Accident Reconstruction Of Inner-bus And Safety Design Improvement

China’s traffic accidents occur more frequently, show great casualtiesand property loss and so on, with a big improvement space comparedwith the developed countries in the traffic safety aspects. In all types ofaccidents, quantities serious accidents causing mass death and casualtyhave the most severe bad influence, which seriously restrict the socialharmony and development. While bus accidents account for a largeproportion, so it’s urgent to carry out related research. At present,computer numerical simulation technology has become the main methodto study accidents and its intuitive visual process reconstruction providesthe scientific basis for accidents analysis and prevention.This paper analyzes the domestic and foreign bus collision accidentsresearch, sums up the relevant standards and the human body injurybiomechanics evaluation index and summarizes the actual characteristicsof this kind of traffic accident. According to the numerical simulation ofinner-bus collision, first analyzes basic calculation theory of bus collisionreconstruction, compares their respective advantages of themulti-rigid-body method and finite element method in collisionsimulation calculation considering the balance between efficiency andaccuracy. Second summarizes human injury characteristics in the processof collision through survey counts. Finally analyzes the structure ofdigital dummy and its collision contact forms, proposes a method to buildbus-occupant model and establishes the bus-sitting crew system andcoach bus-pedestal crew system model.In order to evaluate safety risk of sitting crew in the bus as anexample, selects seven seats inside located in different positions as representatives to perform numerical simulation in emergency brakesituation and analyzes the movements of the crew, the collision bodyparts, the human body damage index etc. Then induce injury parts andforms of sitting crew. According to the damage index of tolerance limit,the damage degree is evaluated to conclude that sitting crew has a safetyrisk.In view of requirements of bus safety, this paper puts forwardthree-point simple belt as the basic constraint system in the bus withreference to two-point safety belt in the coach bus and discusses theinfluence of belt fabric stiffness characteristics to reduce the crew’sdamage. One thing to note is that each seat’s space environment isdifferent needing to match belts according to the specific situation.Through adding right seat belts, the crew’s head and neck injury reducesgreatly while chest injury maintain within the limit of tolerance, so as toreduce injury risk of occupants effectively. In addition, fixing the baffle inthe position of hand rail is also an effective kind of improvementmeasures which can hinder the crew from multiple impacts with parts inthe bus such as steps and so on. Finally, pedestal safety in the coach busis discussed and safety risk is found in emergency braking andacceleration process, providing numerical reference to relateddepartments.