Fatigue strength of marine shafting¹

Article type: Research Article

Authors: Smedley, G.P. | Batten, B.K.

Note: [1] Paper read before the North East Coast Institution of Engineers and Shipbuilders on 24th February 1961, Newcastle upon Tyne.

Abstract: The results of torsional fatigue tests on forged mild-steel shafts, 3 in. in diameter and having transverse holes of different diameters, are presented and discussed. It is shown that the theoretical stress-concentration factors for shafts having these notches and loaded in torsion, may be considerably in excess of published values. The importance of radiusing the ends of oil holes to obtain improved fatigue strengths is indicated. The influence of repairs by arc welding on the torsional fatigue strength of cast-steel test pieces is considered. The results of tests on test pieces, 3 in. in diameter and prepared by two principal steel foundries are detailed. These show that, provided good practices are employed, the fatigue strength can be at least equal to the value for forged steel shafts of the same tensile strength. Brief reference is made to sea-water corrosion fatigue. This is considered to be responsible for many service failures of marine machinery. Data mainly relate to the influence of frequency of loading on the numbers of cycles and times to failure at particular levels of stress.

DOI: 10.3233/ISP-1961-87901

Journal: International Shipbuilding Progress, vol. 8, no. 79, pp. 105-118, 1961