Development of a miniaturized hour-glass shaped fatigue specimen

Diametral strain-controlled push-pull fatigue tests with zero mean strain w ere carried out with miniaturized hourglass shaped specimens of an austenit ic stainless steel in solution annealed condition at room temperature. The specimens had a diameter of 1.25 mm at the minimum cross section and a tota l length of 25.4 mm. The number of cycles to failure (N-f) was equal to or slightly greater than that obtained with standard size specimens. N-f was a lso revealed to be rather insensitive to the specimen load axis offset, ind icating that the requirement of the specimen alignment to the load axis was not very severe for the miniaturized specimen. (C) 1998 Published by Elsev ier Science B.V. All rights reserved.