Influence of Interference and Clamping on Fretting Fatigue in Single Rivet-Row Lap Joints

2000 ◽  
Vol 123 (4) ◽  
pp. 686-698 ◽  
Author(s):  
K. Iyer ◽  
C. A. Rubin ◽  
G. T. Hahn

Primary fretting fatigue variables such as contact pressure, slip amplitude and bulk cyclic stresses, at and near the contact interface between the rivet shank and panel hole in a single rivet-row, 7075-T6 aluminum alloy lap joint are presented. Three-dimensional finite element analysis is applied to evaluate these and the effects of interference and clamping stresses on the values of the primary variables and other overall measures of fretting damage. Two rivet geometries, non-countersunk and countersunk, are considered. Comparison with previous evaluations of the fretting conditions in similar but two-dimensional connections indicates that out-of-plane movements and attending effects can have a significant impact on the fatigue life of riveted connections. Variations of the cyclic stress range and other proponents of crack initiation are found to peak at distinct locations along the hole-shank interface, making it possible to predict crack initiation locations and design for extended life.

1999 ◽  
Author(s):  
K. Iyer ◽  
C. A. Rubin ◽  
G. T. Hahn

Abstract Three-dimensional finite element analyses (FEA) of an elastic, single rivet-row, aluminum alloy lap joint are presented. The effects of rivet geometry (countersinking), rivet material and interfacial friction coefficient are examined. Interference and lateral clamping are not treated. Panels loaded in tension with vacant, tapered holes are also examined. Load transfer through the joint, the joint compliance, rivet-tilt, the local slips at rivet-panel and panel-panel interfaces, contact pressures and local stresses are evaluated. Relations between these features and the contact and bending driven stress concentration are clarified. The work shows that the stress concentration factor, rivet-panel slips, peak stresses, contact pressures and rivet deformation are all related, and increase with the severity of the countersink. Panel bending, rivet tilt and countersinking introduce large, out-of-plane stress gradients and shift the peak stresses to the interior surface of the countersunk panel. The results demonstrate the importance of out-of-plane distortions in accounting for the behavior of the riveted lap joints. Three opportunities are identified for improving lap joint performance without increasing the weight.


2001 ◽  
Author(s):  
K. Iyer ◽  
C. A. Rubin ◽  
G. T. Hahn

Abstract Three-dimensional finite element analysis of an elastic, double rivet-row, aluminum alloy lap joint with non-countersunk aluminum rivets, is presented. The compliance of the connection, rivet tilt, peak contact pressures and slip amplitudes, in the absence of interference and clamp-up, are described. Rivet-panel slips in the double-row assembly are between 50–60% of those calculated for the single-row case. Contrary to the expectation that the second row of rivets might reduce the stress concentration factor by half, the additional row of rivets provides a reduction of only 28%.


2003 ◽  
Vol 12 (2) ◽  
pp. 096369350301200
Author(s):  
George J Tsamasphyros ◽  
George N Kanderakis ◽  
Nikos K Furnarakis ◽  
Zaira P Marioli-Riga

A host of one and two-sided composite patch reinforcements of metallic structures with different patch thickness were considered, in order to compare two-dimensional finite element analysis using shell laminate elements with three-dimensional finite element analysis. In order to verify the accuracy of this approach a parametric study has been performed and the 2D results were compared to the outcome of the corresponding three-dimensional finite element analysis, which accuracy has been experimentally verified in previous works. It was found that for the case of two-sided reinforcement the results obtained by the two methods were in very good agreement. For the case of one-sided reinforcement some deviation of the results of two-dimensional analysis has been observed, which was due to the tendency of the structure for out-of-plane bending, resulting from the bonding of a reinforcing patch to only one face of the structure. According to the results of this parametric study and since most aircraft structures are constrained against local out-of-plane bending (e.g. aircraft skins through stringers) two-dimensional finite elements analysis using shell laminate elements is proposed as an accurate and easy to use analysis tool for the design of both one and two-sided composite patch repairs of relatively simple structures.


2001 ◽  
Author(s):  
K. Iyer ◽  
C. A. Rubin ◽  
G. T. Hahn

Abstract Three-dimensional finite element analysis of an elastic, double rivet-row, aluminum alloy lap joint with countersunk, aluminum and steel rivets, is presented. Relations between the connection compliance, rivet deformation, peak contact pressures and slip amplitudes, in the absence of interference and clamp-up, are described. Analysis of a connection with non-countersunk rivets is presented in a companion paper. The trends seen in the results are similar to those obtained with non-countersunk rivets, although the peak stress concentrations in the present case are much higher. A superposition approach for estimating stress concentration factors in the panels of multi-row riveted connections with standard or countersunk rivets is presented.


2011 ◽  
Vol 66-68 ◽  
pp. 1090-1093 ◽  
Author(s):  
Guang Xue Yang ◽  
Qiang Li ◽  
Ji Long Xie

In this paper, aimed at wheel-axle with axle load of 30 ton, the three dimensional finite element model was established, and the interference fit between wheel and axle was considered. According to Standard EN13103, the vertical load and the lateral load were determined, and then the stress distribution of axle was computed under two cases: only vertical load and both vertical and lateral load. The result shows that: the increase of axle load causes the increase of slip between axle and hub, which leads to an increase of fretting damage and a reduction in fatigue life. In addition, Dang Van criterion was employed to evaluate the fatigue of the whole axle. It is found that the transition zone next to wheel seat and the interface of hub and axle are dangerous points, which is in accordance with the practice.


Author(s):  
K. Iyer ◽  
F. L. Brittman ◽  
S. J. Hu ◽  
P. C. Wang ◽  
D. B. Hayden ◽  
...  

The fatigue life and fretting characteristics of aluminum alloy 5754-O self-piercing riveted lap joints have been investigated experimentally and analytically. The experimental program involves a set of 27 cyclic tension tests on three different joints consisting of either 1 mm, 2 mm or 3 mm-thick sheet specimens. In most cases (85%), fatigue cracks are found to initiate on the faying surface of the upper sheet, adjacent to the hole, and at an angular location that lies on the sheet loading axis towards the loading end. Three-dimensional finite element analysis of the three joints has also been performed. Computed distributions of local stresses and rivet-sheet slips are interpreted in terms of experimental observations of fatigue life, crack initiation location and fretting damage observations. Significantly, the calculations provide a rationale for the surprising crack initiation location.


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