SHM System for Small Aircrafts and Composite Repairs of Aircraft Structures

The paper provides information about real time experimental loading, strains monitoring and evaluation of the fatigue damage in critical parts of the small sport aircraft during their service life. Developed Structure Residual Life Monitoring System provides direct evaluation of the residual life after each landing, Such direct fatigue evaluation is unique in the ultra light or sport aircraft category and it can significantly increase operational safety of this aircraft category. The whole calculation process is based on measured 'g' spectrum, correlation formulae 'g' vs. stress and on fatigue properties of the structure critical places. In the second part, the possibilities of utilization of fatigue crack repairs in selected critical places and their structural health monitoring are described. Capability of acoustic emission method in course of health monitoring of composite repair of cracked aluminium alloy plates as well as fibre optic sensors with a Bragg's gratings or strain gauges were tested. These methods can indicate further crack growth under repair as well as the debonding of composite patches.