Simulation of vehicle impact on steel and composite highway guardrail structures

Numerical simulations of vehicle impact on highway guardrails composed of steel and of a composite material are performed. The emphasis is on development of the modeling procedure, particularly that required for the composite material, for which a continuum damage model has been developed. Damage evolution equations are postulated as a function of current state of stress and damage, which results in implicitly rate-dependent behavior. The computations performed are used to examine the distribution and evolution of plastic strain for the steel sections and damage in the composite sections. These results are then be used to judge the integrity of the rail section. Velocity histories of the vehicle are used to evaluate the ability of the rail to absorb energy. Based on the simulations, the composite rail section performs better than a steel section of equal weight. The results also indicate that the composite constitutive model performs well in crashworthiness simulations.