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Previous full-scale pedestrian impact experiments using post-mortem human surrogates (PMHS) and sled-mounted vehicle bucks have shown that vehicle shape relative to pedestrian anthropometry may influence pedestrian kinematics and injury mechanisms. While a parametric study examining these factors could elucidate the complex relationships that govern pedestrian kinematics, it would be impractical with PMHS tests due to the relative expense involved in performing numerous experiments on subjects with varying anthropometry. Finite element (FE) modeling represents a more feasible approach since numerous experiments can be conducted with a fraction of the expense. However, there have been no studies to date depicting kinematic validation of a human pedestrian FE model in full-scale collisions using different vehicle and pedestrian geometries. Therefore, this study used an FE model of the Polar-II pedestrian dummy that was previously validated against full-scale test data.

Material and structural properties of human tissues under impact loading are needed for the development of physical and computational models used in pedestrian and vehicle occupant protection. Obtaining these global properties directly from the data of biomechanical tests is a challenging task due to nonlinearities of tissue-test setup systems. The objective of this study was to develop subject-specific finite element (FE) techniques for material identification of human tissues using Successive Response Surface Methodology. As example, the test data of a human femur in three-point bending is used to identify parameters of cortical bone. Good global and local predictions of the optimized FE model demonstrate the utility and effectiveness of this new material identification approach.

The goal of this study was to develop and validate a finite element (FE) model of the Polar-II pedestrian dummy. An upper body model consisting of the head, neck, shoulder, thorax, and abdomen was coupled with a previously validated model of the lower limb The viscoelastic material properties of the dummy components were determined from dynamic compression tests of shoulder urethane, shoulder rubber and abdominal foam. For validation of the entire upper body, the model was compared with NHTSA response requirements for their advanced frontal dummy (Thor) including head and neck pendulum tests as well as ribcage and abdominal impact tests. In addition, the Polar-II full body FE model was subjected to simulated vehicle-pedestrian impacts that recreated published experiments. Simulated head and pelvis accelerations as well as upper body trajectories reasonably reproduced the experiment.

The structural properties of the four major human knee ligaments were investigated at different loading rates. Bone-ligament-bone specimens of the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments, obtained from post-mortem human donors, were tested in knee distraction loading in displacement control. All ligaments were tested in the anatomical position corresponding to a fully extended knee. The rate dependence of the structural response of the knee ligaments was investigated by applying loading-unloading cycles at a range of distraction rates. Ramps to failure were applied at knee distraction rates of 0.016 mm/s, 1.6 mm/s, or 1,600 mm/s. Averages and corridors were constructed for the force response and the failure point of the different ligaments and loading rates. The structural response of the knee ligaments was found to depend on the deformation rate, being both stiffer and more linear at high loading rates.