This study evaluates the load and moment characteristics of composite leaf springs used in the front suspension of a 4.0- ton gross vehicle weight (GVW) light commercial van through CarSim-based vehicle dynamics simulations. Carbon fiber composite (CFC), glass fiber composite (GFC), and hybrid composite (HC, carbon 20%: glass 80%) leaf springs were fabricated with identical geometry using a prepreg compression molding (PCM) process. Spring constants obtained from four-point bending tests were incorporated into the vehicle dynamics model. Dynamic responses were analyzed under flatroad driving, acceleration, braking, cornering, and speed bump conditions. The results indicate that the GFC leaf spring achieved a 61.5% weight reduction compared to a conventional steel spring while maintaining equivalent vertical load and roll moment responses. The HC exhibited improved roll suppression and pitch stability, whereas the CFC demonstrated excessively high stiffness, limiting its applicability to heavy-duty vehicles. Furthermore, the GFC maintained stable dynamic performance after low-velocity impact damage of 20 and 80 J, with stiffness remaining within ±5% of the steel reference. These findings confirm that composite leaf springs, particularly those made from glass fiber composites, provide a practical and durable alternative to steel leaf springs for light commercial vehicle suspension systems.
The Flywheel Energy Storage System (FESS) stores the electric energy into the rotational kinetic energy of the rotor. The FESS uses housing components so that the rotor spins inside the housing where the vacuum is maintained. Thus, the housing component is exposed to the load due to this pressure difference, and designing the housing that can efficiently support this load is crucial. Meanwhile, in the situation wherein the rotor lifting force is blocked, the rotor drops and damages the system. Thus, it is necessary to equip a structure capable of supporting the corresponding impact of the rotor drop. In this study, the design of the housing components is described by considering the structural robustness of the housing components, under the atmospheric pressure and impact of the rotor drop. For the pressure load, structural analysis was conducted following the different housing lid shapes: concave, convex, and flat. For the impact of the rotor drop, the structural analysis was conducted following the different terminal velocities of the rotating rotor. As a result, the designed housing components comprise a concave housing lid and the safety suspension 1 mm beneath the rotor. Considering the results, it operates stably under the conditions stated above.
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