Abstract To address the demand for long-life durability tests on thin-walled materials like aeroengine blades, this paper proposes an ultrasonic accelerated fatigue testing method suitable for biaxial bending fatigue experiments. Starting from the principle of simple harmonic vibration, a TC4 cross biaxial ultrasonic fatigue specimen with a natural frequency of 20 kHz, designed for both fourth and third-order bending vertical superposition, was developed. The vibration frequency and modes of this method were determined using strain gauges, and the stresses in ultrasonic bending fatigue were calibrated using a laser sensor. The study conducted experimental validations of very-high-cycle fatigue performance under biaxial bending loading. By analyzing the S-N curves, crack propagation paths, and fracture morphologies under different loading conditions, the characteristics of biaxial bending very-high-cycle fatigue failure behaviors were revealed.
2024, Vol. 45 
