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Objective To investigate the characteristics of personal injuries in motorcycle accidents in Chongqing area to provide the reliable information and reference basis for reducing the injury and death risk of the motorcycle accidents.Methods Two hundreds and thirteen cases of motorcycle traffic accident occurred in Chongqing area from January 2015 to June 2016 were deeply collected,the collected contents included the basicinformation,driver information and personal injury,etc.Then accident data were statistically analyzed.Results The death rate of motorcycle drivers was higher than that of the pillion passengers.The death causes of craniocerebral injuries and craniocerebral injuries complicating thoracic and abdominal organ injuries accounted for 58.8％ and 20 ％ respectively,the proportions of head and neck,chest and back,lower extremity,upper extremity,abdominal and pelvic part and perineal part MAIS ≥2 were 71％,59％,33％,25％,20％ and 7％ respectively.The perineal injury rate of motorcycle drivers was higher than that of the pillion passengers.The ratio of occurrence rates between lower extremity fracture to upper extremity fracture was 1.8 ∶ 1,the persons in motorcycles-trucks accidents were easier to suffer from vehicle crushing.Conclusion Head and chest injuries are important causes leading to motorcycle drivers and pillion passengers' death and injury.The perineal injury can serve as an important basis for identifying the drivers and pillion passengers in partial motorcycle accidents.
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Objective In order to fully reconstruct the accident by utilizing pedestrian injuries information gained from the car-pedestrian collision, a new method based on finite element simulation and genetic neural network to deduce the car-pedestrian collision parameters in reverse is proposed. Methods Crash simulations from different contact angles (back, left, front, right) at different impact speeds (25, 40, 55 km/h) were conducted by using Hyperworks and LS-DYNA, so as to obtain the head injury criterion (HIC) value and the maximum velocity of the thoracic wall. According to the criteria of injury biomechanics, the severities of the pedestrian head and thorax and corresponding injury locations were analyzed and set as predictors, and the predictive values of collision parameters were then acquired by using genetic neural network. Finally, this method was verified by two car-pedestrian accidents with the video and exact collision parameters. Results For both cases of the car-pedestrian accidents, the car speeds at the collision of pedestrian were 54 and 49 km/h, respectively, and the car-pedestrian contact angles were both 180°. While according to the pedestrian injuries information, the predictive values of the car speeds at the collision of pedestrian were 51 and 43 km/h, and the predictive values of the car-pedestrian contact angles were 184° and 169°, respectively. The reconstruction accuracies of two cases were 0.94 and 0.88. Conclusions The proposed method in the study can be used to predict car-pedestrian collision parameters efficiently and accurately by utilizing the pedestrian injuries information, which provides a new method for cause analysis and responsibility recognition, as well as theoretical references for the treatment and protection of head and thoracic injuries occurred in the car-pedestrian collision.
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<p><b>OBJECTIVE</b>To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.</p><p><b>METHODS</b>In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.</p><p><b>RESULTS</b>In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.</p><p><b>CONCLUSIONS</b>The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism.</p>
Subject(s)
Humans , Biomechanical Phenomena , Brain Injuries , Finite Element Analysis , Intracranial Pressure , ManikinsABSTRACT
<p><b>OBJECTIVE</b>To explore the relationship between the collision parameters of vehicle and the pedestrian thorax injury by establishing the chest simulation models in car-pedestrian collision at different velocities and angles.</p><p><b>METHODS</b>87 cases of vehicle-to-pedestrian accidents, with detailed injury information and determined vehicle impact parameters, were included. The severity of injury was scaled in line with the Abbreviated Injury Scale (AIS). The chest biomechanical response parameters and change characteristics were obtained by using Hyperworks and LS-DYNA computing. Simulation analysis was applied to compare the characteristics of injuries.</p><p><b>RESULTS</b>When impact velocities at 25, 40 and 55 km/h, respectively, 1) the maximum values of thorax velocity criterion (VC) were for 0.29, 0.83 and 2.58 m/s; and at the same collision velocity, the thorax VC from the impact on pedestrian's front was successively greater than on his back and on his side; 2) the maximum values of peak stress on ribs were 154, 177 and 209 MPa; and at the same velocity, peak stress values on ribs from the impact on pedestrian's side were greater than on his front and his back.</p><p><b>CONCLUSION</b>There is a positive correlation between the severity and risk of thorax injury and the collision velocity and angle of car-thorax crashes. At the same velocity, it is of greater damage risk when the soft tissue of thorax under a front impact; and there is also a greater risk of ribs fracture under a side impact of the thorax. This result is of vital significance for diagnosis and protection of thorax collision injuries.</p>