ABSTRACT
Objective To study the relationship between the severity of pedestrian head injury and the impact speeds, the vehicle types and the impact positions in pedestrian-vehicle accidents by computer simulation based on the real accident video. Methods A pedestrian-traffic accident with the video was reconstructed by the MADYMO multi-body dynamics software to obtain the initial and boundary conditions. Experimental impact simulations were conducted on different vehicles (car, SUV and minibus) and pedestrian impact positions (front, side and back structure) by different speeds (20, 30, 40, 50 and 60 km/h) to analyze head injuries, and the simulation results were validated by two real pedestrian-vehicle accidents. Results Not only the impact speed and the front structure influenced the pedestrian head injury severity, but also the impact position of pedestrian was an important factor. At the collision speed ≤30 km/h, the pedestrian head injury caused by the contact with the ground could be possibly more serious than the contact with the vehicle; while at the collision speed≥40 km/h, the pedestrian head injury was mainly caused by the contact with the vehicle. Conclusions The pedestrian traffic accident can be accurately reconstructed by using the real accident video to analyze the pedestrian head dynamic response. The severity of pedestrian head injuries can be effectively reduced by speed limitations on different types of vehicles at pedestrian traffic accident black-spots.
ABSTRACT
<p><b>OBJECTIVE</b>To analyze the injuries of motorcyclists involved in fatal motorcycle frontal crashes.</p><p><b>METHODS</b>A survey group involving multi-discipline experts was built to randomly collect data on fatal motorcycle frontal collision accidents that occurred in Chongqing during 2006-2010. The sampled information included medical or autopsy reports, blood alcohol concentration (BAC) level, helmet use, accident witness, field sketch as well as field photos. The motorcyclist injuries were scored according to the Abbreviated Injury Scale (AIS) 2005. The involved riders with a BAC level larger than or equal to 20 mg/ml were attributed to alcohol use. Data were processed statistically with nonparametric test via software SPSS 11.0.</p><p><b>RESULTS</b>A total of 86 fatal motorcycle frontal crashes were sampled and further analyzed. The age of motorcyclists enrolled in this investigation showed nominal distribution and the middle-aged (30-39 years) occupied the highest percentage of fatalities. There were only 14 motorcyclists (16.3%) wearing helmets at the moment of collision. And 12.8% of these motorcyclist crashes were attributable to alcohol use. Impact injury was the main fatal cause, accounting for 72% of motorcyclist deaths, followed by tumbling injury (26%) and run-over (2%). Respectively 84%, 22% and 19% of motorcyclists who sustained head, chest and abdominal trauma died. Extremity injury was the most frequently observed injury type.</p><p><b>CONCLUSIONS</b>This investigation is helpful to build accident prevention programs and develop protection devices which may effectively mitigate injuries and prevent deaths following motorcycle frontal collision accidents. Further investigations on motorcycle collision accidents are still needed.</p>
Subject(s)
Humans , Abdominal Injuries , Accidents, Traffic , China , Craniocerebral Trauma , Head Protective Devices , MotorcyclesABSTRACT
Objective to research the mechanical style(compressive or tensile force)of the key site of brain tissue in brain deceleration impact.Method a transparent physical brain model with air bubbles was built and loaded on an upright brain decaler ation impacting expedmentel platform.Then,the moveable platform was made a free fall from a height of 400mm and impacted on the fixed platform,and the whole deceleration impacting process was recorded by a high-speed video camera.Using the serial pictures analyzing Software,the length change of the long ads(vertical to the impacting direction)and the short axis(in the impacting di-rection)of the air bubbles were analyzed and calculated.Result the length change of the long axis of air bub-ble with in site coup was smallerthan the absolute value of that of the short axis;while with the air bubble in the contrecoup site,the length change of the long axis was bigger than the absolute value of the short axis.Conclusions the results showed that the air bubble in the coup site mainly suffered from the tensile force vertical to the impacting direction and the air bubble in the contrecoup site mainly suffered from the compres-sive force in the impacting direction.Since the propeny of tensile resistance of the brain tissue is inferior to the property of compressive resistance of the brain tissue, the injury is often easier to occur in the contrecoup site than in coup site. The results were of significance to the research of biomechanical mechanism, diagnosis and prevention of the brain deceleration impacting injury.
ABSTRACT
Objective to research the mechanical style(compressive or tensile force)of the key site of brain tissue in brain deceleration impact.Method a transparent physical brain model with air bubbles was built and loaded on an upright brain decaler ation impacting expedmentel platform.Then,the moveable platform was made a free fall from a height of 400mm and impacted on the fixed platform,and the whole deceleration impacting process was recorded by a high-speed video camera.Using the serial pictures analyzing Software,the length change of the long ads(vertical to the impacting direction)and the short axis(in the impacting di-rection)of the air bubbles were analyzed and calculated.Result the length change of the long axis of air bub-ble with in site coup was smallerthan the absolute value of that of the short axis;while with the air bubble in the contrecoup site,the length change of the long axis was bigger than the absolute value of the short axis.Conclusions the results showed that the air bubble in the coup site mainly suffered from the tensile force vertical to the impacting direction and the air bubble in the contrecoup site mainly suffered from the compres-sive force in the impacting direction.Since the propeny of tensile resistance of the brain tissue is inferior to the property of compressive resistance of the brain tissue, the injury is often easier to occur in the contrecoup site than in coup site. The results were of significance to the research of biomechanical mechanism, diagnosis and prevention of the brain deceleration impacting injury.