Lightweight design of a seat module assembly for a robotic arm amusement ride system using topology optimization

This paper presents a methodology to design a lightweight seat module assembly (SMA) for a robotic arm amusement ride, often used in dark rides. Typical SMA designs begin with a welded metal frame, and the exterior shell serves only as a non-structural cover, resulting in stress concentrations and excess weight. The proposed methodology introduces a bottom-up process that integrates topology optimization at the outset, enabling the outer shell to function as a primary load path and subsequently identifies the ideal configuration for internal secondary framing by utilizing manufacturing constraints. This approach is further enhanced by adopting fiber-reinforced polymers as the structural material, leveraging their high stiffness-to-weight ratio to replace conventional metallic designs. Multiple manufacturing-specific interpretations of the optimized design were explored to evaluate feasibility, including extrusion and tubing based approaches. Finite element analysis of the final design under high intensity load cases verified that stress and displacement constraints were satisfied. This methodology achieved a 36% reduction in mass while increasing capacity from four to five seats, corresponding to a 49% reduction in mass per seat compared to the metallic baseline. The bottom-up process allowed for an integrated design approach, where the outer shell of the SMA was designed first, featuring a novel curved geometry which minimizes stress concentrations while contributing to the overall structural stiffness, followed by the integration of the internal structure. This methodology demonstrates a new direction for SMA design in the themed entertainment industry, where load path driven, composite-first approaches can reduce weight while increasing occupant capacity.