Current seat belt systems use a force limiter mechanism. However, they have the disadvantage of being unable to accommodate a wide range of speeds, as they provide constant performance regardless of speed. The purpose of this study is to reduce restraint forces across a wide range of speeds by developing a semi-active vehicle seatbelt system using a Magneto-Rheological (MR) shock absorber. The effect of system response delay is also considered. In this study, a vehicle model for the sled test is proposed for simulation and MR shock absorber optimization. In the first step, we optimized the gap of the MR valve and the initial pressure of the gas chamber. Then, the current applied to the coil is fine-tuned by minimizing restraint forces for various frontal crash speeds. The results show that the seat belt system with an MR shock absorber can significantly reduce restraint forces for various crash speeds. In all cases-Case 1, Case 2, and Case 3-by optimizing the current value I, the maximum chest restraint force was reduced by approximately 13.6% to 52.5% compared to using only the seatbelt.

seatbelt, optimization, MR Fluid, Seatbelt Restraint Forces, MR Damper, Semi-active seatbelt