TS2LBMCResearch teams Impact of structures Display the main menu

Impact of structures

Research thematic

A vehicle that crash on a bridge, a motorcycle protected by a road safety barrier when an accident occurs, a pedestrian impact on a vehicle, a hailstone falling down on a tile or a car body, a bird striking a windscreen (plane, car), … have one thing in common : a deformable projectile impacting a deformable target. The main problem is to predict the damage occurred on both projectile and target, in accordance with the parameters characterizing this impact: choc relative speed, contact law between structures, … These facts are difficult to take into account in structure calculation, according to their occasional aspect and the evaluation difficulty of the force interaction between structures.

According to this context, this team works on the following topics:

    • Simplified model of impacted structures
    • Force rebuilding using indirect measurements
    • Impact/crash tests energy absorption
    • Dynamic behavior of materials
    • Uncertain and robust models

     

    Skills


    We are interested in problems involving large displacements, large elastic and plastic deformations, and then nonlinear behavior law. worked on steel-wood roadside safety (Clement Goubel PhD 2012) and more recently on roadside safety including motorcyclist protection (current PhD) . We worked on an experimental study of energy absorption of vehicle structure elements (Jerome Bouchet PdH 2000): a specific bench test was designed and built (measurement analysis on a Hopkinson bar type system) that enable us to conduct better analysis of the different structure elements that we were studying concerning energy absorption (composite –aluminum multi material tubes)


    The team has also abilities on one hand for experimental bench design and building, data recording, ….. (turbo reactor dynamic bench, partnership SNECMA and Ecole Centrale of Lyon),  and on the other hand for numeric model: buckling behavior of Ariane V’s cryogenic reservoir (Partnership INSA of Lyon - Cryospace), hailstone impact on tiles (partnership UCBL – Lafarge), development of non-linear behavior laws on shell elements. We designed and built a Hopkinson bars experimental bench for high speed materials characterization. The dynamic behavior laws extracted from these experiments will be used in our structure numerical models.


    Finally, the team is interested in uncertain and robust model problem in dynamics. This supposes to take into account model uncertainties and, loading and boundaries uncertainties. For this purpose, we develop methods based on polynomial chaos to evaluate, with reasonable calculation cost, the influence of input parameter variabilities on the output data.

     

    Methodology - Approach

    Our team chosen approach is most often to work on experimental, analytical and numerical aspects of a problem simultaneously. Experimental works give us database to lead analytical models and validate numerical models.