Static pre-stretching-ultrasonic bending fatigue test sample and design method

The invention relates to a static pre-stretching-ultrasonic bending fatigue test sample and a design method, and belongs to the field of metal material bending fatigue performance and durability test.The test sample is H-shaped, and four shoulders with thicknesses of m and semi-cylindrical surfaces are arranged at the end part L of the test sample. The design method comprises the following steps: determining material parameters and partial geometric dimensions; calculating the resonance length of the static pre-stretching-ultrasonic bending fatigue test sample based on a resonance length analytical formula of the ultrasonic three-point bending test sample; establishing a three-dimensional model of the static pre-stretching-ultrasonic bending fatigue test sample, calculating the inherent frequency of the static pre-stretching-ultrasonic bending fatigue test sample, and performing continuous correction according to an analysis result, so that the frequency corresponding to the bending mode of the test sample is