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.
A guided missile is a weapon system used in the interception of a ballistic missile using kinetic energy of a kill vehicle. The DACS (Divert and Attitude Control System) is a quick reaction propulsion system and subsystem of a kill vehicle that provides control over positions of a kill vehicle. The DACS allows for the interception of its target with greater accuracy and reliability. A Kill vehicle needs to move at high speed in a bid to intercept a ballistic missile after detecting a target. Thus, the weight reduction design of DACs system is required. The DACS operates under high temperature and pressure environment. In this study, one-way FSI (Fluid and Structure Interaction) analysis were conducted for various types of weight reduction valve model to validate its robustness. Through this process, we suggest an optimized weight reduction valve model