Stereoscopic digital image correlation (DIC) is used to measure the shape evolution of a soft, transparent thermoplastic material subject to a high strain rate compression test performed using a Kolsky bar. Rather than using the usual Kolsky bar wave analysis methods to determine the specimen response, however, the response is instead determined by an inverse method. The test modeled using finite elements, and the gel stiffness giving the best match with the shape and force history data is identified by performing iterative simulations. The advantage of this approach is that specimen equilibrium is not required, and friction effects, which are difficult to eliminate experimentally, can be accounted for. The thermoplastic is modeled as a hyperelastic material, and the identified dynamic compressive (non-linear) stiffness is compared its quasi-static compressive (non-linear) stiffness to determine its rate sensitivity.
Proceedings Title: Proceedings of the SEM 2011 Annual Meeting
Conference Dates: June 13-16, 2011
Conference Location: Uncasville, CT
Conference Title: SEM 2011 Annual Meeting
Pub Type: Conferences
blast protection, Kolsky bar, digital image correlation, tissue simulant material, inverse method