Experimental and Theoretical Investigation on Notched Specimens Life Under Bending Loading

Authors: Nasim Daemi, Gholam Hossein Majzoobi

Abstract:

In this work, bending fatigue life of notched specimens with various notch geometries and dimensions is investigated by experiment and Manson-Caffin theoretical method. In this theoretical method, fatigue life of notched specimens is calculated using the fatigue life obtained from the experiments for plain specimens (without notch). Three notch geometries including ∪-shape, ∨-shape and C -shape notches are considered in this investigation. The experiments are conducted on a rotary bending Moore machine. The specimens are made of a low carbon steel alloy, which has wide application in industry. The stress- life curves are captured for all notched specimen by experiment. The results indicate that Manson-Caffin analytical method cannot adequately predict the fatigue life of notched specimen. However, it seems that the difference between the experiments and Manson-Caffin predictions can be compensated by a proportional factor.

Keywords: fatigue life, Mason-Caffin method, notchedspecimen, stress-life curve.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1334167

References:

[1] G. Stalk, "A study of fatigue notch sensitivity of 2014-T and 7075-T at elevated temperatures", 1955, PhD Thesis, California, Institute of Technology, Pasadena, California, page 45-63.
[2] P. Luk'aˇs, L. Kunz, M. Svoboda, "Fatigue notch sensitivity of ultrafine-grained copper", Materials Science and Engineering A, 2005, Vol. 391, pp. 337-341.
[3] Zheng X.L., Wang H., Yan J.H. "Notch strength and notch sensitivity of polymethyl methacrylate glasses", Materials Science and Engineering A, 2003,Vol. 349, pp. 80-88.
[4] A. Masayuki, T. Keiro, , "Effect of carburizing on notch fatigue behavior in AISI 316 austenitic stainless steel", Surface & Coatings Technology, 2006,Vol. 200, ,pp. 6073-6078.
[5] G.H. Majzoobi, N. Daemi, "The study of notch geometry on fatigue life using notch sensitivity factor", Transaction of the Indian Institute of Metals Journal. Vol. 63, 2010, pp.547-55.
[6] MM. Megahed, AM. Eleiche, NM. Abd-Allah. "Low-cycle fatigue in rotating cantilever under bending I: theatrical analysis", Int. J. Fatigue, 1996, Vol. 18(6), pp. 401-12.
[7] M. M. Megahed, A. M. Eleiche, N. M. Abd-Allah. "Low-cycle fatigue in rotating cantilever under bending II: Experimental investigation on smooth specimens", Int. J. Fatigue, 1996,Vol. 18(8), pp. 577-92.
[8] M. M. Megahed, A. M. Eleiche, N. M. Abd-Allah, "Low-cycle fatigue in rotating cantilever under bending III: Experimental investigation on notched specimens", Int. J. Fatigue, 2005, pp. 271-280.
[9] R.W. Hertzberg, "Deformation and fracture mechanics of engineering materials", 1996, 4th ed. J. Wiley & Sons: New York 1996, page 230 (Farsi text).