Figure 113. Stable behavior is achieved by reducing the time step to that needed for stable contact surface behavior (default Grade 1 saturated pine properties without rate effect). Diagrams.

0.0 milliseconds.

This figure shows a computer-generated illustration of a post, embedded in a concrete brace using the single neoprene flap. The majority of the post is colored red, with a small section near the top colored blue, representing the impact point and a small section at mid-point on the post representing the breaking area. This latter area is also the area in which the post is embedded into the concrete base. This first figure shows the impact vehicle making contact with the post, though no damage has as of yet occurred.

15 milliseconds.

This figure shows the top half of the post leaning to the right hand side as a gap forms in the green section of the post from the resulting impact. The top half leans at a rough twenty-five degree angle from its original position.

50 milliseconds.

This figure shows the top half of the post leaning considerably more, the gap near the midsection widening as the post now leans at a rough forty-five degree angle.

100 milliseconds.

This figure shows the top half of the post laying nearly parallel with the ground, the gap fully open, the top half of the post being held onto the bottom by only a fraction of the remaining post.

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FHWA-HRT-05-096