Design of the lower chassis of a monorail personal rapid transit (MPRT) car using the evolutionary structural optimization (ESO) method
The Evolutionary Structural Optimization (ESO) procedure was applied to the design of the lower chassis of a monorail personal rapid transit (MPRT) car. As part of the early stage development effort, ESO was used to identify a good topology of the lower chassis structure, which is effective in material usage, with lowly stressed material removed. The procedure started with building a three dimensional finite element model of the topology that occupies the design envelop, and lowly stressed elements were removed step by step during the ESO procedure. Multiple load cases concerning acceleration, deceleration, left turn, and right turn were analyzed separately, and a simple procedure dealing with multiple load cases was adopted. After 14 calculation increments, 80 of the initial material was removed. The resulting topology reveals a reasonable frame structure with rounded outer corners, triangular cantilever supports, and Michell style beam structures, suitable as a starting reference for the structure design of a MPRT.