航空工业中的微动损伤及研究概况

本文介绍飞机及发动机中出现的微动损伤概况。飞机构件实验室实验中约有90％的破坏均发生在有微动环境处,微动作用使材料的疲劳强度降低了30～80％。本文还介绍了微动损伤的典型特征。

FRETTING DAMAGE IN AIRCRAFT INDUSTRY AND THE GENERAL SITUATION OF RESEARCH

Fretting damage occurs on contact surfaces of components which are clamped together and are subjected to tangential oscillating movement with small amplitude. Usually, the normal force is larger and the cyclic relative sliding motion is smaller, so that the flow of debris away from its place or origin in the contact interface is restricted. The formation of debris in a fretting contact surface is a sign that fretting damage has occurred.Fretting damage is often used to denote fretting corrosion, fretting wear, fretting fatigue.Fretting can not only cause a deterioration of surface quality, but also initiate fatigue cracks which may drastically lower the fatigue strength of some materials. Experimental results have shown in this paper; the fretting fatigue limits for 0.45C steel and high strength aluminium alloy specimens were reduced by approximately 30~55%, compared to non-fretted specimens at 107 cycles. In the most severe case, the fatigue strength was reduced by 80% or so.Fretting damage arises in any engineering device, as long as a source of vibration is present. In laboratory tests on aircraft components, it was found that about 90% of all failures occured at points where fretting existed. In aircrafts and gas turbine engines, fretting fatigue is increasingly being recognized as a major source of failure.This paper describes the general situation of fretting damage in aircraft industry and illustrates the typical characteristics of fretting damage. In other countries, there are many universities and scientific research groups who are undertaking this research work. We are continuously engaged in this research work, it will bring significant influences on aircraft reliability design.