MULTI-DAMAGES MONITORINGIN CFRP LAMINATED COMPOSITES

摘要

Metallic structure monitoring has proved able to reduce both the risks of accident and maintenancecosts. Today monitoring systems designed for composite structures are limited to some kind ofdegradation like ones created by impacts. However, damage mechanisms in composite structures aremultiple and complex, they don’t only come from exceptional loading like impacts; a compositestructure is gradually damaged under a static or a fatigue loading.However we have to control and supervise those damage mechanisms to ensure the safety and themaintenance of systems. Today models able to predict the evolution of damages exist but theirprecision is limited because of the uncertainties linked to loading, initial material state andcharacteristics of the material. To remedy this problem we work on a monitoring system associatingpredictive models with periodic or continuous measurements. The measured variables could be astrain, a level of diffuse damage or characteristics of a delamination or a crack (position, size).In this paper, after the description of an application: a helicopter blade, we present a method based onthe electrical impedance measurement to monitor a delamination zone and the use of the Lamb wavespropagation to detect a crack along a structure edge. To finish we talk about the ways considered tomeasure the level of diffuse damage.