Abstract:

A new method - reverse educing method is put forward in t his paper, which is to estimate the vibration stress of aeroengine blade un der rotating state. Based on the fracture mechanics theory, the vibration stress intensity factor K v of the blade can be worked out by t he value of crack's growth ratio da/dN, which is gotten from the actual fracture section, and the relationship between da/dN and the stress intensity factor amplitude ΔK. Through static, modal and crack stress intensity factor analysis, the vibration stress of blade under rotating state before fracture can b e calculated out finally. The results will be very significant for trouble diagnosing and shooting of aeroengine blades.

Key words: blade, vibrat ion stress, stress intensity factor, finite element analysis method