Computational modeling and simulation can be used to optimize lightweight design by allowing engineers to virtually test different materials, structures, and designs without physically building prototypes. This enables them to quickly identify the most efficient and cost-effective lightweight solutions. By analyzing the performance of various designs under different conditions, engineers can fine-tune the design to meet specific requirements such as strength, durability, and weight reduction. This iterative process helps in optimizing lightweight design by minimizing material usage while maintaining structural integrity and performance.