the alloys with and without heat treatment. However, degradation of fatigue strength at high temperature in the T6 treated alloy was not significant compared to the as-extruded alloy. Fatigue crack initiation and propagation behavior was observed with replication technique by conducting interrupted fatigue test at room temperature and 150°C. Multiple cracking was significantly observed at 150°C in both as-received and T6 treated alloys. Change in grain size and randomization of crystal orientation due to the heat treatment could affect the fatigue property.

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.

Fatigue Test Research for SPR Aluminum Alloy Sheet

2010 ◽  
Vol 44-47 ◽  
pp. 2557-2561 ◽  
Author(s):  
Jing Hua Zhao ◽  
Shu Min Wan ◽  
Shuang Yi Li ◽  
Feng Liu
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Test ◽  
Spot Welding ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Alloy Sheet ◽  
Regression Analyses ◽  
Factor Analyses ◽  
Test Parameters ◽  
Damage Rule

In this paper, the fatigue behavior of self-piercing riveting (SPR) joints is compared with resistance spot welding (RSW) joints for the same A6063 aluminum alloy sheets. The fatigue test, where every specimen is tested under different load, is conducted on MTS810.23M testing machine, and the results show that SPR joints have superior fatigue performances. Next S-N curve of every specimen is deduced after regression analyses of test data and the fatigue damage rule of SPR aluminum alloy sheets is summarized. Finally the effect of test parameters and errors on fatigue life of RSW and SPR joints is evaluated with two-factor and multiple factor analyses of variance.

Effects of Roller Working and Ion Nitriding on Fatigue Properties of Eutectoid Steel

2007 ◽  
Vol 340-341 ◽  
pp. 519-524
Author(s):  
Mian Zhang ◽  
Shinichi Nishida ◽  
Nobusuke Hattori ◽  
Wen Xian Sun
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Surface Hardness ◽  
Fatigue Properties ◽  
Eutectoid Steel ◽  
Ion Nitriding ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

In this study, the authors have investigated and compared the effects of roller working and ion nitriding on fatigue properties of eutectoid steel. Five kinds of roller worked and two kinds of ion nitrided specimens were used in this test. The fatigue test was performed using a rotating bending fatigue testing machine to evaluate the fatigue strength of roller worked and ion nitrided eutectoid steel. The fatigue test result shows that roller working is more effective on improving the fatigue strength of the material than ion nitriding. On the other hand, the ion nitriding can much greatly increase the surface hardness than the roller working. In the case of roller working, the fatigue properties are improved by the three main factors which are compressive residual stress, work hardening and fiberized micro-structure.

ULTRASONIC FATIGUE BEHAVIOR OF A Fe-BASED WARM-COMPACTED POWDER METALLURGY MATERIAL

2013 ◽  
Vol 27 (19) ◽  
pp. 1341027
Author(s):  
YU-HENG LU ◽  
XUAN YE ◽  
LEI HU ◽  
FEI LUO ◽  
ZHI-YU XIAO
Keyword(s):  
Heat Treatment ◽  
Powder Metallurgy ◽  
Fatigue Strength ◽  
Fatigue Test ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Powder Metallurgy Material ◽  
Ultrasonic Fatigue ◽  
Ultrasonic Fatigue Test ◽  
Axial Fatigue

Fe -2 Cu -2 Ni -1 Mo -1 C powder metallurgy material was fabricated by die-wall lubricated warm compaction and ultrasonic fatigue test was carried out for as-sintered and heat treatment samples. Material fatigue strength reaches 249 MPa under axial fatigue testing. The sintered material consists of acicular martensite, pearlite, bainite and retained austenite. Tempered martensite is the major phases after heat-treatment. Cleavage plane and dimples is mixed fracture for sample after axial fatigue test. Mechanical properties of after heat treatment materials are improved and fatigue strength reaches 382 MPa under 107 cycles in bending ultrasonic fatigue test. The fatigue strength increases significantly in high cycles range.

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