ABSTRACT

For the ultrasonic fatigue machines to work correctly, stress calibration is necessary. The first objective of the calibration is to make the test system vibrate in resonance at ultrasonic frequency of about 20kHz. Among the important factors of concern is the variation of Young’s modulus of the material due to the high frequency or non-uniform temperatures. Although some measures for calibration have been mentioned in previous sections, it is necessary to present, in this appendix, the detailed calibration procedures for the low temperature test system described earlier. The principles for the calibration of machines operated at room temperature are the same; those procedures will be simpler.