Alenia Shm Fiber Optic Bragg Grating (Fobg) Strain Sensors Technology: Applications And Requirements

Abstract : In this paper, the description of Alenia SHM technology by means Fibre Optic Bragg Grating (FOBG) for aeronautic field application is reported; CNR IMM and MARS are the Italian partners have worked together with Alenia to the technology development in the last years. In comparison with the conventional and already tested sensors and methods, the sensors in optic fibres show several advantages in terms of weight and size reduction, no EMI, measure long duration stability. Between these, the sensors with Bragg grating represent a valid solution, being moreover available in commerce with efficient and a repetitive characteristics. With these sensors, bonding techniques on metallic and composite parts surface are already tested together with FOBG embedding procedure in carbon resin component (Alenia patent). The instrumentation to analyse FOBG signals, are going to be available on commerce in typical configuration for laboratory applications, but are not again suitable for flight application. So, there is the exigency to define and accomplish, starting by off the shelf components and if necessary by custom components developing, a reliable FOBG instrumentation that satisfy airworthiness requirements necessary to an aeronautic application. This instrumentation is defined from the indivisible connection between a dedicated optoelectronic HW configuration and a suitable SW oriented to typical aeronautic exigencies and to data management objectives. In this article the application of sensors on different type of structures, the adopted devices and the future activities for flight tests are described.