Fatigue test method and fatigue test equipment

摘要

PROBLEM TO BE SOLVED: To correctly evaluate the fatigue strength of a test-piece having a relatively small diameter.SOLUTION: A fatigue testing method allows an ultrasonic vibrator to oscillate vertical vibrations by an electric power outputted from an oscillator and amplifies the vibrations by a columnar horn which becomes smaller as moving toward a low end side so as to be given to a columnar testing piece, and thus evaluates the fatigue strength. The horn low end part is mounted with an auxiliary horn formed in a columnar shape equal to or less than the outer diameter of the horn low end part and the diameter in the low end part is smaller in diameter than the upper end part and resonating with the vibrations of the horn. The vibrations amplified by the horn is amplified more than the vibrations which generate the stress necessary for the fatigue-test by the auxiliary horn, and a male screw for the test-piece attachment erected on the test-piece upper end part is screwed into a female screw hole for the test-piece attachment fitted to the male screw, and the test-piece is fitted to the auxiliary horn. Then, the test piece is made resonated with the vibrations of the auxiliary horn to generate the maximum stress to the evaluation object region and also to generate the stress necessary for the entire length of the evaluation object region.SELECTED DRAWING: Figure 1