Deformation failure mode of aviation bearing seat

The deformation failure of the bearing seat can be divided into two types: elastic deformation failure and plastic deformation failure. The former refers to the excessive elastic deformation that occurs during operation due to insufficient stiffness of the bearing seat, which affects the support and positioning functions of the bearing seat and causes abnormal operation of the engine rotor system; The latter refers to the failure of the bearing seat caused by excessive plastic deformation. According to the causes of plastic deformation of the bearing seat, there are two types of failure situations. One is due to insufficient strength of the bearing seat, which leads to stress levels in the working state exceeding the yield strength of the bearing seat material; Another reason is that the dimensional stability of the bearing seat is insufficient, causing small irreversible changes in size or shape of the parts in constant or non constant environments.

The dimensional stability of a component is directly related to the microplastic deformation of the material, and is the main characteristic of the material properties of precision mechanical components. It represents the ability of the component to resist permanent deformation under working environmental conditions without external forces or under stress below the elastic limit after heat treatment and processing. It is generally believed that the insufficient dimensional stability of parts is caused by two factors: the instability of the phase and microstructure of the material, and the excessive residual internal stress during the heat treatment and mechanical processing of the blank

If the component has a stable phase composition, the change in its size is mainly related to the relaxation of internal stress; And for parts with metastable structures, the change in size is the result of the combined action of the two. At this time, the transition from phase to structure sharply strengthens the relaxation process of residual internal stress