Experimental methodologies to study fretting fatigue damage. The fraction of fretting fatigue lifetime spent in crack. The data used to make this figure were determined using a matlab script file. Mar 23, 2017 a fretting fatigue life estimation method that takes into account the stress gradient effect was developed by the authors journal of mechanical science and technology, 28 2014 21532159. Influence of frelllng on flexural fatigue of 304 stainless steel and mild steel by robert c. Cyclic load testing coated fan blades were tested at a 20 mt 44,000 lb pull load and cycled to coating failure. Numerical modelling of fretting fatigue crack initiation. Fretting fatigue has been responsible for a large number of service failures across a wide range of applications. As the cof varies along the direction of motion the fretting loop given by. The asm handbook on fatigue and fracture defines fretting as. The second one is an online detection methodology for fretting fatigue crack initiation. A novel approach to model frettingfatigue in multiaxial and non. Pdf this thesis presents theoretical computational, and experimental approaches to the problem of fretting fatigue in materials systems.
Specimens designed to reproduce the state of stress of the dovetail joint between blade and disk in a typical gasturbine configuration have been tested in a 250kn capacity biaxial fatigue machine. Additional testing fatigue testing is one type of relevant bench testing for occluders and closure devices. Mechanics of fretting fatigue pdf free download kundoc. Eight straps were subjected to an ultimate tensile strength test. The investigation highlights the importance of fretting at the diskblade interface. Experiments have become more standardised and carefully controlled and this has provided the data.
The functionality of the device is examined by making a comparison between fretting fatigue lives of a number of al7075t6 specimens tested on an instron testing machine and vcsd. Hills department received of engineering science, university of oxford, parks road. This failure mode can occur with aerofoil excitation in either flap or torsional modes, and it is the type of fretting most likely to result in problems of fretting fatigue ref. Development of predictive finite element models for complete contact fretting fatigue a thesis submitted to the university of manchester for the degree of doctor of philosophy phd in the faculty of engineering and physical sciences 2015 mohamad haidir maslan school of mechanical, aerospace and civil engineering. However, over the last 16 years there was a progress in test rigs both qualitative and quantitative that is not yet summarized. Fretting wear and fatigue analysis of a modular implant. The importance of the size effect is highlighted and an analogy is made between fretting and notch fatigue. Suresh a systematic investigation of the fretting fatigue behavior of. Frettingfatigue behavior of steel wires in low cycle. These experiments confirm the existence of a size effect whereby the fretting fatigue life of an aluminium alloy is shown to vary with contact size. Click here to see several clear photos of fretting which resulted in fatigue fracture. The axial load waveform is a sine wave, planeplane contact.
Rohn lewis research center summary fretting fatigue experiments were conducted on 304 stainless steel and on mild steel. Fretting fatigue denotes the initiation and propagation of cracks in the contact zone, even when the stresses are below the critical values at pure fatigue conditions. The geometry of the components exposed to fretting and the load conditions will affect the type and the amount of damage in a number of ways. This damage is induced under load and in the presence of repeated relative surface motion, as induced for example by vibration. An analysis of fretting fatigue palliatives, focusing on shot peening and coatings. Fatigue failure occurred even when every stress was below the constant amplitude fretting fatigue limit diagram. Performing organization name and address quality and integrity design engineering center qedec department of mechanical engineering university of utah. Fretting loop is a hysteresis plot for coefficient of. Fretting fatigue failure process can be divided into two different categories of mechanical failure process namely, fretting and fracture failures. Selective leaching is a form of corrosion that results from chemical differences not within grain boundaries but within the grains themselves11 and is defined as the removal of specific components of an alloy from the devices surface, initiated by weakly bound or readily solvable elements and.
A unified fracture mechanics approach to fretting fatigue crack. Fretting fatigue strength and life estimation considering the fretting wear process t. The combined role of frettingfatigue and dynamic torsional load causes the tensiontorsion multiaxial frettingfatigue of steel wires, which results in the wear and fracture of steel wires. Fretting corrosion has been the cause of countless failures at the contact points of machinery components. Suresh a systematic investigation of the fretting fatigue behavior of the titanium alloy ti6al4v in both. The combined role of fretting fatigue and dynamic torsional load causes the tensiontorsion multiaxial fretting fatigue of steel wires, which results in the wear and fracture of steel wires. Fretting fatigue is the fatigue damage phenomena due to cyclic stress on the components affected by fretting and reduces the fatigue life extensively compared with nonfretting fatigue. An experimental investigation of fretting fatigue in ti. Wawrzynek and tony ingraffea 9, which is used to extract stress intensity factors sif history files.
Department of mechanical, materials and manufacturing engineering representative fretting fatigue testing and prediction for splined couplings. Astm e2789102015 standard guide for fretting fatigue. Mutoh of japan will coordinate and chair the next meeting with support from the fret ting fatigue community of japan. The fretting fatigue life, the friction load are also measured by using foil strain gauges using a wheatstone bridge configuration. The test configuration was a flexural fatigue arrangement, with mild steel fret. Fretting simulation for crankshaftcounterweight contact. Using the results of fatigue tests of hinge joints from different materials the graph of efficient ratio of fatigue as function of frettingfactor pcut is made.
Current technology and practices at the conclusion of the symposium the planning committee for the next two symposia was formed. Considerable progress has been made in the understanding of fretting fatigue over the last decade. This thesis describes a series of fretting fatigue experiments carried out under closely controlled conditions of partial slip. The greatest reduction in fatigue strength occurs when the fretting process and cyclic. An experimental investigation of fretting fatigue in ti6al4v.
Two methodologies are developed based on infrared thermography. An investigation of fatigue and fretting in a dovetail. It is present in assemblies like rivet and screw fixture, dovetailjoint, shaft and hub with key, and all connections of two bodies with a contact force and a small induced relative displacement. In total, 26 straps were subjected to a fretting fatigue test, of which ten did not fail. Fretting fatigue limit diagram and nonpropagating crack of condition a. Fretting damage has been reported and investigated for over 50 years. Fretting fatigue strength and life estimation considering. For example, fretting in railway axles was reported by maxwell et al. This paper focuses on the fretting fatigue behaviour of pinloaded carbonfibrereinforced polymer cfrp straps studied as models for rigging systems in sailing yachts, for suspenders of arch bridges and for pendent cables in cranes. This projection piece reduces the local stiffness and releases the pressure and stress concentration near contact edge. In addition, hydrogen can cause further reduction of fretting. Fretting fatigue, which is composite phenomenon of metal fatigue and tribological action fretting wear, is one of the most important factors in the design of mechanical component involving contact part, because fretting significantly reduces the fatigue strength of the contact part.
Recent developments in the understanding of fretting fatigue. Fretting is a special wear process that occurs at the contact area between two. An analysis of fretting fatigue ora oxford university. Corrosion testing, particulate testing, nickel leachability and other mechanical tests may also be required depending on your device. It is defined as deterioration at the interface between contacting surfaces as the result of corrosion and a slight oscillatory slip between. Extended finite element method for fretting fatigue crack propagation e. The deleterious effects of fretting on the fatigue properties of a material have been known since the work of warlowdavies in 1941. Fretting fatigue in marine diesel engine bedplate bearing. The test environment is the atmospheric environment and room temperature.
Fretting fatigue properties in hydrogen containing ppm. However, if you are more interested to some issues such as cpu time and so one for specific problem such as fretting fatigue contact, it would be good idea to compare them together. Fretting is related to tribological behavior of interface surfaces of bodies which are in contact and fracture behavior is more related to fracture mechanics properties of bulk material. Fretting is a special wear process that occurs at the contact area between two materials under load and subject to minute relative motion. Some of these parameters include differing materials, relative displacement amplitudes, normal force at the fretting contact, alternating tangential force, the contact geometry, surface integrity parameters such as finish, and the environment. Hills i mechanics of fretting fatigue 1 under these conditions, modelling of the final phase of the initiation process will be even more difficult, as the crack exists in an anisotropic material, and the influence of nearby grain boundaries or crystallographic orientation will. Solutions flash improved antifretting solution for. Therefore, amdry 958 antifretting coatings are less likely to cause disc wear. The failure of the blade root is caused by frettage fatigue cracking of the root, which then acts as a stress concentration.
Combination of fatigue due to bulk stress which cause gross alternating movement, and microsliding due to fretting. Clickhere to see several clear photos of fretting which resulted in fatigue fracture. Extended finite element method for fretting fatigue crack. A special wear process that occurs at the contact area between two materials under load and subject to minute. This guide is not intended to establish preference of one apparatus or specimen design over others, but will establish guidelines for adherence in the design, calibration, and use of fretting fatigue apparatus and recommend the. While these studies and models are useful for fatiguebased mechanisms, they do not address the challenge of modeling abrasiveadhesive wear mecha. Nishimura department of mechanical and system engineering, gifu university, japan abstract in this paper we present the estimation methods of fretting wear process and fretting fatigue life using this wear process. The first one is an offline method for rapid determination of the fretting fatigue limit. Topic of studies for decades, the researchers perform experimental tests with some simplification in order to accelerate the.
A fretting fatigue life estimation method that takes into account the stress gradient effect was developed by the authors journal of mechanical science and technology, 28 2014 21532159. Fretting refers to wear and sometimes corrosion damage at the asperities of contact surfaces. To this end in this section, two commercial fe packages, namely ansys and abaqus are compared to analyse the fretting fatigue bridge type flat contact configuration. However, it is still one of the modern plagues for industrial machinery 6. Preventing fretting fatigue in blade dovetail roots by. S sliding displacement, in mm k material constant 103. Movement can be as short as 1 micron, due to mechanical vibration can be a microscopic contact within the contact area, without gross sliding damage is hidden in contact area. The fretting fatigue properties were investigated on laser peened 7075t6 aluminium alloy clauer and fairand, 1979 using dogbonetype specimens as shown in fig. Nishioka and hirakawa, fundamental investigations in fretting fatigue, part 5 the effect of slip amplitude bull.
Fretting corrosion can reduce the endurance limit of steels to as little as 18% of their original values. Under fretting conditions, fracture cracks can initiate at very low stresses, well below the fatigue limit of nonfretted specimens. Astm e2789 102015 standard guide for fretting fatigue. The fretting fatigue test condition and parameters are as follows. Fretting fatigue occurs when two contact bodies undergo small oscillatory relative motion due to cyclic loading. Fretting corrosion and erosion is corrosion assisted by mechanical action.
Pdf a study of fretting fatigue in aircraft components. Polymers free fulltext fretting fatigue behaviour of. The crack can then propagate across the root due to high cycle fatigue, ultimately leading to complete failure of the blade. This projection piece reduces the local stiffness and releases the. In this test, coatings of amdry 958 performed nearly twice as well as the nearest conventional antifretting coating, demonstrating that. Figure 6 shows the development of surface cracks in a ti6al4v alloy due to fretting fatigue. Therefore, numerical analysis, such as finite element analysis fea, would be useful to. The severity of this type of fretting can be minimized by ensuring. According to mutoh mutoh, 1997, the crack path of fretting fatigue is classified into. Houghton, dean 2009 representative fretting fatigue. The methodology is based on an integration of a global finite element analysis of the diskblade assembly.
Hills i mechanics of fretting fatigue 1 under these conditions, modelling of the final phase of the initiation process will be even more difficult, as the crack exists in an anisotropic material, and the influence of nearby grain boundaries or crystallographic orientation will still be profound, but difficult to quantify. K should be considered because most fretting fatigue cracks incline under multiaxial stress fields caused by the contact pressure and tangential force lamacq et al. It leads to fretting damage, which reduces the service life of the bodies in contact. Fretting fatigue life estimation using fatigue damage. Influence of fretting on flexural fatigue of 304 stainless. This can be explained by the high stresses generated at the contact surface between the two bodies. Some considerations on the mitigation of fretting damage. In the developed method, fatigue damage value at the cracking location is corrected with fatigue damage gradient and the corrected value is compared directly with the plain fatigue data for life estimation. The fretting is responsible for many failures of components in the industry. Pdf fretting fatigue experiment and analysis of alsi9cu2mg alloy.
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