scholarly journals EFFECT OF THE RIVET-HOLE TOLERANCE ON THE STRESS-SEVERITY FACTOR

2021 ◽  
Vol 55 (2) ◽  
pp. 237-242
Author(s):  
Jiří Běhal ◽  
Roman Růžek
Keyword(s):  
Fatigue Life ◽  
Load Transfer ◽  
Research Centre ◽  
Hole Filling ◽  
Molybdenum Disulphide ◽  
Severity Factor ◽  
Transfer Factors ◽  
Riveted Joints ◽  
Riveted Joint ◽  
Initial Clearance

This work is focused on a quantitative procedure for estimating the generally unfavourable effects that incorrectly drilled holes, characterized by the initial clearance between a rivet and a hole, have on the fatigue life of riveted joints. The solution is based on an analytical approach using the stress-severity-factor concept. An experimental programme with riveted-joint specimens characterized by low-load transfer factors was realized in the Czech Aerospace Research Centre (VZLU) test lab under constant amplitude loading. The holes for rivet joints with 4-mm diameters were prepared with the clearance in a range of 0.0–0.16 mm. Force-controlled riveting was applied using a constant pressure force to form the driven head. To prevent fretting events between the joined parts, their anodized contact surfaces were lubricated with MOLYKA, plastic grease with molybdenum disulphide and graphite. The experimental data showed that the load-transfer factor and the fatigue life depend on the initial clearance between a rivet and a hole. The presented procedure introduced the hole-filling factor, integrated in the stress-severity-factor concept as a function of the initial clearance between a rivet and a hole.

Applicability of Empirical Formulae for the Fatigue Notch Factor to Estimate Riveted Lap Joint Fatigue Strength

2014 ◽  
Vol 224 ◽  
pp. 81-86
Author(s):  
Tomasz Machniewicz ◽  
Małgorzata Skorupa ◽  
Andrzej Skorupa ◽  
Adam Korbel
Keyword(s):  
Fatigue Life ◽  
Load Transfer ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Lap Joints ◽  
Riveted Joints ◽  
Riveted Joint ◽  
Fatigue Notch Factor ◽  
Riveted Lap Joints ◽  
Semi Empirical

A semi-empirical fatigue life prediction model under development by the present authors for riveted lap joints used in aircraft structures is outlined. In contrast to existing models, it will account for the influence of the rivet squeeze force on the fatigue life of riveted joints. To determine the effect of rivet-hole interference on the fatigue behaviour of a riveted joint, a series of fatigue tests on filled hole coupons with different amounts of interference will be carried out under loading conditions representing the bypass load, transfer load and secondary bending. These experiments will allow evaluating of the dependency of the fatigue notch factors on rivet hole expansion. Preliminary results obtained so far are presented in this paper.

Modified Stress Severity Factor Method Based on 3D-FEM

2014 ◽  
Vol 945-949 ◽  
pp. 1150-1154
Author(s):  
Xiao Hua Yang ◽  
Xue Jun Liu ◽  
Zhao Hu
Keyword(s):  
Fatigue Life ◽  
Stress State ◽  
Experimental Result ◽  
3D Fem ◽  
Severity Factor ◽  
Factor Method ◽  
D Model

The traditional stress severity factor (SSF) approach was applied to analyze the life of aircraft multi-fastener joint. 3-D model was established under simulated state of practical assembling using CATIA, and then the model was imported into ABAQUS to analyze the detail stress state of aircraft multi-fastener joint. The life of aircraft multi-fastener joint was estimated by amending the SSF method. The example shows that the fatigue life by the approach is closer to the experimental result.

Improving Fatigue Life of Riveted Joints by Rivet Hole Sizing

2014 ◽  
Vol 598 ◽  
pp. 141-146
Author(s):  
Adam Lipski ◽  
Zbigniew Lis
Keyword(s):  
Fatigue Life ◽  
Fold Increase ◽  
Fatigue Tests ◽  
Aviation Industry ◽  
Lap Joint ◽  
Riveted Joints ◽  
Riveting Process ◽  
The Difference ◽  
Structural Connection ◽  
The Impact

The aim of this paper is to assess the impact of the rivet hole sizing process on the fatigue life based on the example of the structural connections characteristic for riveted joints used in aviation industry. Test specimens reflected the structural connection consisting in a riveted lap joint of an airplane plating stiffened with a T-bar. Connected plates and the T-bar are made of D16CzATW aluminum alloy. 3 mm diameter oval head solid rivets for aviation-related purposes were made of PA24 aluminum. During fatigue tests, individual specimens with non-sized holes and with sized holes were subjected to uniaxial, one-sided, fixed-amplitude loading (R = 0). It can be concluded from the fatigue life comparison that introduction of an additional operation in the riveting process, i.e. the hole sizing, results in significant, about two-fold increase of the fatigue life of the riveted structural connection, even at slight sizing degree. The difference of the specimen damage nature was observed between specimens with sized and non-sized holes.

scholarly journals Fatigue Life Enhancement of Welded Steel-Steel Composite during Crack Growth from Weak to Strong Steel: An Experimental Validation

2009 ◽  
Vol 417-418 ◽  
pp. 825-828
Author(s):  
Sunil Bhat ◽  
Vijay G. Ukadgaonker
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Load Transfer ◽  
Electron Beam Welding ◽  
Fatigue Testing ◽  
Crack Tip ◽  
Compact Tension ◽  
Welded Steel ◽  
Maraging Steels ◽  
Bimetallic Composite

Strength mismatch effect across weld interfaces, generated by welding weak and strong steels, influences fatigue and fracture properties of a welded bimetallic composite. Advancing fatigue crack tip in weak parent steel is shielded from the remote load when it reaches near the interface of ultra strong weld steel. Entry of crack tip plasticity into weld steel induces load transfer towards weld which dips crack growth rates thereby enhancing the fatigue life of the composite. A computational model for fatigue life prediction of strength mismatched welded composite under K dominant conditions is validated by experimental work in this paper. Notched bimetallic compact tension specimens, prepared by electron beam welding of weak alloy and strong maraging steels, are subjected to fatigue testing in high cycle regime.

Determination of the Creep Deflection of a Rivet in Double Shear

1959 ◽  
Vol 26 (2) ◽  
pp. 285-290
Author(s):  
Joseph Marin
Keyword(s):  
Theoretical Prediction ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Structural Components ◽  
Double Shear ◽  
Riveted Joints ◽  
Simple Tension ◽  
Riveted Joint ◽  
Jet Power

Abstract Structural components of modern aircraft are subjected to elevated temperatures by jet power plants and by skin friction resulting from supersonic speeds. Some of these high-temperature-aircraft structural components are riveted connections. Considerable experimental data are available on the creep of riveted connections used in aircraft [1]. However, a survey of the literature shows a lack of results on the theoretical prediction of creep in riveted connections from the usual creep and creep-rupture data for simple tension. The creep of a riveted joint is dependent on various factors including rivet diameter, rivet lengths, and plate thicknesses. This influence of size means that each particular riveted joint must be tested to obtain the necessary information. A basic approach to the problem is theoretically to predict the creep behavior of riveted joints from creep in simple tension. One of the important parts of the creep deformation of a riveted connection, Fig. 1(a), is the creep of the rivet. This paper deals with an approximate theoretical prediction of the creep deflection in a rivet based upon the creep constants of the material in simple tension.

Fatigue Life Estimation of Aeronautical Joints Based on Stress Severity Factor

2016 ◽  
Vol 1135 ◽  
pp. 128-139
Author(s):  
Roberto da Silva Gonçalves ◽  
Carlos E. Chaves
Keyword(s):  
Fatigue Life ◽  
Fatigue Tests ◽  
Lap Joints ◽  
Severity Factor ◽  
Application Range ◽  
Aircraft Fuselage ◽  
Bending Effect ◽  
Fatigue Life Estimation ◽  
Recorded Data ◽  
Almost All

The goal of the present work is to investigate the validity limits and safe application range of Stress Severity Factor methodology in estimating fatigue life of aircraft fuselage joints. Fatigue tests were conducted and recorded data from aluminum alloys joints was subjected to analytical evaluation. FE models were created to obtain fasteners load distribution and determine normal stress due to secondary bending. Severity Factor method conservatively estimated fatigue life of 74% for the analyzed joints. Its robustness was verified for lap joints fatigue life estimative, but for almost all single strap joints, secondary bending effect were significant. Thus for this kind of joints, a term accounting for bending stress was added to the original severity factor formulation to increase level of safety in fatigue life estimates.

Methods to Increase the Fatigue Life of Friction Stir Lap Welds in No-load Transfer Coupons Using a Retractable Pin Tool

2012 ◽  
Vol 9 (5) ◽  
pp. 103899 ◽  
Author(s):  
Farzad Baratzadeh ◽  
Christian A. Widener ◽  
Hamid M. Lankarani ◽  
Dwight A. Burford
Keyword(s):  
Fatigue Life ◽  
Load Transfer ◽  
Friction Stir

scholarly journals The Analysis of the Influence of Riveting Parameters Specified in Selected Riveting Instructions on Residual Stresses

2014 ◽  
Vol 2014 (6) ◽  
pp. 63-71
Author(s):  
Wojciech Wronicz ◽  
Jerzy Kaniowski
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Numerical Simulations ◽  
Western Europe ◽  
Point Of View ◽  
Industry Standards ◽  
Riveted Joints ◽  
Aerospace Companies ◽  
The Impact

Abstract The riveting parameters strongly affect residual stresses induced during riveting, which in turn have an impact on the fatigue life of riveted joints. Since rivets are established as critical from the fatigue point of view, the fatigue life of riveted joints often determines the life of the whole structure. The authors were able to become acquainted with three riveting instructions (process specifications) used by the aerospace companies from western Europe. This work presents the analysis of the riveting parameters' influence on residual stresses around the rivets. The impact of the clearance between a rivet shank and a hole as well as driven head dimensions and a rivet length were investigated based on the numerical simulations. The aim of the analysis was to determine the range of stresses variation when the requirements of the riveting instructions are fulfilled. For the purposes of comparison, the calculations were performed also with the parameters as specified in the Polish industry standards. For all calculations, the geometry of the universal rivet MS20470 was used. The results show that residual stresses can vary strongly depending on the parameters in the instructions and standard requirements.

Riveted Hull Joint Design in RMS Titanic and Other Pre—World War I Ships

2003 ◽  
Vol 40 (02) ◽  
pp. 82-92
Author(s):  
Richard Woytowich
Keyword(s):  
Finite Element ◽  
World War I ◽  
Finite Element Model ◽  
Plate Thickness ◽  
Element Model ◽  
World War ◽  
Joint Construction ◽  
Riveted Joints ◽  
Riveted Joint ◽  
Out Of Plane

Beginning with an overview of riveted joint construction, this paper shows that the efficiency of riveted joints in pre-World War I ships decreased as plate thickness increased. In the case of the RMS Titanic, some of the joints involved in the iceberg impact were only about 27% as strong as the plates they connected. A finite element model is used to show how such a joint would respond to the sort of out-of-plane load that the iceberg would have applied. For one possible load configuration, the joint failure is recreated. Finally, although Titanic and her sisters were not built to class, the design of the riveted joints is examined in the context of relevant Lloyd's Register of Shipping Rules.

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