Meeting Abstract
Modeling the skin and blubber of marine mammals will aid in understanding injury from anthropogenic structures, such as the moving blades of an energy-generating tidal turbine. A material constitutive model model, detailing the mathematics of how a tissue behaves to various loads and forces can be created by using laboratory material tests as input. Previously we used uniaxial tensile testing of seal, orca, and porpoise soft tissue. Cetacean skin showed a stiffness of about 7 MPa and strength of about 2.5 MPa. We now expand to more types of tissue testing, including examination of the shear modulus and bulk modulus. After separating the blubber and skin soft tissues, subsections of each tissue were loaded in a test rig, recording torque and displacement for the duration of an rotational test for shear modulus. Bulk modulus was calculated using a volumetric compression test. These values, in conjunction with previous elastic modulus testing, allow us to explore the nonlinearity of the material and understand the appropriate level of complexity in modeling. Using multiple marine mammals, including seals and toothed whales, we can further understand how similar the skin of these animals is. In harbor porpoise testing, blubber bulk and shear modulus testing indicates that blubber is near to matching isotropic assumptions, while skin does not. In addition to modeling of injury mechanisms, contrasting between these species will allow further understanding of hydrodynamic or kinematic performance adaptations in marine mammals.
