Helicopter fuselage crack monitoring and prognosis through on-board sensor network

An advanced method for maintenance cost reduction and structural safety improvement of helicopters frame is presented. In this approach, residual life evaluation is based on the real time acquisition of the crack damage, by means of dedicated sensor network, and a focused FE model of the fuselage. Recently, the European Defence Agency has proposed a Joint Investment Programme on Innovative Concepts and Emerging Technologies (JIP-ICET). Following this call, the HECTOR proposal was submitted for evaluation; the purpose of this proposal concerns the application of methods for identification, monitoring and prognosis of potential damages (like cracks) in the fuselage of a helicopter. The key issues of this activity will be related with structural assessment, real time acquisition and advanced data fusion process. In particular advanced models for the stress assessment, will be used for the identification of the most critical area for crack nucleation and growth; these area will be monitored with a on board network of last generation sensors (Comparative Vacuum Monitoring, Optical Fibre Sensors, Crack Propagation Gauges, etc). Moreover the final research aim is to obtain a reliable method to assess the damage accumulated in the fuselage by means of on-line advanced prognostic models that allow the real time definition of schedule for periodic and special inspections. In this paper, a review of the state-of-the-art concerning the Structural Health Monitoring applied on helicopter fuselages is described. Moreover an example of application of a numerical FE models of cracked structures and on residual life evaluation is presented.