New method and tool for increasing fatigue life of a large number of small fastener holes in 2024-T3 Al alloy

  • J. T. MaximovEmail author
  • G. V. Duncheva
  • A. P. Anchev
  • I. M. Amudjev
Technical Paper


A new method and tool for processing a large number of small fastener holes in high-strength Al alloy structures through cold plastic deformation have been developed in order to decrease labor and operational time by following the high fatigue resistance requirement. The deforming portion of the tool has been specifically profiled in cross section so that the contact with the hole surface is disrupted. The diameter of the circumference around the deforming portion is greater than the diameter of a preliminary drilled and reamed hole. The tool and hole have a common axis around which the tool is rotating and, at the same time, moving along the same axis while passing through the hole. Thus, this method produces three main beneficial effects: hole cold expansion, surface plastic deformation (mixed burnishing) and microstructure modification (friction stir and torsion). These three effects have been studied and proven through an experiment and 3D FEM simulations. An integral evaluation of the proposed method and tool has been made through fatigue tests of cyclic tension. The obtained S–N curves prove that the fatigue life increases significantly in comparison with the case of only drilled and reamed holes. Based on the conducted studies, a super-combined tool that consequently performs drilling, reaming and cold plastic deformation has been designed and manufactured. This tool significantly increases the productivity of processing a large number of fastener holes in aluminum structures.


2024-T3 Al alloy Fatigue life enhancement Hole cold expansion Surface plastic deformation Cyclic tensile test FEM simulations 

List of symbols

\( A_{5} \)


\( d \)

Diameter of the circle inscribed in the contour of the cross section of the tool deforming portion

\( d_{0} \)

Diameter of the hole after reaming

\( D \)

Diameter of the circle circumscribed over the tool deforming portion

\( E \)

Young’s modulus

\( f \)

Feed rate

\( h \)

Height of workpiece

\( i \)

Interference fit (tightness)

\( n \)

Strain hardening coefficient

\( N \)

Number of cycles to failure

\( P \)

Tensile load

\( r \)

Radius of curvature

\( R \)

Load ratio

\( R_{a} \)

Surface roughness

\( R_{z} \)

Height of the initial roughness

\( v \)

Burnishing velocity

\( x_{i} \)

Governing factors

\( Y \)

Objective function

\( z \)

Number of the tool walls

\( \varepsilon_{ \log } \)

Logarithmic strain

\( \varepsilon_{\text{nom}} \)

Nominal strain

\( \nu \)

Poisson’s ratio

\( \sigma \)

Remote stress

\( \sigma_{\text{nom}} \)

Nominal stress

\( \sigma_{t} \)

Hoop stress

\( \sigma_{\text{true}} \)

True stress

\( \sigma_{u} \)

Ultimate stress

\( \sigma_{y} \)

Yield limit



Computer numerical control


Finite element method


Friction stir hole expansion


Hole cold expansion


Microstructure modification


Slide burnishing


Surface plastic deformation



This work was supported by the Bulgarian Ministry of Education and Science and the Technical University of Gabrovo under Contract No. 1801M. The authors extend their special acknowledgements to Dr Yosiph Mitev and Dr Dobri Petkov for his collaboration with the experiments.


  1. 1.
    Champoux LA (1971) Coldworking method and apparatus. USA Patent 3566662, 2 Mar 1971Google Scholar
  2. 2.
    Duncheva GV, Maximov JT, Ganev N (2017) A new conception for enhancement of fatigue life of large number of fastener holes in aircraft structures. Fatigue Fract Eng Mater Struct 40(2):176–189CrossRefGoogle Scholar
  3. 3.
    Mishra RS, Mahoney MW, McFadden SX, Mara NA, Mukherjee AK (2000) High strain rate superplasticity in a friction stir processed 7075 Al alloy. Scripta Mater 42:163–168CrossRefGoogle Scholar
  4. 4.
    Mishra RS, Ma ZY, Charit I (2003) Friction stir processing: a novel technique for fabrication of surface composite. Mater Sci Eng A 341:307–310CrossRefGoogle Scholar
  5. 5.
    Hogenhout F (1987) Method and apparatus for hole coldworking. USA Patent 4665732, 19 May 1987Google Scholar
  6. 6.
    Maksimov YT, Duncheva GV (2014) Device and tool for cold expansion of fastener holes. USA Patent 8915114, 23 December 2014Google Scholar
  7. 7.
    Maximov JT, Duncheva GV, Amudjev IM (2013) A novel method and tool which enhance the fatigue life of structural components with fastener holes. Eng Fail Anal 31:132–143CrossRefGoogle Scholar
  8. 8.
    Easterbrook ET (2001) Method and apparatus for producing beneficial stresses around apertures by use of focused stress waves, and improved fatigue life products made by the method. USA Patent 6230537, 15 May 2001Google Scholar
  9. 9.
    Easterbrook ET, Flinn BD, Meyer CA, Juhlin N (2001) The StressWave™ Fatigue Life Enhancement Process. In: Proceedings of the 2001 aerospace congress, Seattle, Washington, 10–14 Sept 2001Google Scholar
  10. 10.
    Korzynski M (2013) Slide diamond burnishing. In: Korzynski M (ed) Nonconventional finishing technologies. Polish Scientific Publishers PWN, Warsaw, pp 9–33Google Scholar
  11. 11.
    Nee AYC, Venkatesh VC (1982) Bore finishing—the ballizing process. J Mech Work Technol 6(2–3):215–226CrossRefGoogle Scholar
  12. 12.
    Maximov JT (2002) Spherical mandrelling Method implementation on conventional machine tools. Int J Mach Tools Manuf 42(12):1315–1325CrossRefGoogle Scholar
  13. 13.
    Catalogue Ecoroll (2006) Tools and solutions for metal surface improvement. Ecoroll Corporation Tool Technology, MilfordGoogle Scholar
  14. 14.
    Christ RJ, Nardiello JA, Papazian JM, Madsen JS (2010) Device and method for sequentially cold working and reaming a hole. USA Patent 7770276, 10 Aug. 2010Google Scholar
  15. 15.
    Korzynski M (2009) A model of smoothing slide ball-burnishing and an analysis of the parameter interaction. J Mater Process Technol 209(1):625–633CrossRefGoogle Scholar
  16. 16.
    Korzynski M (2007) Modeling and experimental validation of the force-surface roughness relation for smoothing burnishing with a spherical tool. Int J Mach Tools Manuf 47(12):1956–1964CrossRefGoogle Scholar
  17. 17.
    Maximov JT, Duncheva GV, Anchev AP, Ganev N, Amudjev IM, Dunchev VP (2018) Effect of slide burnishing method on the surface integrity of AISI 316Ti chromium–nickel steel. J Braz Soc Mech Sci Eng 40:194. CrossRefGoogle Scholar
  18. 18.
    Maximov JT, Anchev AP, Duncheva GV, Ganev N, Selimov KF (2017) Influence of the process parameters on the surface roughness, micro-hardness, and residual stresses in slide burnishing of high-strength aluminum alloys. J Braz Soc Mech Sci Eng 39(8):3067–3078CrossRefGoogle Scholar
  19. 19.
    Shamdani AH, Khoddam S (2012) A comparative numerical analysis of combined cold expansion and local torsion on fastener holes. Fatigue Fract Eng Mater Struct 35(10):918–928CrossRefGoogle Scholar

Copyright information

© The Brazilian Society of Mechanical Sciences and Engineering 2019

Authors and Affiliations

  • J. T. Maximov
    • 1
    Email author
  • G. V. Duncheva
    • 1
  • A. P. Anchev
    • 1
  • I. M. Amudjev
    • 2
  1. 1.Department of Applied MechanicsTechnical University of GabrovoGabrovoBulgaria
  2. 2.Department of Mechanical EngineeringTechnical University of GabrovoGabrovoBulgaria

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