The significance of rate dependency in blade insertions into a gelatin soft tissue phantom

An improved understanding of the detailed tool–tissue interactions in soft tissue phantoms is necessary to optimise the design and actuation of novel surgical devices. Incorporating rate dependency of these interactions provides general, rather than specific, working conditions. Blade insertion experiments and accompanying finite element simulations examine contact interactions, strain energy release rate and deformation in a gelatin phantom with a modulus of approximately 10 kPa. Insertion rates of 0.25–2 mm/s show frictional response and strain energy release rate more than doubling. This demonstrates the importance of testing phantoms over the full range of operating conditions. The role of the coefficient of friction between the tool and the tissue and the related frictional energy expenditure are also studied and discussed.