Optimization Of Underbody Blast Energy-Attenuating Seat Mechanisms Using Modified Madymo Hybrid Iii And Human Body Models
Energy attenuating (EA) blast seats, although not new to the market, have not been fully characterized with respect to energy attenuation capability and the resulting effects on occupant protection. EA seats utilize stroking mechanisms to absorb energy and reduce the vertical forces imparted on the occupant’s pelvis and lower spine complex. Although a variety of EA seats are available on the market, the fundamental question behind how to optimize the force and deflection rates of the EA mechanisms to effectively reduce occupant injury has not yet been answered. Using modeling and simulation techniques, this research developed a tool to determine optimal force and deflection profiles to reduce pelvis and lower spine injuries experienced by Warfighters in underbody blast events using a generic seat model with MAthematical DYnamic MOdels (MADYMO, TASS International, Inc.) software. This optimizing tool can be shared with EA seat manufacturers and applied to military seat development efforts for EA mechanisms for a given occupant and designated blast severity.
Using Hybrid III anthropomorphic test device (ATD) and post-mortem human surrogate (PMHS) data from the University of Virginia in a sub-injurious Condition A (4 m/s seat velocity) and injurious Condition B (10 m/s seat velocity), this research is summarized in the following specific aims:
1. Hybrid III Rigid Seat Validation: Validate Hybrid III ATD model response in rigid seat in sub-injurious Condition A.
2. Human Body Model Rigid Seat Validation:
a. Condition A: Validate human body model response with PMHS in rigid seat for sub-injurious Condition A.
b. Condition B: Validate human body model response in rigid seat with injurious Condition B.
3. Seat Optimization with Human Body Model: Vary force-deflection properties of EA seat mechanism and run parametric sensitivity study with human body model to reduce acceleration in pelvis and forces in lumbar region for injurious Condition B.
4. Hybrid III Output from Optimized Seat: Verify Hybrid III response with injurious Condition B in rigid seat, then apply optimal EA properties to the seat and determine acceleration in pelvis and lower spine forces for Hybrid III ATD model for Condition B as target injury criteria for seat manufacturers.