22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-P3.2

A STUDY OF OPTION OF MATERIAL FATIGUE PROPERTY DESCRIPTION FOR FATIGUE LIFE PREDICTION

B. Wang (1, 2), Q. Yang (2)
(1) Xi’an Aircraft Design & Research Institute, Xi’an, PRC (2) Northwestern Polytechnical University, Xi’an, PRC

Keywords: fatigue life, material properties, cyclic hardening

This paper investigates some new characteristics of cyclic hardening/softening behavior of airframe materials. A new method is presented, which is applied to describe the cyclic stress~strain behavior at any strain ratio, strain range and number of cycles. The comparison is made among different options of fatigue property descriptions. The conclusions are drawn as following: (1)There is no real ‘stable’ hysteresis curves in transient cyclic stress~strain behavior. (2)It is not acceptable to adopt Manson-Coffin formula to predict the fatigue life for asymmetric cyclic strain. (3)Applying local stress-strain method to predict the fatigue life, the option of transient stress~strain curve combined with equivalent strain~life curve is more reasonable at present.

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