A feasibility study on the behaviour of a helicopter smart blade aimed at blade tip morphing

In this paper, the behaviour of a hingeless helicopter blade with a novel integrated smart morphing actuator is studied. The proposed smart device is aimed at the reduction of BVI noise through transformation of the blade tip shape into an anhedral tip type and is based on the concept of a variable-stiffness blade. In detail, the blade morphing is obtained through joint action of a magneto-rheological-fluid (MRF) device, shape-memory alloy (SMA) tie-rods and a set of concentrated masses properly distributed spanwise. In this architecture, the MRF system has to provide local bending-stiffness reduction and concentrated masses have to provide inertial moments whereas the SMA tie-rods have to mould the blade tip shape. Since the equilibrium configuration of the smart blade deeply depends on the interaction between the aeroelastic response and the actuation loads, in this work a numerical investigation examines potentiality and shortcomings of the proposed integrated smar t system to morph a realistic blade with respect to the baseline configuration.