Optimization Methods for the Weight of Agusta Helicopter Main Gearbox

Nowadays, one of the most important challenges in engineering sciences is optimization of the existing designs due to the competitive industrial market. In aviation industry, weight and life of components are important criterions in their design. As an example, optimizaing the weight of main gearbox of helicopters with acceptable performance and fatigue life are major concerns. In this paper, design parameters of Agusta helicopter main gearbox has been determined by three different optimization methods Genetic Algorithm (GA), Particle Swarm Algorithm (PSO) and the Gravitational Search Algorithm (GSA). The objective function is the weight of the gears with appropraiate constrains which are based on geometrical limitations. Alsosafety factors according to the AGMA standards are considered. The design parameters are gear width as a continuous variable and normal module as a discrete parameter. Comparison of the results show that all three optimization methods are able to minimize the weight of the gearbox in the range of 23 to 27% comparing with the existing one; but, GSA not only gives the best optimized solution it also has the highest convergence rate.