Topology and Cost Optimization Applied to Develop New Designs for a Monorail Structure

In this study, topology optimization was performed using a design methodology to minimize both the cost and weight of new designs for the skirt support structure of a monorail. Finite element analysis, topology optimization, manufacturing analysis, and a comparative cost analysis were conducted to develop novel lightweight designs. Verification of the designs was done by comparing them against the original structure.An analysis of the original structure was undertaken: structural analysis was performed using finite element analysis, and a cost breakdown was done based upon provided information by the industrial partner and the cost of the original structure. Manufacturing techniques used to create the original structure were identified.Topology optimization was performed in several iterations to converge on a quality result for the different designs. The large scale of the design space necessitated a new approach for creating detailed results from a large coarse mesh. Multiple loading cases and constraints were accounted for. The topology optimization results were then used to generate manufacturable designs. Different manufacturing methods were analyzed for the best trade-off between representation of the raw optimization result, structural performance, and cost efficiency.The final step was a cost analysis. The cost analysis was done comparatively to ensure the most qualitative and accurate comparison. The cost of the original structure and its manufacturing methods were used to build and validate the cost model. Features such as the number of parts, joints, bends, and length of cuts were used as metrics for the cost model.Two new, optimum designs resulted from this study: the first was 55% lighter than the original structure and 54% cheaper to manufacture, and the second was 53% lighter than the original structure and 58% cheaper to manufacture. These results greatly exceeded the initial target of 30% weight savings and 25% cost savings.