PEDESTRIAN IMPACT AND RUN OVER USING A MULTIBODY SIMULATION TOOL

The simulation of impact and run over of a pedestrian by a bus is presented here to demonstrate the fundamentals of the use of integrated multibody based methodologies as accident reconstruction tools. The equations of motion for the pedestrian and bus models are generated in a systematic way and described using a set of natural coordinates. These equations are solved using the augmented Lagrange formulation which accounts for the existence of redundant kinematic constraint equations, arising from the choice of coordinates used in most of the multibody formulations. These constraint equations have a linear-quadratic nature and are therefore simple to evaluate. The pedestrain physical characteristics are scaled parametrically from a biomechanical database with standard anthropometric data. In order to prevent the biomechanical model to achieve physical unacceptable positions, a circumduction cone of control is defined in each articulation. When a relative position between two segments is detected outside the control cone, a penalty resistance torque, representing reaction moments in that articulation, is applied to both segments. The contact between the pedestrian, bus and ground is modeled using a continuous force model. This model evaluates the nonlinear contact force as function of the pseudo-penetration between the two surfaces in contact, their physical characteristics including the materials of the bodies and relative impact velocity between them. The contact surfaces, for the ground, biomechanical model and bus are modeled using planes and second and higher order ellipsoids respectively. The methodology is finally applied to the impact of a pedestrian by a bus in order to illustrate its use. The initial position of the pedestrian, impact angle and bus forward velocity are defined according to data collected on the field. The pedestrian kinematics, the potential for injury and the relative motion between the bus and pedestrain after the impact are evaluated as examples of the results available. (A)

  • Availability:
  • Corporate Authors:

    Woodhead Publishing, Limited

    Abington Hall, Abington
    Cambridge,   United Kingdom  CB1 6AH
  • Authors:
    • SILVA, MPT
    • AMBROSIO, JAC
  • Publication Date: 1999

Language

  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00795001
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, ATRI
  • Created Date: Jul 7 2000 12:00AM