科研之友
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摘要
Metals used in industry for structures and aero-engine components are sometimes subjected to very high cycle fatigue (VHCF) damage during their working service. In this paper, a novel method is presented to determine the size and location of a circular crack located within a metal specimen under 20 kHz VHCF loading conditions. The method is based on an analysis of the temperature rise on the surface of the specimen and correlation of this temperature rise to the energy dissipation in the plastic zone of the crack. The approach taken is to first determine the heat source location and strength using an inverse heat transfer calculation based on the surface temperature measurements. Next, the relationship between the heat and the material hysteresis loop in the plastic zone, which is a function of stress intensity factor and vibration amplitude cyclic loading of the specimen, is found. The calculation of the stress intensity factor under vibrational loading is often an obstacle in VHCF research because there is currently no standard or existing formula. In this paper a general polynomial formula for the stress intensity factory under 20 kHz loading conditions is obtained using a finite element modeling approach as a function of the specimen's material properties and position and size of the internal crack.
- 出版日期2016-12
- 单位南京航空航天大学
