Development and validation of a thorax surrogate FE model for assessment of trauma due to high speed blunt impacts

Abstract

Without being able to evaluate blunt thoracic trauma in terms of an acceptable injury criterion, it is not possible to develop or validate non-lethal projectiles, bullet proof vests and chest protectors for sports personnel etc. In order for the assessment of the blunt trauma caused by high speed projectiles, a novel design of a mechanical surrogate of the thorax (Mechanical THOrax for Trauma Assessment: MTHOTA) was conceptualized. An iterative impact analyses in the virtual testing environment were carried out by impacting the finite element model of the mechanical thorax with 37 mm diameter, 100 mm long wooden baton weighing 140 grams (20 m/s and 40 m/s impact speeds) and 37 mm diameter, 28.5 mm long wooden baton weighing 30 grams with 60 m/s impact speed. From the output of every simulation, force dynamic response (force-time), deflection dynamic response (deflection-time) and force-deflection response were elicited and compared with the corresponding human response corridors developed by Wayne State University’s researchers. By suitably changing the design parameters of the mechanical surrogate, simulation iterations were continued till the responses were correlated with the human response corridors. Values of viscous criterion (VCmax), product of maximum chest deflection and the rate at which chest deforms, obtained from MTHOTA were in very good agreement with those obtained from the cadaveric test data. The methodology, concept and validation of the MTHOTA have been presented in this paper.