Wood-steel structure for vehicle restraint systems

Certain roadside safety barriers are structures mad e of steel and wood. This kind of structure is currently in fashion in location where the safety e quipments need to be discreet (mountains, countryside). In Europe, to be installed on the roadside, the veh icl restraint systems have to pass two crash tests , a defined in the European standard EN1317. Our aim is to develop a dynamic model of the multi material structure in order to understand and optimize the safety barriers i.e. to define the bes t association of the mechanical properties of both materials. The first part of this paper concerns three point b ending experimental tests at different energy level s. These laboratory tests were used as a basis for the evaluation of a material constitutive law. Then, a numerical parametric study which takes into account the variation of moisture content and temperature, as observed in the experiment, will be exposed. After that, a model of a roadside safety barrier an d procedure based on variation of failure modes analysis will be presented in order to correlate th e numerical model to the real crash test results. Finally, a parametric study, concerning wood mechan ical properties, will be performed in order to check the effect of this variation on the device pe rformances.