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.

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.

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.

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.

Finite element analysis of the effects of load amplitude and phase on crack initiation location in fretting fatigue

2021 ◽  
pp. 095440622110095
Author(s):  
Ling Li ◽  
Ziming Wei ◽  
Dong Zhang ◽  
Jingjing Wang ◽  
Xiaohui Shi
Keyword(s):  
Fatigue Crack ◽  
Phase Difference ◽  
Numerical Models ◽  
Fatigue Cracks ◽  
Fretting Fatigue ◽  
Trailing Edge ◽  
Element Analysis ◽  
Load Amplitude ◽  
Fretting Damage ◽  
Phase Differences

Fretting fatigue is a major form of fretting damage affected by various factors. In this paper, the Ruiz parameter is used to predict the variation in the initiation location of the fretting fatigue crack with the amplitude of load, providing a reference for the study of the initiation characteristics of fretting fatigue cracks. The influence of the phase difference between loads is also considered. Three numerical models are established using ABAQUS for simulation experiments. Four phase difference angles are involved, i.e. 0°, 90°, 180° and 270°. Results indicate that for 0° phase difference, the maximum of initiation parameter K is always observed at the trailing edge of the contact zone (near the loading side of the strain load) with the increase of load amplitude, such that the fretting fatigue crack initiates at the trailing edge. However, for 90°, 180°, and 270° phase differences, the maximum of initiation parameter K shifts from one edge of the contact to the other with the increase of load amplitude. In addition, it is observed that the maximum and minimum initiation parameter K values are obtained for 0° and 180° phase differences, respectively, while the values of K for 90° and 270° phase differences are approximately equal and between those for 0° and 180°.

Guided Wave Acoustic Emission from Fatigue Crack Growth in Aluminium Plate

2006 ◽  
Vol 13-14 ◽  
pp. 23-28 ◽  
Author(s):  
C.K. Lee ◽  
Jonathan J. Scholey ◽  
Paul D. Wilcox ◽  
M.R. Wisnom ◽  
Michael I. Friswell ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Elastic Waves ◽  
Fatigue Cracks ◽  
Guided Wave ◽  
Experimental Results ◽  
Multiple Reflections ◽  
Alloy Plate

Acoustic emission (AE) testing is an increasingly popular technique used for nondestructive evaluation (NDE). It has been used to detect and locate defects such as fatigue cracks in real structures. The monitoring of fatigue cracks in plate-like structures is critical for aerospace industries. Much research has been conducted to characterize and provide quantitative understanding of the source of emission on small specimens. It is difficult to extend these results to real structures as most of the experiments are restricted by the geometric effects from the specimens. The aim of this work is to provide a characterization of elastic waves emanating from fatigue cracks in plate-like structures. Fatigue crack growth is initiated in large 6082 T6 aluminium alloy plate specimens subjected to fatigue loading in the laboratory. A large specimen is utilized to eliminate multiple reflections from edges. The signals were recorded using both resonant and nonresonant transducers attached to the surface of the alloy specimens. The distances between the damage feature and sensors are located far enough apart in order to obtain good separation of guided-wave modes. Large numbers of AE signals are detected with active fatigue crack propagation during the experiment. Analysis of experimental results from multiple crack growth events are used to characterize the elastic waves. Experimental results are compared with finite element predictions to examine the mechanism of AE generation at the crack tip.

Plastic Slip and Early Stage of Fatigue Damage in Polycrystals: Comparison between Experiments and Crystal Plasticity Finite Elements Simulations

2014 ◽  
Vol 891-892 ◽  
pp. 1711-1716 ◽  
Author(s):  
Loic Signor ◽  
Emmanuel Lacoste ◽  
Patrick Villechaise ◽  
Thomas Ghidossi ◽  
Stephan Courtin
Keyword(s):  
Fatigue Crack ◽  
Finite Elements ◽  
Crack Initiation ◽  
Fatigue Damage ◽  
Crystal Plasticity ◽  
Early Stage ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Plastic Slip

For conventional materials with solid solution, fatigue damage is often related to microplasticity and is largely sensitive to microstructure at different scales concerning dislocations, grains and textures. The present study focuses on slip bands activity and fatigue crack initiation with special attention on the influence of the size, the morphology and the crystal orientation of grains and their neighbours. The local configurations which favour - or prevent - crack initiation are not completely identified. In this work, the identification and the analysis of several crack initiation sites are performed using Scanning Electron Microscopy and Electron Back-Scattered Diffraction. Crystal plasticity finite elements simulation is employed to evaluate local microplasticity at the scale of the grains. One of the originality of this work is the creation of 3D meshes of polycrystalline aggregates corresponding to zones where fatigue cracks have been observed. 3D data obtained by serial-sectioning are used to reconstruct actual microstructure. The role of the plastic slip activity as a driving force for fatigue crack initiation is discussed according to the comparison between experimental observations and simulations. The approach is applied to 316L type austenitic stainless steels under low-cycle fatigue loading.

scholarly journals Structural and mechanical defects of materials of offshore and onshore main gas pipelines after long-term operation

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Pavlo Maruschak ◽  
Sergey Panin ◽  
Iryna Danyliuk ◽  
Lyubomyr Poberezhnyi ◽  
Taras Pyrig ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Quantitative Analysis ◽  
Stress Concentration ◽  
Cyclic Loading ◽  
Fatigue Cracks ◽  
Preliminary Deformation ◽  
Term Operation ◽  
Steel Pipes

AbstractThe study has established the main regularities of a fatigue failure of offshore gas steel pipes installed using S-lay and J-lay methods.We have numerically analyzed the influence of preliminary deformation on the fatigue life of 09Mn2Si steel at different amplitudes of cyclic loading. The results have revealed the regularities of formation and development of a fatigue crack in 17Mn1Si steel after 40 years of underground operation. The quantitative analysis describes the regularities of occurrence and growth of fatigue cracks in the presence of a stress concentration.

The Effect of Discontinuity Size on the Initiation of Shattered Rim Defects

2000 ◽  
Author(s):  
Daniel H. Stone ◽  
Geoffrey E. Dahlman
Keyword(s):  
Fatigue Crack ◽  
Mixed Mode ◽  
Crack Surface ◽  
Fatigue Cracks ◽  
Rolling Direction ◽  
Mixed Mode Fracture ◽  
Mode Fracture ◽  
Clam Shell ◽  
Shear Component ◽  
Mechanics Analysis

Abstract Shattered rim defects are the result of large fatigue cracks that propagate roughly parallel to the wheel tread surface. They form and grow 12 to 20 millimeters (1/2 to 3/4 in.) below the tread surface. A typical shattered rim is shown in Figure 1. The clamshell pattern of the fracture surface is also typical of shattered rims. The clamshell pattern is formed because fatigue cracks at this depth in wheels have a shear component and, when the rolling direction is opposite, the cracks grow in a different direction forming a series of ridges and valleys. Miezoso, et alia have presented a mixed mode fracture mechanics analysis of the process of forming a clam-shell fatigue crack surface in wheels.

The Influence of Biaxial Mean Stresses on the Failure of Tubes by Fatigue

1961 ◽  
Vol 12 (1) ◽  
pp. 1-33 ◽  
Author(s):  
H. L. Cox ◽  
N. B. Owen
Keyword(s):  
Fatigue Crack ◽  
Mild Steel ◽  
Test Piece ◽  
Fatigue Cracks ◽  
Small Diameter ◽  
Axial Direction ◽  
Gas Pressure ◽  
Modes Of Failure ◽  
Explosive Failure ◽  
Bending Stresses

SummaryThin-walled tubes, in. in diameter, of three hard aluminium alloys and of mild steel have been tested in fatigue under three systems of alternating stresses while subjected to biaxial mean tensions imposed by means of internal pressure. In fatigue under direct or bending stresses the hoop tension in the walls of the aluminium alloy tubes did not seriously reduce the fatigue endurance, but it did markedly affect the mode and rate of crack propagation; cracks initially transverse to the tube axis tended to develop very rapidly in the axial direction. This tendency was present under both fluid and gas pressure, and under gas pressure the cracks propagated so fast that the test piece was often blown to pieces before the gas pressure fell by leakage through the cracks. The gradual taper in wall thickness along the fillets joining the test section to the enlarged ends offered no barrier to propagation of the axial cracks and the whole test piece, including its enlarged ends, was often shattered. Propagation of the axial cracks was preventible by sufficiently reducing the fillet radius, or by a ring glued on. Under alternating torsion, both endurance and mode of failure were affected by internal gas pressure. The initial fatigue crack, either circumferential or axial, often extended over a length comparable with the diameter of the tube, except under low ranges of shear stress when the crack length was sometimes very short. At each end the cracks forked in a characteristic manner and under moderate gas pressure the portions of tHe wall between the prongs of the fork were blown outwards. Under high pressure explosive failure and fragmentation often occurred. Mild steel under alternating torsion with internal gas pressure exhibited the same modes of failure, and two or more fatigue cracks were often formed simultaneously. Under high hoop tension, cracks propagated rapidly and one test piece, after two million cycles endurance, failed by exploding. However, no mild steel test piece was fragmented. A tentative explanation is offered of the reason why, in tubes of small diameter, rather short fatigue cracks may be expected to lead to fast fracture under the static loading. Attention is drawn to the inference that the initial fatigue crack itself must develop very quickly to considerable length.

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