Development of an Impact Absorber for Roadside Barriers

The work presented in this paper was developed with the objective of increasing road safety for motorcycle drivers. Guardrails are traffic barriers placed along the roadsides to protect vehicles from hazards behind the barriers. These guardrails are constructed using standard steel W-beam mounted on spaced posts. When accidents involving motorcycles occur, the barrier posts are extremely dangerous causing severe injuries on motorcycle passengers. In order to reduce these injuries, an energy-absorbing system was developed. This protective device will be placed on the guardrail post and would minimize the injuries and reduce the impact accelerations. This impact attenuator was designed respecting the European standards EN1317. In this research, numerical simulation software was used (LS-Dyna) to determine the effects of the proposed impact attenuator system on motorcyclists regarding dynamics and injury criteria. The impact attenuator model was based on an elastic-plastic material capable of absorbing the high kinetic energy of the dummy. The geometry of the energy-absorber was designed obeying the requirements of an extruding manufacturing process. The section profile of the proposed 3D geometry model has various layerss intelligently oriented so that the deformation process may present a buckling behaviour. With this research, a low cost impact attenuator device was developed in order to protect motorcyclists against post barriers crashes. The new protector device guaranties a HIC lower than 1000, as required for EN1317 European Standard accident conditions.