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The probability of traumatic brain injuries based on tissue-level reliability analysis

Hazay Máté, Bojtár Imre

Acta of Bioengineering and Biomechanics

2019

Vol. 21, no. 1

141--152

Motor vehicle crashes are one of the leading causes of traumatic brain injuries. Restraint systems of cars are evaluated by crash tests based on human tolerance data, however, the reliability of data currently used has been questioned several times in the literature due to the neglect of certain types of effects, injury types and uncertainties. Our main goal was to re-evaluate the currently applied risk curve by taking the previously neglected effects into account. Methods: In this paper, the probability of traumatic brain injury was determined by reliability analysis where different types of uncertainties are taken into account. The tissue-level response of the human brain in the case of frontal crashes was calculated by finite element analyses and the injury probability is determined by Monte Carlo simulations. Sensitivity analysis was also performed to identify which effects have considerable contribution to the injury risk. Results: Our results indicate a significantly larger injury risk than it is predicted by current safety standards. Accordingly, a new risk curve was constructed which follows a lognormal distribution with the following parameters: μLN = 6.5445 and LN = 1.1993. Sensitivity analysis confirmed that this difference primarily can be attributed to the rotational effects and tissue-level uncertainties. Conclusions: Results of the tissue-level reliability analysis enhance the belief that rotational effects are the primary cause of brain injuries. Accordingly, the use of a solely translational acceleration based injury metric contains several uncertainties which can lead to relatively high injury probabilities even if relatively small translational effects occur.

Numerical analysis of effects of IED side explosion on crew of lightarmoured wheeled vehicle

Panowicz R., Sybilski K., Kołodziejczyk D.

Journal of KONES

2011

Vol. 18, No. 4

331-339

The article presents numerical simulation of interaction of a pressure wave coming from detonation of an improvised explosive device on the crew of the ligtharmoured wheeled vehicle. There was analysed one of the typical scenario, namely the explosion on the side of the vehicle, which the army deals with during the stabilization missions of different kind. The objective of the presented numerical investigations was to examine the influence of dynamics impulse, according to mass of detonated charge, on the crew in the characteristic anthropometric points of the body. The numerical investigations presented in the present paper aimed at testing the influence of the mass of the detonated charge on the load to which the vehicle crew is subjected to. In order to meet this target, there were used capability of coupling between the compressed air, described with the use of equations of continuum mechanics by Euler, and the vehicle with the crew described with the same equations but formulated by Lagrange. Interaction of both of the centres was executed with the use of general coupling. To perform the analyses, Ls-Dyna software based on the finite element method with the algorithm of explicit integration in time was used. Development of a full-scale model of the special vehicle was preceded with the laboratory tests on the mechanical properties of armour steel applied for constructing the vehicles of this type.