Effect of Lightweight Design on Structural Dynamics and Energy Efficiency in Hydraulically Actuated Flexible Systems

Growing demands for environmental sustainability, energy efficiency, and enhanced automation are reshaping the design of heavy machinery, particularly hydraulic systems. This study introduces a workflow for the lightweight and energy efficient design of hydraulically actuated flexible multibody systems. The component of interest, lift boom was manufactured from RAEX 640 steel, was optimized using Ultra-High Strength Steel (UHSS). The structural characteristics of default and optimized lift boom were compared through linear structural analysis, and the impact on the system's energy efficiency was evaluated through a simulated work cycle. This optimization achieved a 21.9% reduction in weight when only in-plane moment capacity was considered. However, the reduced cross-sectional geometry, resulted in a 67% increase in tip deflection and eigenfrequency analysis revealed a shift of the critical first bending mode frequency from 104.6 Hz to 67.5 Hz. Flexible multibody dynamic simulations, including hydraulic actuation modeling, confirmed improved energy efficiency by 4% during an extension and by 7% during retraction phase. While the weight reduction benefits were clear, the findings underscore the importance of carefully balancing weight savings with mechanical performance criteria to ensure safe and efficient operation. The proposed workflow not only addresses current challenges in lightweight design for hydraulically actuated systems but also establishes a foundation for real-time digital twin development, supportingthe evolution of smart, energy-efficient heavy machinery.