In view of the relatively serious situation of chest injuries in current vehicle accidents, this study aims to determine the chest injuries characteristics in frontal vehicle collisions under different overlaps. The frontal impact simulation was first established and conducted based on the latest THOR dummy model with different overlaps. By comparing chest dynamic output indicators under three different overlap rates in frontal impact conditions, the relationship between chest injuries and collision overlap rates was analyzed in terms of the chest deflection and stress/strain distribution. Results show that changes of the thoracic stress/strain distribution and the amplitude of chest deflection are more sensitive to frontal impact load under a great impact overlap. In the kinematics analysis, there is a significant twist along the seatbelt route to the occupant’s chest. The changes of the chest deflection and stress/strain based on the design parameter changes at different overlap rates are consistent, and the highest injury risk is captured in the ribcage structure of mid-chest in full frontal impact. The research results can provide a reference for the optimal design of the constraint system for the future.
The oblique impact is the second most common frontal impact, in which both the forward and lateral accelerations are applied to the occupant. It is noticed that the oblique impact is a primary source of serious injuries, in which the chest injuries are mostly fatal through the statistics of traffic accidents. This study aims to investigate the characteristics of the occupant’s chest injury in the frontal oblique impact. First, a model with a sled and a Test Human Occupant Restraint (THOR) dummy is established. Second, an acceleration curve with a peak of 9.0 g is applied to the sled. Then 11 sets of simulations with different impact angles and belt peak loads are conducted to evaluate the occupant’s chest responses. Results indicate that there is a negative correlation between belt peak force and injury outcomes, while there is a weak correlation between chest injury and impact angle. With the increase of the belt force limit, the chest deflection at Lower Left (LL) would increase by 37.9%, and the acceleration at LL would increase by 23.1%. Meanwhile, the Viscous Criterion (VC) at LL would increase by 61.4%. However, the relationship between the impact angle and injury drawn by VC and acceleration is inconsistent. Additionally, in all simulations, the maximum deflections are captured at the LL, while the maximum VCs happens at Upper Right (UR) or LL. It is demonstrated that a seatbelt with a lower peak force is friendly to the occupant’s chest under all the impact angles. This study can provide a reference to the study of chest injury in the oblique impact.
Abstract.This paper discussed the problem that parameters of bone external fixator are difficult to calculate in the practical application. Positive solution is described in detail. We used MATLAB software to make simulation experiment. The innovation lies the development idea of using inverse position to verify the accuracy of positive solution. Forward displacement analysis was mainly developed using analytical method, which has many advantages, such as small dependence to the inverse solution and the higher precision. With further software development, we will have the algorithms; research model and interface program connected and form high precision smart compliance multifunctional bone external fixator products, which will greatly enhance the overall level of bone external fixation technology and clinical application treatment.
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