Simulation of Pressure Wave Propagation in the Brain

Abstract

Stunning quality in the slaughter house varies. A growing concern for the animals well-being and the safety of slaughter house personal call for improved slaughtering techniques. The main aim of this thesis is to establish whether or not the external parameters of a bolt stun can be altered to improve the stunning quality of animals before a debleeding.To meet this aim three sub studies, using finite element models and the solver LS-DYNA, were carried out. First, experiments in which a bolt entered gel bodies were reproduced to suggest modeling strategy and contact settings. An ALE method for the modeling was determined to be the most appropriate. Second, a finite element model of a rat brain was adopted and evaluated. Past experiments, carried out on rats, in which pressures were recorded in the brain during simulated stunning, served as evaluation data. Some problem areas in fitting the FE model to this purpose were identified, mainly areas where pressure transfer was hindered. Finally, a parameter study was carried out to study the effect of external bolt parameters in intra cranial pressure distribution. The simulation results from the parameter study indicate that a change of speed, position and angle could greatly affect how the pressure propagates through the brain tissue, and thereby increase the quality of the animal stunning.