Evaluation of Fatigue Life Reduction Factors at Bolt Hole in Double Lap Bolted Joints Using Volumetric Method

Document Type: Research Paper

Authors

1 Department of Mechanical Engineering, University College of Nabi Akram (UCNA),Tabriz, Iran

2 Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran

3 Department of Mechanical Engineering, Tabriz Branch, Islamic Azad University ,Tabriz, Iran

Abstract

In this research, the influence of bolt preload on the fatigue strength of 2024-T3 aluminium alloy double lap bolted joints has been studied experimentally and numerically. To do so, three sets of the specimens were prepared and each of them subjected to tightening torque of 1,2.5 and 5 N-m and then fatigue tests were conducted under various cyclic axial load levels. In the numerical method, the influence of bolt preload on the fatigue life of double lap bolted joints were studied using the values of fatigue notch factor obtained by volumetric approach. In order to obtain stress distribution around the notch (hole) which is required for volumetric approach, nonlinear finite element simulations were carried out. To estimate the fatigue life, the S-N curve of plain (un-notched) specimen and the fatigue notch factors obtained from volumetric method were used. The estimated fatigue life was compared with those obtained from the experiments. The investigation reveals that there is a good agreement between the life predicted by the volumetric approach and the experimental results for various specimens with different amounts of bolt preload. The volumetric approach and experimental results showed that the fatigue strength of specimens were improved by increasing the bolt preload as the result of compressive stresses which appeared around the bolt hole.

Keywords

[1] Huda Z., Zaharinie T., Min G., 2010, Temperature effects on material behavior of aerospace aluminum alloys for subsonic and supersonic aircraft, Journal of Aerospace Engineering 23(2): 124-128.
[2] Mahadevan S., Shi P., 2001, Corrosion fatigue reliability of aging aircraft structures, Progress in Structural Engineering and Materials 3(2): 188-197.
[3] Buyuk M., Kan S., Loikkanen M., 2009, Explicit finite-element analysis of 2024-t3/t351 aluminum material under impact loading for airplane engine containment and fragment shielding, Journal of Aerospace Engineering 22(3): 287-295.
[4] Mao J., Kang S.B., Park J.O., 2005, Grain refinement, thermal stability and tensile properties of 2024 aluminum alloy after equal-channel angular pressing, Journal of Materials Processing Technology 159(3): 314-320.
[5] Pratt J., Pardoen G., 2002, Numerical modeling of bolted lap joint behavior, Journal of Aerospace Engineering 15(1): 20-31.
[6] Ireman T., 1998, Three-dimensional stress analysis of bolted single-lap composite joints, Composite Structures 43(3): 195-216.
[7] Pratt J., Pardoen G., 2002, Comparative behavior of single-bolted and dual-bolted lap joints, Journal of Aerospace Engineering 15(2): 55-63.
[8] Esmaeili F., Chakherlou T.N., Zehsaz M., Hasanifard S., 2013, Investigating the effect of clamping force on the fatigue life of bolted plates using volumetric approach, Journal of Mechanical Science and Technology 27(12): 3657-3664.
[9] Valtinat G., Hadrych I., Huhn H., 2000, Strengthening of riveted and bolted steel constructions under fatigue loading by preloaded fasteners experimental and theoretical investigations, Connections in Steel Structures IV.
[10] Chakherlou T.N., Abazadeh B., Vogwell J., 2009, The effect of bolt clamping force on the fracture strength and the stress intensity factor of a plate containing a fastener hole with edge cracks, Engineering Failure Analysis 16(1): 242-253.
[11] Chakherlou T.N., Alvandi-Tabrizi Y., Kiani A., 2011, On the fatigue behavior of cold expanded fastener holes subjected to bolt tightening, International Journal of Fatigue 33(6): 800-810.
[12] Budynas R.G., Nisbett J.K., 2011, Shigley’s Mechanical Engineering Design, 9rd ed, McGraw-Hill.
[13] Dowling N., 2012, Mechanical Behavior of Materials: Engineering Methods for Deformation, Fracture and Fatigue, Prentice Hall Inc, New Jersey.
[14] Esmaeili F., Hassanifard S., Zehsaz M., 2011, Fatigue life prediction of notched specimens using the volumetric approach, Journal of Solid Mechanics and Materials Engineering 5(9): 508-518.
[15] Hassanifard S., Zehsaz M., Esmaeili F., 2011, Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints, Journal of Mechanical Science and Technology 25(3): 647-653.
[16] Adib H., Pluvinage G., 2003, Theoretical and numerical aspects of the volumetric approach for fatigue life prediction in notched components, International Journal of Fatigue 25(1): 67-76.
[17] Tryon R. G., Dey A., 2003, Reliability-based model for fatigue notch effect, SAE International 1: 01-0462.
[18] Pluvinage G., 2004, Fracture and Fatigue Emanating From Stress Concentrators, Kluwer Academic Publishers, Dordrecht.
[19] Peterson R. E., 1974, Stress Concentration Factors, John Wiley & Sons, New York.
[20] Neuber H., 1961, Theory of Notch Stresses: Principles for Exact Calculation of Strength with Reference to Structural Form and Material, USAEC Office of Technical Information, Oak Ridge, Tenn.
[21] Heywood R.B., 1962, Design Against Fatigue, London, Chapman and Hall.
[22] Pluvinage G., 1997, Application of notch fracture mechanics to fracture emanating from stress concentrators. Advances in Computational Engineering Congress of Computational Engineering Sciences 97: 213-218.
[23] Swanson Analysis Systems Inc, 2004, ANSYS, Release 9.