8/6/2019 Fred Afagh

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Fred Afagh, Carleton University professor of Mechanical and Aerospace Engineering, is trying to develop better

helicopter rotor blades. More specifically, he is dealing with problems associated with using new composite materials

for designing advanced and smart helicopter rotor blades.

It is envisaged that by using Micro Fibre Composites (MFC) one can develop sophisticated smart helicopter rotor

blades in which the active fibres that are integrated into the structure of the blade can be used as actuators to control

the undesirable behaviour of these rotor blades. These are essentially lightweight structures, in this case lightweight

rotating beams.

In order to understand and to be able to predict the behaviour of these rotor blades by using accurate mathematical

models, one needs to develop and use a nonlinear composite beam theory. The development of an accurate dynamic

model for these rotor blades is also essential and will provide the researchers with a powerful tool to investigate and

control behaviour of rotor blades. In developing these models, professor Afagh, along with colleague Robert Langlois

of the Applied Dynamics Laboratory, collaborate together with their graduate students.

For example, a major concern with the operation of shipboard helicopters is a phenomenon that is referred to as

blade sailing which can happen when a helicopter lands on a ship in rough sea conditions. In such cases, during the

engage and disengage phases of rotor operation, while the rotors are turning at lower speeds, they can also be

subjected to high wind-induced aerodynamic forces. Under these circumstances, and without the benefit of the usual

centrifugal stiffening at normal operating speeds, the blade deflections can be problematic.

This excitation, combined with ship deck motion during all but the most benign sea and wind conditions, can cause

excessive deflection of rotor blades, and as a result, the blade can come into contact with the fuselage or tailboom of

the helicopter. This can compromise the safety of the aircraft, resulting in airframe damage, and may bring the

airworthiness of the helicopter into question.

Afagh, Langlois and their graduate students are experimenting with using smart blades to control this phenomenon.

The groups work involves a great deal of development, mathematical modelling and simulation.

The Applied Dynamics lab combines a focus on mathematical modelling and simulation with core

strengths in the areas of multibody dynamics, vehicle dynamics, and shipboard helicopter operation to

perform leading-edge theoretical and applied research in these areas. Unique laboratory facilities and

close interaction with industry, government, and other research organizations support strong emphasis on

comprehensive validation of computational models as well as developing computation tools that meet the

design objectives of end-users.