Fatigue testing at ultrasonic frequencies makes it possible to investigate the fatigue properties of materials in an effective and time saving manner. The mechanical and electrical components of ultrasound equipment are described in detail. Different testing and evaluation procedures are reviewed. Recommendations on how to perform high frequency fracture mechanics studies and to evaluate experimental results are described. Recent developments for multiaxial loading, for performing in-service loading fatigue experiments, and for realising high frequency torsional vibrations are described. A survey of fatigue investigations of metallic materials, composites, metallic glass, and ceramics, determined with the ultrasound method, is presented. Intrinsic frequency effects are reviewed, emphasising the influences on dislocation structures, crack initiation, and fatigue crack growth for pure metals and for technical materials. The advantages and disadvantages of the ultrasound method are compared with thos...

Fatigue crack growth and threshold measurements at very high frequencies

Fatigue and fatigue crack growth of aluminium alloys at very high numbers of cycles

Fatigue crack initiation and growth on a steel in the very high cycle regime with sea water corrosion

Very high cycle fatigue of a high strength steel under sea water corrosion: A strong corrosion and mechanical damage coupling

Performing fatigue tests at ultrasonic frequencies, e.g. 20 000 Hz, allows one to perform experiments beyond 10 9 and 10 10 cycles within half a day or a week, respectively. The testing technique has led to the construction of fatigue machines of high technical standard. Use of the ultrasound technique to study the mechanisms of crack initiation in pure metal single crystals, in cast alloys with voids being crack initiation sites, and in complicated fibre-reinforced laminates is reported. Likewise, use of ultrasonic loading to study the mechanisms of crack propagation is discussed, as well as LEFM principles; especially when these principles cannot be applied. It is shown how crack growth retardation with increasing crack length is attained in fibre-reinforced laminates by the effect of fibre bridging. Additional experimental possibilities, e.g. random loading, variation of mean load, superposition of shear loads, variation of temperature and environment, and not only axial but also torsional loading at ultrasonic frequency, and recent research results are discussed.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1460-2695.1999.00180.x

Wu Tieying

Papers

Application of fracture mechanics concepts in ultrasonic fatigue