OBSERVATIONS ON FATIGUE CRACK GROWTH AND FATIGUE LIFE OF RIVETED LAP JOINTS

Authors

  • Andrzej SKORUPA AGH University of Science and Technology
  • Małgorzata SKORUPA AGH University of Science and Technology
  • Tomasz MACHNIEWICZ AGH University of Science and Technology
  • Andrzej KORBEL AGH University of Science and Technology

DOI:

https://doi.org/10.7494/mech.2012.31.3.108

Keywords:

riveted joints, fatigue life, crack initiation, fatigue crack growth

Abstract

Effects of variables related to design and production of riveted lap joints representative of longitudinal sheet connec­tions for a pressurized transport aircraft fuselage were experimentally investigated. The specimens from an aircraft Al alloy D16 Alclad sheets of three different thicknesses (1.9, 1.2 and 0.8 mm) were assembled under load control using round head rivets and rivets with the compensator from a P24 Al alloy. For the joints from 1.9 mm thick sheets fatigue tests indicated a dependency of the crack initiation site and crack path on the squeeze force level and on the rivet type. At the same time, increasing the squeeze force led to improved fatigue properties of the joints, specimens assembled using the rivets with the compensator showing fatigue lives consistently longer than joints with the round head rivets. All ob­served trends have been explained based on hole expansion and load transfer measurements. For thin sheets connected using the round head rivets, local deformations and indentations under the driven rivet head promoted crack initiation and failure in the adjacent sheet. Fatigue test results indicated that the detrimental effect of this type imperfections could outweigh the benefits associated with a decrease in secondary bending due to thinning the sheets. The rivets with the compensator were observed to cause significant local imperfections beneath the manufactured head, which adversely affected the joint fatigue performance.

Downloads

Download data is not yet available.

References

Müller R.P.G. 1995, An experimental and analytical investigation on the fatigue behaviour of fuselage riveted lap joints. The significance of the rivet squeeze force, and a comparison of 2024-T3 and Glare 3, PhD thesis, Delft University of Technology, Delft.

Schijve J. 1972, Some elementary calculations on secondary bending in simple lap joints, Report NLR TR 72036, National Aerospace Laboratory, Amsterdam.

Schijve J., Skorupa M., Skorupa A., Machniewicz T., Gruszczyński P. 2004, Fatigue crack growth in the aluminium alloy D16 under constant and variable amplitude loading, Int. J. Fatigue, vol. 26, pp. 1-15.

Skorupa A., Skorupa M. 2012, Riveted lap joints in aircraft fuselage. Design, Analysis and properties, Solid Mechanics and Its Applications Bookseries, Springer.

Skorupa M., Skorupa A. 2010, Load transmission and secondary bending in lap joints of aircraft fuselage, Fatigue of Aircraft Structures Monographic Series, A. Niepokólczycki (Ed.), Institute of Aviation Scientific Publications, Warsaw.

Skorupa M., Skorupa A., Machniewicz T., Korbel A. 2010, Effect of production variables on the fatigue behaviour of riveted lap joints, Int. J. Fatigue, vol. 32, pp. 996-1003.

Downloads

Issue

Section

Articles