Experimental Study On The Distance Of Scatters Caused By Vehicle Crash

The traffic accident is a worldwide problem, a trouble in all countries of the world since thecar appears. The traffic accident in China is more serious than any other countries in the world,mainly reflected in two aspects: one is the number of traffic accidents are more; the other iscasualties of traffic accidents are more. According to statistics, China has about900000people diein traffic accidents in the past ten years (2002~2011).Accidents not only caused casualties and property losses, but also caused many civil andcriminal disputes. So, it is a urgent problem for our government to reconstruct traffic accidentprocess and determine responsibility for the accident.Traffic accident reconstruction is that reconstruct the process of the accident in time andspace, According to information of Accident scene and using kinetics and dynamics methods.Debris, as the most important information at the traffic accident scene, includes much importantinformation of accident. So debris is the key factor for accident reconstruction.Debris of traffic accident includes Headlamps fragments, windscreen fragments, sheddingparts of vehicle, human body, sand, clod, bicycle, motor bicycle, stowage, leaked liquid, etc.At the moment, the research on debris of a large mass includes the analysis of kineticsand dynamics, and on debris of a small mass includes kinetics and distribution, etc. With thedevelopment of technology, the early research has inevitable shows its limitations. So, furtherresearch on debris of traffic accidents is necessary.Base on the foreign early research about crash debris, crash debris included throwing,bouncing, rolling and sliding. Assume that crash debris is elastic-plastic materials; ignore debrisshape’s influence of the movement, then research the throwing mathematical model. About thedebris of distributing fields’ characteristic, choose thrown distance of fastest, center, nearest thatmay represent distributing fields’ characteristic for study.In this paper，ignore the influence of debris shape, material, road conditions and debrisresistance of breaking away when studying. Therefore, the thrown distance that calculates throughtheory mathematical model is different from the actual mathematical model. So we introducecorrection coefficient with the theory mathematical model in this paper.In order to get the correction coefficient of theoretical model, we carried out headlight collision test. Designed crash device; done many experiments in dry asphalt road through changeinitial speed, headlight type, and Initial height. Vehicle dynamic parameter in tests is record byvc2000pc accelerometer. Observe debris’ distribution field after the tests. Measure the fastestthrown distance, center thrown distance, and nearest thrown distance through tape. Analyses andprocesses test data. Work out correction coefficient.Because most of the crash debris are elastic-plastic material, in this paper we analysis bouncecharacteristic of elastic-plastic material through Ansys/Ls-Dyna software. Analysis three cases, thefirst is that initial height and initial angle of thrown object are determined, test the relation ofspeed rebound coefficient and angle rebound coefficient with initial velocity; the second is thatinitial velocity and initial angle of thrown object are determined, test the relation of speed reboundcoefficient and angle rebound coefficient with initial height; the tired is that initial velocity andinitial height of thrown object are determined, test the relation of speed rebound coefficient andangle rebound coefficient with initial angle.