چكيده به لاتين
While some studies have investigated astronaut head injury risks using head injury criteria (HIC), but a little research has been done to assess TBI risks using finite element astronaut head models which there are not available. The objective of this study is to analysis head injury risks in the astronaut using finite element human head model. For this purpose, first 3D finite element head model has been created in full details. The results of brain pressure in Nahum and Trosseille experiments have been used to validate FE head model. Next, Designing astronaut seat position has been done to preserve the safety of occupants under acceleration and impact loads of landing condition. So, initially, the astronaut’s dynamic response to the sustained loads while landing impact is at work were determined using astronaut multi-body dynamics. Next, the dynamic response of head to sustained loads was determined by applying the sustained loads to three-dimensional finite element model of the head. Subsequently, the probability of occupants’ being injured was assessed by changing seat angles and using neck injury index and head tissue injury criteria. Furthermore, a sensitivity analysis was carried out in order to evaluate the sensitivity of injuries to changed seat angles. Subsequently, comparing neck and head tissue injuries by changing occupant seat angle, an optimal seat location is proposed. Next, new head injury criteria have been developed to predict brain responses because of the limitation previous head injury index. For this purpose, head impacts were simulated for different magnitudes and directions of translational impact using finite element head model. Simulations were performed in order to evaluate pressure and stress responses by brain tissues due to changing the impact direction. Also, the effect of impact loads has been investigated on the brain responses in the sagittal, transverse, and frontal planes. Next, statistical analysis was used to develop new head injury criteria for predicting brain coup pressure, contrecoup pressure, and von Miss stress. Also, new head injury criteria have been proposed to predict rotational head injury. For this purpose, effect of rotational impact direction and magnitude on the brain injury have been evaluated using the SIMon model. Next, statistical analysis was used to develop new head injury criteria for predicting brain injury risk in rotational head impact.
