Fig. 4.

An example of the simulation of the 30 cm long needle entering tissue vertically downwards from the top (with 12.7 mm long grooves) when the insertion depth is at 35 mm of the 70 mm insertion depth. The contours depicted are of strain, indicating that the fibers interacting with the right side of the needle (the side with the grooves) are under tension while the fibers on the left side of the needle body are under compression. The needle successfully eliminates the cohesive element and separates the two tissue bodies.