Temperature-frequency evolution during 20 kHz cyclic loading of Dual- Phase 780 steel

Abstract

Ultrasonic machine, which operates at around 20 kHz, is used to quickly get the fatigue behavior in the very high cycle fatigue domain. Cyclic loading at such high frequencies is accompanied by selfheating of the test specimen [1]–[3]. The self-heating magnitude depends on the material and cooling system. It is also accompanied by changes in loading frequency of testing. In contrast to thetemperature evolution and to our knowledge, the frequency evolution during an ultrasonic fatigue test has been very little studied. In this paper, the changes in both specimen temperature and loading frequency during ultrasonic cycling for the Dual-Phase 780 steel are investigated.