Friction Coefficient Property And Its Relibility Anslysis In Pedestrian-Car Contact Collision Accident Reconstruction

Traffic accident reconstruction technique provides technical basis for the properties and responsibility confirmation of accident.As a typical kind of traffic accident,vehicle-pedestrian collision contains vehicle?pedestrian and ground which is a multi-body system and involves lots of variables,making it rather difficult to build the reconstruction model.Among all the input variables,pedestrian-ground friction coefficient is one of the most important one and has a decisive effect on the final computation result.This paper deeply investigates the nonlinear property of pedestrian-ground friction coefficient and conduct its reliability analysis based on a real traffic accident case.The main contents are listed as follows:Firstly,we propose the nonlinear pedestrian-ground friction coefficient model according to the contact friction theory and fiber assembly mechanics.A mathematical model is presented through computer simulation and theoretical derivation respectively,which provides instructions for the later reconstruction calculation and reliability analysis.Secondly,we completed field survey work of a real traffic accident.A CAD model is generated based on the site measurement data.A preliminary simulation is also given according the theory of multi-body dynamics.Then we conclude that the friction coefficient of pedestrian-ground produce the most significant impact on the simulation result through orthogonal experimental design method.Thirdly,we propose the method of reliability analysis model construction in pedestrian-vehicle collision based on the case above.Reliability analysis is also conducted in combination with the mathematical statistics theory.Finally,influences of pedestrian-ground friction coefficient on the initial velocity estimation is deeply investigated and measurement accuracy is also presented under the given initial velocity computation accuracy.Meanwhile our analysis also indicates that the vehicle in our case had a high probability of over speed upon pre-impact stage.