Dynamics Simulations And Experimental Study On Debris In Automotive Crashes

The number of traffic accidents and traffic fatalities and injuries involvingmotor vehicles has been rising steadily in recent years. Motor vehicle trafficaccidents can cause serious physical and economic damage. The traffic accident inChina is more austere than any other countries in the world, and all kinds ofaccident parameters are higher. For the serious traffic accident actuality, thegovernment and correlative organizations have to take some measures. Someadvanced scientific technologies are continuously applied to prevent the accident inthe research organization. According to the substance left and the vehicleinformation in the accident scene, accident reconstruction indicates the process ofthe accident in time and space, and the correlative parameters of the vehicle beforeaccident are worked out. Therefore, the reasons are further analyzed by usingrelative methods.Information reserved in traffic accident scene is important evidence and thekey factor for accident reconstruction. Trace and material evidences left in thetraffic accident can prove the truth, which are the goods, substance and trace,including the vehicle, human body, road surface, fixity, attachment, debris, as wellas the various trajectories in the spot. Debris means the objects or substance left inthe traffic accident spot, which can be taken to show the fact of the accident, suchas damaged parts, particles of glass, fragments of paint, pieces of rubber, stowage,shiver of soil and sand, accessory, organs of the human thrown on the ground, bark,branch, cement and stone shiver left on the ground which was bumped or scrapedby other objects, etc.At present, the research on debris mainly includes the analysis of kinetics anddynamics, collision of pedestrians, test of distributing fields based on statistics, etc.However, the early research has not adapted well to the rapid development ofautomotive technology, and the influencing factors of traffic accident are complex.Thus, further research on debris of accidents is necessary. The following aspectswill be studied:Pedestrians, bicycles and bicyclists are defined as debris to enrich thedefinition of the debris. Models of vehicle/pedestrian collisions and trajectoryobjects throw distance in the worlds are introduced, and at the same time the paperput forward the concept of distributing fields based on statistics. Moreover,experiments made by foreign scholars on pieces of glass thrown are analyzedcomprehensively, and concrete examples are also presented according to models oftangent dynamics.The representative debris is analyzed owing to debris' diversity at the trafficscene. The experiment on simulation impact of automotive headlight is done andthe data of the experiment is analyzed in the paper, combined with the programmwhich displays the form characteristic of distributing fields of the headlight piecesby VC2000PC. Meanwhile, the parameters are selected, which have specificphysical significance, representing the whole characteristic of distributing fields ofthe pieces. Correlative models of accident reconstruction are established for a newscientific appraisal technique.The experiment of accident debris scattered is made for the first time in thispaper. Typical debris selected as the test object in accident scene, equipment fordebris is set up and vehicle crash test simulation is performed compared with thereal accident conditions. The correlative running parameters of the test vehicle arereal-time measured by VC3000 accelerometer. Distributing characteristics ofunattached debris and drossy debris are analyzed. The relative motion coursebetween debris and vehicle is analyzed by multi-body dynamics software ADAMS.The relationship between characteristic parameters of debris distributing fields andspeeds of motor vehicle crash is established.Dummy collision test ground of vehicle/pedestrians is simulated byPC-Crash. Pedestrians collision are divided into two traditional types, which arecollisions between rear and side of pedestrians with front of automobilesrespectivly, the cuniform head vehicles rated highly in the market are choosen asimpact vehicles. The throw distance model of the first dropped spot in pedestrians'collision is put forward for the first time. The position, which pedestrian relativingto the front of vehicle, has influence on throw distance before collision. Thekinematics of pedestrians, bicycles and bicyclists in the process of colliding isfuther analyzed in the paper. Vehicle/pedestrians collision model, high collisionmodel, vehicle/pedestrians scrape collision model and vehicle/bicyclists collisionmodel are established according to the simulating test data. The feasibility and theeffectiveness of the model are validated by comparing the model brought in thispaper with the foreign congener models.For tangency calculating, the finite element analysis method is a good choice,if object distortion was considered. Movement and contact of the sphere issimulated and analyzed by ADAMS and LS-DYNA. Simulation model of throwmovement of the sphere is set up in ADAMS, and the courses of the spheremovements are analyzed under the original conditions, including movements of thesphere, the separation from the debris to loading desk. The model of the spheredepreciation is set up in LS-DYNA, changing the displacement, velocity andacceleration in the course from the sphere touching the ground, correspondingparameters curve is got under static and dynamic friction coefficients, figures ofdisplacement, velocity, acceleration and stress-change are brought meanwhile.