System and method for minimizing occupant injury during vehicle crash events (9539969/12/991,501)
Inventors: Jeff Crandall, Costin Untaroiu, Eric Maslen, Dipan Bose. Issued January 10, 2017 in United States
A method, computer program product and apparatus for minimizing occupant injury by optimizing occupant restraint properties and/or actions in real time, during pre-crash and crash phases. The restraint system uses three catalogs and a database linking these catalogs. The catalogs include a catalog of possible occupant states, a catalog of possible collision scenarios, and a catalog of potential restraint control laws.
Mechanical characterization and Finite Element Implementation of the Soft Materials used in a Novel Anthropometric Test
Published by (Journal of the Mechanical Behavior of Biomedical Materials/Elsevier)
Authors: Wade Baker, Costin Untaroiu, Dawn Crawford, Mostafiz Chowdhury. Published October 01, 2017
Soft materials (e.g. polymers) are widely used in biomechanical devices to represent the nonlinear viscoelastic properties inherent in biological soft tissues. Knowledge of their mechanical properties is used to inform design choices and develop accurate finite element (FE) models of human surrogates. The goal of this study was to characterize the behavior of eight polymeric materials used in the design of a novel anthropomorphic test device (ATD) and implement these materials in an FE model of the ATD.
Tensile and compressive tests at strain rates ranging from 0.01 s−1 to 1000 s−1 were conducted on specimens from each material. Stress-strain relationships at discrete strain rates were used to define strain rate-dependent hyper-elastic material models in a commercial finite element solver. Then, the material models were implemented into an FE model of the ATD. The performance of the material models in the FE model was evaluated by simulating experiments that were conducted on the ATD lower limb.
The material characterization tests revealed viscoelastic strain rate-dependent properties in the flesh and compliant elements of the ATD. Higher modulus polymers exhibited rate-dependent, strain-hardening properties. A strong agreement was seen between the material model simulations and corresponding experiments. In component simulations, the materials performed well and the model reasonably predicted the forces observed in experiments
A finite element model of a six-year-old child for simulating pedestrian accidents
Published by (Accident Analysis and Prevention/Elsevier)
Authors: Yunzhu Meng, Wansoo Pak, Berkan Guleyupoglu, Bharath Koya, F. Scott Gayzik, Costin D. Untaroiu. Published January 01, 2017
Child pedestrian protection deserves more attention in vehicle safety design since they are the most vulnerable road users who face the highest mortality rate. Pediatric Finite Element (FE) models could be used to simulate and understand the pedestrian injury mechanisms during crashes in order to mitigate them. Thus, the objective of the study was to develop a computationally efficient (simplified) six-year-old (6YO-PS) pedestrian FE model and validate it based on the latest published pediatric data. The 6YO-PS FE model was developed by morphing the existing GHBMC adult pedestrian model. Retrospective scan data were used to locally adjust the geometry as needed for accuracy. Component test simulations focused only the lower extremities and pelvis, which are the first body regions impacted during pedestrian accidents. Three-point bending test simulations were performed on the femur and tibia with adult material properties and then updated using child material properties. Pelvis impact and knee bending tests were also simulated. Finally, a series of pediatric Car-to-Pedestrian Collision (CPC) were simulated with pre-impact velocities ranging from 20 km/h up to 60 km/h. The bone models assigned pediatric material properties showed lower stiffness and a good match in terms of fracture force to the test data (less than 6% error). The pelvis impact force predicted by the child model showed a similar trend with test data. The whole pedestrian model was stable during CPC simulations and predicted common pedestrian injuries. Overall, the 6YO-PS FE model developed in this study showed good biofidelity at component level (lower extremity and pelvis) and stability in CPC simulations. While more validations would improve it, the current model could be used to investigate the lower limb injury mechanisms and in the prediction of the impact parameters as specified in regulatory testing protocols.
| Human Dynamics and Rehabilitation
| Risk Analysis and Assessment