Biomimetic intruder tip design for horizontal penetration into a granular pile

In nature, woodpeckers peck trees with no reported brain injury. A highly functional system comprising a hyoid bone, smooth skull, straight pointed beak with varying lengths of upper and lower beak bones, and rhamphotheca is one of the adaptations that enable efficient pecking. Soil penetration is an energy-intensive procedure used in civil infrastructure applications and is often followed by pushing, impact driving, and digging. This study uses discrete element modeling to evaluate the effect of woodpecker beak mimetic intruder tip design with wedge offsets on lift and drag forces during horizontal penetration into granular piles. The findings show that the wedge offsets of the intruder have a negligible effect on drag forces. By contrast, lift forces can be manipulated by adjusting the top and bottom offsets of the intruder, which can be used to guide the intruder upward, downwards, or horizontally. Furthermore, as the width of the intruder increased, the lift and drag forces also increased.