MULTIOBJECTIVE OPTIMUM DESIGN OF GEAR BOX-ISSUES AND CHALLENGES

摘要

Gear box is the most commonly used mechanical element in various kinds of machines which should be strong enough to withstand the sudden variations in load. Hence there is a need for designing an optimum gearbox for efficient performance. This research focuses on the multi objective design of gear pairs and gearboxes using evolutionary computation. The gear pair and gearbox design problems considered in this paper have two different parameters as objective functions. Since all the parameters are on different scales, these factors are normalised to the same scale. The normalised objective function is obtained and it is called as Combined Objective Function (COF), the design optimisation of spur gear pair, three speed gearbox design is planned to be optimised by using COF. The objective functions and constraints considered in this work are given. The objective functions considered in the present study are: minimisation of weight and minimisation of centre distance. The constraints considered are: (a) The induced bending stress obtained from the formula based on bending strength should be lesser than or equal to the allowable bending stress, (b) The induced crushing stress obtained from the formula based on contact compressive strength should be lesser than or equal to the allowable crushing stress, (c) The centre distance should be greater than or equal to the value obtained from the formula based on contact compressive strength, and (d) The module should be greater than or equal to the value obtained from the formula based on bending strength.