Finite-Element Modeling of G2 Guardrail

Abstract

A finite-element model of the AASHTO G2 guardrail (weak-post W-beam) was developed and analyzed under vehicle impact conditions by using LLNL-DYNA3D, a nonlinear, explicit, three-dimensional, public-domain, finite-element code. The modeling procedures and problems encountered are described, and suggestions for further research are given. W-beam and S3 × 5.7 steel post mesh optimization procedures and results are described. A suitable point of fixity for the posts to account for soil effects is determined. W-beam-to-post connections were investigated by three different methods. Impact influence lengths and problems associated with modeling flexible barriers are discussed. The steps taken to assemble a model, including a prebuilt vehicle model, are given. The G2 guardrail was struck with the 820C vehicle model, developed by FHWA, at a speed of 26.69 m/sec (59.7 mph) and an angle of 15.4 degrees.