Structural shape sensing for variable camber wing using FBG sensors

Abstract

In this paper, a variable camber wing, which comprises a flexible skin, a metal sheet, and a honeycomb structure, is presented. Shape memory polymer (SMP) is selected for the use of flexible skins. Embedded heating wire springs act as the activation system for the SMP. Experimental result shows that the inherent separation does not occur between the heating elements and SMP upon elongation because of elasticity of wire springs. The deformation of SMP skins at different temperature conditions is analyzed in order to establish the relationship between the deformation of the skin and pre-strain applied in the SMP skin. Fibre Bragg Grating (FBG) sensors, with flexibility and small size, are bonded on the surface of the metal sheet to measure the deflection on the some certain points. The relation of the strain on the upper surface of metal sheet and the deflection of the trailing-edge is established to ensure the position of the bonded FBG sensors. The curve shape of the bending metal sheet can be reconstructed using the calibration information.