Analytical Evaluation of Adaptive Seat Energy Absorber for Rotorcraft Semi-Active Crash Safety Seat Development

This research study focuses on the analytical evaluation of magneto-rheological (MR) dampers for enhanced occupant protection during vertical crash landings of a helicopter. The current state-of-the-art helicopter crew seat has passive safety mechanisms that are highly limited in their capability to optimally adapt to each type of crash scenario due to variations in both occupant weight and crash severity level. While passive crash energy absorbers work well for a single design condition (50th percentile male occupant and fixed crash severity level), they do not offer adequate protection across a broad spectrum of crash conditions by minimizing the load transmitted to the occupant. This study reports the development of a lumped-parameter human body model including lower leg in a seated posture for rotorcraft crash injury simulation. A physical model of lumped-parameter human body restrained on a crew seat was implemented in multi-body dynamics simulation software. For implementing control, a control algorithm was made to work with the multi-body dynamic model by running co-simulation. The injury criteria and tolerance levels for the biomechanical effects are discussed for each of the identified vulnerable body regions, such as the thoracic lumbar loads for different sized adults. The desired objective of this analytical model development is to develop a tool to study the performance of adaptive semi-active magnetorheological seat suspensions for rotorcraft occupant protection.