The preliminary design of the SHARCS rotor blade

Abstract

R e p r o d u c e d with p e r m issio n o f th e co p y r ig h t o w n e r . F u rth er rep ro d u ctio n p roh ib ited w ith o u t p e r m issio n .

Strain measurement of composite materials using fibre optic sensors

“…One step in the development of SHARCS is experimental wind tunnel testing of its sub-systems using a one meter long fibre reinforced composite Mach scaled rotor blade, the preliminary design o f which was carried out by Mikjaniec (2006); it is hereby referred to as the SHARCS rotor blade. The performance of SHARCS can be evaluated by dynamically monitoring the structural deformation and vibration behaviour of the rotor blade during wind tunnel testing.…”

“…Based on the preliminary SHARCS rotor design presented by Mikjaniec (2006), system operating parameters such as measurement range, speed and resolution will be estimated, followed by a brief look at the system constraints.…”

“…Estimating the largest strains in the structure during these two extreme load cases will establish a target measurement range for the system. The loads and crosssectional properties used in these estimates are those determined by Mikjaniec (2006).…”

“…The axial strain due to extension is related to the centrifugal force by equation 5.2, Mikjaniec (2006), where the subscript k denotes the properties of an individual lamina in the cross-section.…”

“…The sampling rate o f the system will limit its ability to recognize structural vibrations of higher frequencies; the system must therefore operate at a minimum speed relative to the structural dynamics of the SHARCS rotor in order to be effective in monitoring structural vibrations. The key natural elastic frequencies of the structure are calculated by Mikjaniec (2006) as listed below in cycles per revolution (per rev) and also in cycles per second (Hz) at the operating speed of the rotor which is 150 rad / 5. Assuming that a sampling rate of 6 per cycle is the minimum to adequately recognize a sinusoidal form, the system would have to operate at a speed of no less than 834 Hz.…”