Recent investigations considering flexible, steerable
needles for minimally invasive surgery have shown the
significance of needle shape in determining the needle-tissue
interactions leading to the access of targets. Digital Image
Correlation has enabled internal deformation and strain caused
by needle insertions to be seen in a soft tissue phantom at high
resolution for the first time. Here, the impact of tip design
on strains and displacements of material around the insertion
axis is presented using Digital Image Correlation in a stable,
plane-strain configuration. Insight into the shape of needles to
minimise tissue trauma and generate interactions that would
enable optimal steering conditions is provided. Needle tips
with an included bevel angle up to 40◦
result in asymmetric
displacement of the surrounding tissue phantom. Increasing
the included tip angle to 60◦
results in more predictable
displacement and strains that may enhance steering forces with
little negative impact on the phantom.