Material Selection Using Hybrid Grey Relation Analysis Approach Based on Weighted Entropy for Ranking: The Case of Helicopter Rotor Blade

Abstract

Engineering design relies highly on the selection of suitable materials. Because there are many engineering materials, selecting a suitable material for a product requires a systematic selection approach. This paper provides a hybrid strategy for choosing the best material for an engineering design to give the best performance at the lowest cost based on Ashby's performance indices. Then, it ranks the result by the grey relational approach integrated with the Weighted Entropy Method to choose the optimum material for the main rotor blade of a helicopter. Different materials used for manufacturing rotor blades, such as Aluminium alloys, titanium alloys, steel, composites, and wood, have been discussed. The performance indices chosen are stiffness, strength, and fracture toughness. The performance indices proved that the composite material has excellent structural strength, stiffness, and toughness. The result shows that CFRP is the best material for manufacturing helicopter rotors, while wood and steel were the best and cheapest when the design had to be economical.