Performance limits of commonly used barriers in terms of acceptable vehicle impact heights were identified using non-linear finite element methodology. Finite element models for four widely used guardrail systems were developed. The selected guardrail/barrier systems are the modified G4(1S) W-beam guardrail, modified thrie-beam guardrail, Midwest guardrail system, and modified weak post W-beam guardrail. LS-DYNA simulations using these guardrail models were validated based on the results obtained from existing crash tests performed on flat terrain. To define vehicle containment limits, LS-DYNA simulations were performed with variable vehicle-to-barrier impact heights on guardrails placed on flat terrain. Override and underride limits for each guardrail model were identified using NCHRP Report 350 design vehicles. Vehicle impact height was parametrically varied to determine performance limits of each barrier as defined by initiation of override or rollover for the pickup truck and underride for the small passenger car. (Author/publisher)
Abstract