Multi-objective optimization of centre locking hub bolt of automobile wheel under conflicting objectives

The need for quick detachment and replacement of tires in the motorsports and Formula racing industry is achieved by the use of Central Locking (CL) hub bolt. The present work implements the concept of CL hub bolt for Formula Student Car where the use the conventional 4-bolt wheel hubs is more prevalent among many student teams. This modification leads to a simplified version for a Formula Student Car design in which the time for wheel assembly considerably reduces. The present work focuses on the optimization of a CL hub bolt design for Formula Student Car. The bolt design variables are constrained to satisfy two requirements which are conflicting: first, to minimize weight by maintaining stresses within the limits governed by different materials and second, to restrict bending deflection of the bolt. This situation demands use of the multi-objective optimization techniques. The bounded objective function method and utility function method based on stochastic random search are used for optimizing the design variables and to achieve the best balance between the values of weight and deflection. The results from two methods are presented in the form of variation in weight and deflection against the bounds and weighting factor respectively for bounded objective function method and utility function method. The selection of parameters like bounds and weighting factor is observed to be an important criterion in multi-objective optimization. An approach to help in the selection process is established based on several iterations. The developed approach allows users to fine-tune the results to achieve the desired values within the set constraints.