Optimization and Sensitivity Analysis of Brake Rotor Frequencies

In this paper, an application of shape optimization to the design of an automotive ventilated disc brake rotor is investigated and a methodology is presented. The objective is to utilize a commercial finite element optimization software to alter the modal characteristics of the brake rotor as a potential solution to brake squeal issues. A comparison is made between the traditional process of rotor design and analysis and one using optimization. The frequencies and mode shapes of the brake rotor are calculated using a finite element model and the results are compared to test results to establish correlation. Geometric features are selected as design variables, and shape optimization is carried out using Altair Optistruct software to increase the frequency separation between the critical modes while constraining the frequency separation between other selected modes. The sensitivities of the responses to the different shape design variables are calculated and studied to understand the effect of each design variable. Discussion is made on the advantages and disadvantages of using optimization for rotor design, considerations for modeling, design variable and constraint selection, and using the results to make design changes. The results show that this methodology can be successfully applied to brake rotor design analysis for frequency tuning and has the potential to reduce product development time and increase efficiency by eliminating the trial and error process that is commonly followed in the brake industry today.