| 摘要 |
PURPOSE:To enable life and time strength to be readily obtained, by making the test piece dipped in a liquid longitudinally oscillate by using an ultrasonic current and detecting the change in the amplitude of the longitudinal oscillation due to the change in the natural frequency of the test piece as a result of the production of corrosion fatigue cracks. CONSTITUTION:A test piece 3 is dipped in the liquid in a corrosion liquid chamber 13 with the corrosion liquid being circulated between the liquid chamber 13 and a storage chamber 11 by a pump 12. The test piece 3 is attached to the end of an amplitude enlarging horn 2 of an ultrasonic vibrator 1 and and continuously made to longitudinally oscillate by the ultrasonic current generated from an ultrasonic oscillator 4 in order to perform a corrosion fatigue test. After a long-time test, when minute cracks are produced in the surface layer of the test piece 3, its nature frequency changes and consequently the amplitude of the longitudinal oscillation also changes. The change in the amplitude is detected by an impedance change sensor 6, the oscillation of the test piece 3 is stopped and the period of time until that time is recorded. |
