Citation

Xiaoyun Z, Xinyi H, Dongming Z, Xiaobo Y. Int. J. Crashworthiness 2020; 25(4): 351-359.

Copyright

(Copyright © 2020, Informa - Taylor and Francis Group)

DOI

10.1080/13588265.2019.1593289

PMID

unavailable

Abstract

In numerical simulation of vehicle-pedestrian accidents, pedestrian rest positions are greatly influenced by the friction coefficient between pedestrian and ground. Current researches on vehicle-pedestrian accident reconstruction often regard pedestrian-ground friction coefficient as a constant value. However, clothing fabric belongs to viscoelastic material. Some researches show that friction coefficient of viscoelastic material can be influenced by normal contact force. In this paper, a contact model between clothing fabric and asphalt road is built by computer simulations. The calculation based on this contact model indicates that the pedestrian-ground friction coefficient in accidents is not constant. Relationship between friction force and contact pressure is non-linear. Meanwhile, according to the simulation results of a real-world vehicle-pedestrian accident, influence of vehicle- pedestrian contact stiffness on pedestrian projection has been discussed, and simulation errors under different pedestrian-ground friction coefficients are calculated. Simulation results show that compared with traditional pedestrian-ground contact model, the non-linear pedestrian-ground contact model can obtain smaller simulation error with higher stability, which has validated the rationality of this contact model. AbbreviationsτfShear stress at surface contact pointsAReal contact areaaRMS roughness of the surfaceκConstant related to the average height of the surfaceβxCorrelation length of the surface in X-directionβyCorrelation length of the surface in Y-directionZ1Height matrix of surface 1Z2Height matrix of surface 2z¯1Average height of peaks on surface 1z¯2Average height of peaks on surface 2h0Distance between two rough surfacesξCharacterised distance between rough surfacesΔZDistance matrix between rough surfacesεRatio of real contact area to nominal contact areaReqGaussian contact radiusAijReal contact area of a single rough peakΔLAccuracy of contact area calculationTContact matrix between rough surfacesFijLocal contact force of a single rough peakE1Elastic modulus of surface 1E2Elastic modulus of surface 2υ1Poisson ratio of surface 1υ2Poisson ratio of surface 2fFriction forceμFriction coefficientμ′Feature friction coefficientE'Constant related to material property parameters

Language: en

Keywords

accident reconstruction; computer simulation; contact stiffness; Pedestrian–ground friction; rough surface contact