System Level Crash Sled Simulations forEvaluating Helicopter Adaptive Seat Damper

This research study focuses on the finite-element based nonlinear dynamic model development and analysis for virtual evaluation of adaptive seat 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 finite-element based seat-occupant system level model using LS-DYNA3D for rotorcraft crash injury simulation. This finite element simulation model of a seated occupant with five-point belt and stroking seat is used to study occupant kinematics and spinal injury assessments to support crash sled evaluations of seat energy absorbers. The injury criteria and tolerance levels for the biomechanical effects are discussed for each of the adult-sized occupants with respect to thoracic lumbar loads. The desired objective of this analytical model development is to develop an analysis tool to study the performance effectiveness of adaptive seat energy absorbers for enhancing rotorcraft occupant crash protection