The investigation of highcycle loading from the ...（调查的highcycle加载u2026）.pdf

The investigation of high-cycle loading from the perspective of seismology R. Kliukas, M.K. Leonavičius, G. Petraitis R. Stonkus Vilnius Gediminas Technical University, Lithuania SUMMARY: High-cycle loading, making a part of a broad spectrum of vibrations and seismic loads, may be considered 9 separately, when the number of cycles reaches 10 . The stresses developed under such loading are below the ultimate strength. In designing various building constructions, as well as mining equipment, and planning their long service life, pulsating loads should be evaluated in addition to commonly applied loads. Long-term effect of these loads on the particular elements of metal structures is similar to the phenomenon of metal fatigue, developing due to variable loading. The paper presents the results obtained in the experimental analytical research, aimed at evaluating strength of materials under high-cycle loading. Specimens’ resistance to crack propagation was tested, based on the specified and extended methods. The limit stress intensity factors and the relationships between the crack growth rate and stress intensity factor are determined. The analysis of crack formation and propagation in the flaw area based on the use of the scanning electron microscope (SEM) is performed. The effect of non-uniform zones on crack development is also determined. The results obtained may be used for calculating strength and durability of structures subjected to high-cycle loading as well as for determining their safety factors. Keywords: crack, high-cycle fatigue, str