Technical review of specimens under ultrasonic fatigue test

An accelerated ultrasonic fatigue test(UFT) has been used for analyzing very high cycle fatigue( VHCF, Nf > 107). This study reviews how the test specimen is to be determined. We focus on UFT using a resonance of 20 kHz. The specimen geometry is determined by selecting test materials by using a dynamic Young's modulus and wavelength of 20 kHz. The dynamic Young's modulus is calculated at the resonant frequency. Through a resonant vibration test at 20 kHz, the length of the specimen is calculated. By determining the shape of the specimen, the stress during the UFT is calculated. The UFT results should be comparable at the test frequency and the specimen geometry obtained by the conventional fatigue tests. �� 2013 The Korean Society of Mechanical Engineers