Meeting Abstract
Tidal energy has an immense potential for creating renewable energy and is being investigated worldwide. In the emerging field, potential environmental consequences of installing tidal turbines must be evaluated. Marine mammals often use tidal channels for feeding and traveling and may collide with the spinning blades. This study aims to quantify the soft tissue response of two marine mammal species, Southern Resident killer whale (Orcinus orca) and harbor porpoise (Phocoena phocoena), during a collision with a tidal turbine blade. Biomechanical properties of skin and blubber are needed to implement a finite element model determining the extent and severity of a turbine blade strike. Using stranded harbor porpoise and killer whale, we collected skin and blubber for post-mortem examination of their material properties. Tensile tests of the skin and blubber layers were performed on these specimens to determine tensile stiffness and tensile strength, as well as the strain rate effects on these quantities. Samples were taken in three orientations to investigate anisotropy. Both types of tissue exhibited a large plastic region, showing non-linear behavior. Compressive spherical indentation tests were performed with the composite skin and blubber layer and on the blubber layer alone to assess the difference between the tension and compression behavior. It was found that the compressive stiffness of blubber was approximately an order of magnitude lower than corresponding tensile data. These experiments were subsequently recreated using the commercial finite element solver ABAQUS to validate the numerical material constitutive models. Ultimately, the numerical models can be extrapolated to full-scale, realistic models of marine mammals to assess their susceptibility to injury from turbine blade impact or similar phenomena.
