The Effect of Friction Coefficient on Fretting Fatigue Cracks

2013 ◽  
Vol 690-693 ◽  
pp. 2008-2011
Author(s):  
Tao Guo ◽  
Liang Wu ◽  
Xiao Nan Liu ◽  
Ran Guo
Keyword(s):  
Fatigue Crack ◽  
Friction Coefficient ◽  
Crack Formation ◽  
Fatigue Cracks ◽  
Outer Boundary ◽  
Fatigue Loading ◽  
Fretting Fatigue ◽  
Hole Edge ◽  
Mechanics Characteristic ◽  
Paper Work

The riveting is widely used for fitting together two or more components of structure in the same or different materials. And mechanics characteristic is very complex. The paper work focus on study fretting fatigue crack formation with different friction coefficient and fatigue loading, by analyzing the stress field of upper hole edge and outer boundary of contact area. And comparing with the experimental, founding the risk point of single bolt riveted aluminum components.

Estimation of the Shape Evolution and the Growth History of an Embedded Crack by Fatigue Loading

2011 ◽  
Author(s):  
Koji Gotoh ◽  
Keisuke Harada ◽  
Yosuke Anai
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Estimation Method ◽  
Estimation Procedure ◽  
Fatigue Loading ◽  
Shape Evolution ◽  
Crack Growth Behaviour ◽  
Embedded Crack

Fatigue life estimation for planar cracks, e.g. part-through surface cracks or embedded cracks is very important because most of fatigue cracks found in welded built-up structures show planar crack morphologies. Fatigue crack growth behaviour of an embedded crack in welded joints is investigated in this study. The estimation procedure of crack shape evolution for an embedded crack is introduced and validation of the estimation procedure of fatigue crack growth based on the numerical simulation of fatigue crack growth with EDS concept for an embedded crack is performed. The validity of the proposed shape evolution estimation method and the fatigue crack growth simulation based on the fracture mechanics approach with EDS concept are confirmed.

scholarly journals Experimental and Numerical Investigations of Fretting Fatigue Behavior for Steel Q235 Single-Lap Bolted Joints

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yazhou Xu ◽  
Zhen Sun ◽  
Yuqing Zhang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Initiation ◽  
Failure Mode ◽  
Contact Stress ◽  
Fatigue Cracks ◽  
Fretting Fatigue ◽  
Bolted Joints ◽  
Normal Contact Stress ◽  
Normal Contact

This work aims to investigate the fretting fatigue life and failure mode of steel Q235B plates in single-lap bolted joints. Ten specimens were prepared and tested to fit theS-Ncurve. SEM (scanning electron microscope) was then employed to observe fatigue crack surfaces and identify crack initiation, crack propagation, and transient fracture zones. Moreover, a FEM model was established to simulate the stress and displacement fields. The normal contact stress, tangential contact stress, and relative slipping displacement at the critical fretting zone were used to calculate FFD values and assess fretting fatigue crack initiation sites, which were in good agreement with SEM observations. Experimental results confirmed the fretting fatigue failure mode for these specimens. It was found that the crack initiation resulted from wear regions at the contact surfaces between plates, and fretting fatigue cracks occurred at a certain distance away from hole edges. The proposed FFD-Nrelationship is an alternative approach to evaluate fretting fatigue life of steel plates in bolted joints.

Designing against fretting fatigue: Crack self-arrest

1998 ◽  
Vol 33 (1) ◽  
pp. 17-25 ◽  
Author(s):  
R Moobola ◽  
D A Hills ◽  
D Nowell
Keyword(s):  
Fatigue Crack ◽  
Fatigue Cracks ◽  
Fretting Fatigue ◽  
Flaw Size

Issues concerned with self-arrest of fretting fatigue cracks at small initial lengths are discussed for a range of well-defined contact geometries. The conditions under which self-arrest will occur are given, together with the maximum tolerable initial flaw size, beyond which self-arrest may not be anticipated.

Study of Fretting Fatigue Crack Initiation For Riveted Al 6xxx Components

2008 ◽  
Vol 33-37 ◽  
pp. 243-248
Author(s):  
Ran Guo ◽  
En Qiang Lin ◽  
Rui Chun Duan ◽  
Gerard Mesmacque ◽  
Abdelwaheb Amrouche
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Material Properties ◽  
Crack Formation ◽  
Fatigue Crack Initiation ◽  
Fretting Fatigue ◽  
Contact Friction ◽  
Strain Gauges ◽  
Finite Element Models

Riveting is a procedure widely used for fitting together two or more elements of a structure, that could be of the same or different material. In these assemblies the stress field is complex and a number of parameters, including effect of the geometrical discontinuities, contact between elements, tightening, material properties and applied load must be considered. The current work focuses on the study of fretting fatigue crack formation in common 6XXX aluminum alloys, used in land transportation equipments, and the determination of the characteristic crack initiation sites by means of both experimental and numerical methods. 3D finite element models were validated by the experimental results obtained with strain gauges. The influence of the contact friction coefficient at the fretting surface and fastening forces on the initiation of cracks, are discussed by the comparison of the different numerical results.

Mechanics of fretting fatigue crack formation

Wear ◽  
1996 ◽  
Vol 198 (1-2) ◽  
pp. 93-107 ◽  
Author(s):  
Matthew P. Szolwinski ◽  
Thomas N. Farris
Keyword(s):  
Fatigue Crack ◽  
Crack Formation ◽  
Fretting Fatigue

scholarly journals Acoustic Emission Monitoring of Fatigue Crack Growth in Mooring Chains

2019 ◽  
Vol 9 (11) ◽  
pp. 2187 ◽  
Author(s):  
Ángela Angulo ◽  
Jialin Tang ◽  
Ali Khadimallah ◽  
Slim Soua ◽  
Cristinel Mares ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Large Scale ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Damage Initiation ◽  
High Level

Offshore installations are subject to perpetual fatigue loading and are usually very hard to inspect. Close visual inspection from the turret is usually too hazardous for divers and is not possible with remotely operated vehicles (ROVs) because of the limited access. Conventional nondestructive techniques (NDTs) have been used in the past to carry out inspections of mooring chains, floating production storage and offloading systems (FPSOs), and other platforms. Although these have been successful at detecting and assessing fatigue cracks, the hazardous nature of the operations calls for remote techniques that could be applied continuously to identify damage initiation and progress. The aim of the present work is to study the capabilities of acoustic emission (AE) as a monitoring tool to detect fatigue crack initiation and propagation in mooring chains. A 72-day large-scale experiment was designed for this purpose. A detailed analysis of the different AE signal time domain features was not conclusive, possibly due to the high level of noise. However, the frequency content of the AE signals offers a promising indication of fatigue crack growth.

Evaluation of the fretting fatigue behaviour of commercially pure titanium

2007 ◽  
Vol 221 (3) ◽  
pp. 143-150 ◽  
Author(s):  
C A R P Baptista ◽  
L S Rossino ◽  
M A S Torres ◽  
C Y Shigue
Keyword(s):  
Fatigue Crack ◽  
Fatigue Cracks ◽  
Testing Machine ◽  
Pure Titanium ◽  
Surface Damage ◽  
Fatigue Behaviour ◽  
Fretting Fatigue ◽  
Cyclic Stress ◽  
Commercially Pure Titanium ◽  
Commercially Pure

Fretting fatigue occurs when the contact surfaces of two components undergo small oscillatory movement while they are subjected to a clamping force. A cyclic external load gives rise to the early initiation of fatigue cracks, thus reducing their service life. In this paper, the fretting fatigue behaviour of commercially pure titanium flat samples (1.5mm thick) is evaluated. A fretting device composed of a frame, load cell, and two screw-mounted cylindrical fretting pads with convex extremities was built and set to a servo-hydraulic testing machine. The fatigue tests were conducted under load control at a frequency of 10 Hz and stress ratio R = 0.1, with various contact load values applied to the fretting pads. Additional tests under inert environment allowed assessing the role of oxidation on the wear debris formation. The fracture surfaces and fretting scars were analysed via scanning electron microscopy in order to evaluate the surface damage evolution and its effect on the fatigue crack features. The effect of the fretting condition on the S-N curve of the material in the range of 104-106 cycles is described. Fatigue crack growth calculations allowed estimating the crack initiation and propagation lives under fretting conditions. The effect of the fretting condition in fatigue life is stronger for the lower values of cyclic stress and does not seem to depend on the contact loading value.

scholarly journals A Probabilistic Approach to Small Fatigue Crack Initiation and Sizing Using Acoustic Emission

2017 ◽  
Author(s):  
Azadeh Keshtgar ◽  
Mohammad Modarres
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Crack Initiation ◽  
Health Management ◽  
Fatigue Cracks ◽  
Probabilistic Approach ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Accurate Estimation ◽  
Small Fatigue Crack

One of the major concerns in structural health management (SHM) is the early detection of a growing crack. Using this, future damage due to crack propagation can be mitigated or eliminated by implementing proper repair and maintenance. Acoustic Emission (AE) is a non-destructive testing (NDT) method with potential applications for locating and monitoring fatigue cracks. The research presented in this paper focuses on SHM using AE. A novel AE signal analysis approach was proposed in order to detect crack initiation and assess small crack lengths. Experimental investigation indicated that initiation of a crack could be identified through the statistical analysis of the resulting features of the AE signals. A probabilistic AE-based model for small fatigue crack sizing was developed and the uncertainties of the model were estimated. In addition, a probabilistic model validation approach was implemented to confirm accurate estimation of the results. The outcome of this research can be used to evaluate the integrity of structures under fatigue loading. The proposed approach can also be applied as an approach to manage health and assess prognosis of structures.

Fatigue Crack Growth of Glass Fiber Reinforced Aluminum Alloy Laminate (Al/GFRP) According to the Micro Hole Location

2007 ◽  
Vol 345-346 ◽  
pp. 693-696 ◽  
Author(s):  
Cheol Woong Kim ◽  
Dong Joon Oh ◽  
Kee Joo Kim ◽  
Ki Weon Kang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Propagation ◽  
Crack Length ◽  
Fatigue Cracks ◽  
High Strength ◽  
Fatigue Loading ◽  
Artificial Defect ◽  
Circular Holes ◽  
Micro Hole

The diverse studies on Al/GFRP laminates with the circular holes, therefore, have been carried out recently. The recent studies just focused on the behavior of the fatigue crack propagation and the delamination when the shape and the size of the notches were changed. Therefore, this study evaluated the location effect of the defects in the vicinity of the circular notch of the high strength monolithic aluminum and Al/GFRP laminates on the initiation life (Ni) of the fatigue cracks, the relationship between the crack length (a) and the fatigue life (N). In addition, the fatigue crack behavior of Al/GFRP laminates was studied when the fatigue loading and the interlaminar delamination took place at the same time during crack propagation. In conclusions, (1) for the monolithic aluminum, 10% of the failure life at θ2=30° was more increased than that at θ3=60°. (2) The crack length and the fatigue life behavior of Al/GFRP laminates according to the location of the artificial defect were different from those of the monolithic aluminum. Namely, the fatigue life of θ1=0° and θ2=30° were remarkably shorter than those of θ3=60° and θ4=90°.

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