This paper reports the results of multi-body numerical simulation of a vehicle crash with a teenager pedestrian. A previous technique utilized for adult pedestrian impact is applied. The work starts with the determination of the masses for the various segments of the body of a teenager with a total mass of 45 kg and then switches to the construction of the dummy and the middle-class vehicle in the Visual Nastran environment. Simulations are performed for both frontal impacts and lateral impacts, when the vehicle is travelling at a constant speed and when the vehicle is braking, following the Euro NCAP rules on the subject. The results are analysed by calculating the values of the head injury criterion for the head and the values of the thoracic trauma index and 3 ms criterion for the chest; the injuries are assessed according to the current interpretation. Abbreviated injury scale curves are used to determine the dangerousness of the impact. Finally, the results are close to those obtained by applying the same technique to an adult pedestrian and other available data in the literature for an adult or a child.
This work studies the teenage pedestrian-sport utility vehicle (SUV) crash; injury to the vital parts of the body, such as the head and chest, and to the femur is evaluated. More advanced injury criteria are applied, as provided in the rules. The multibody technique is applied by making use of SimWise software and of the teenager anthropomorphic model, the use of which is now consolidated. Head injury criterion (HIC) is used for the head, thoracic trauma index (TTI) criterion for the thorax in the case of side impact and 3 ms criterion in the case of frontal impact, while the force criterion is used for the femur. Both the TTI and femur load evaluation require non-substantial modifications of the dummy, by insertion of sensors for the measurement of the acceleration of the 4th rib and the 12th vertebra and two very thin plates at the knees for the correct individuation of the contact point with the vehicle bumper. Particular attention is paid to the front shape of the vehicle, concluding that the SUV examined in this paper is less dangerous than the sedan studied in a previous work, since its frontal dimensions (bonnet angle, bumper height and bonnet height) are more advantageous. However the teenage pedestrian in a lateral position is less prone to injuries in the head and chest, with respect to the frontal position; the pedestrian's position has little influence on femur damage. Furthermore, the braking of the vehicle reduces the possibility of crash fatality. In conclusion, a theoretical approach is shown, to highlight the influence of the vehicle mass on the pedestrian speed after the impact.
This work studies the impact conditions between the adolescent pedestrian and the bus focusing on head and chest injury. The injury to the head is analyzed using both the Head Injury Criterion (HIC) 36 and the HIC15 parameters as established by the most advanced legislation and comparing the risk probability Abbreviated Injury Scale (AIS3+) and AIS4+. The parameter HIC15 gives a higher probability of risk with lower values, and therefore it can be considered more conservative. Moreover, the study of chest injury is performed with two different biomechanical parameters: the Thoracic Trauma Index (TTI) and the TTI(d); the last neglects the pedestrian mass. The results indicate that the parameters are equivalent for the assessment of chest injury. Instead the front pedestrian collision is characterized by 3 ms criterion. The results comparison with those obtained previously with other types of vehicles shows that, in all cases, the impact with the bus is most dangerous for the teenage pedestrian because of the higher values of the biomechanical parameters. Finally, the influence of the vehicle mass has been investigated, emphasizing how it cannot be neglected a priori. Numerical analysis results are in very good agreement with the results carried out experimentally, from several authors, in real accidents where buses are involved.
Palermo University (Italy) does not participate directly in the FSAE competition, but lets its students compete "virtually" by organizing laboratories and working groups in order to design and simulate a car chassis that meets the regulations, of Formula Student in particular. These works, which flow into the students' graduate theses, are often placed together with a view to continuity and constant optimization and improvement. The purpose of this paper is to pick up the work done in the design of an automotive chassis, and to carry it out by shifting the focus no longer on the static resistance of the structure, but on the influence it has on the dynamic behavior of the vehicle. To do this, a long work of reconstruction of past models was carried out, adding to them what was necessary to complete the definition of an equivalent vehicle, and using materials and technologies used in the automotive industry. The subsequent series of simulations on three vehicles with different chassis and the comparison of the results have shown how at present the aluminum alloy frame is the preferable one over the steel and carbon alloy one.
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