The objective of this study is to develop a mathematical model which can predict load propagation and kinematics of the foot and leg in frontal automotive impacts. A multi-body model developed at the University of Virginia (United States), and validated for blunt impact to the whole foot has been used as basis for the current work. This model includes representations of the tibia, fibula, talus, hindfoot, midfoot and forefoot bones. Additionally, the model provides a means for tensioning the Achilles tendon. The simulations conducted correspond to tests performed by the Transport Research Laboratory (TRL; United Kingdom) and the University of Nottingham (UK) on knee amputated cadaver specimens. In order to improve the model response to the local and blunt impact test data, a more biofidelic shape of the hind and midfoot, a distal-to-proximal translation capability at the ankle joint, and modified contact properties were included in the model. Other model parameters that were found to significantly influence the load propagation are the ankle and subtalar joint location, the configuration of the midtarsal joint and the knee joint properties. In addition, the impact location, foot initial state and level of Achilles tension influenced the model response. The conclusions are that the model now is valid in local impacts to the foot, and still maintains validity in blunt impacts to the foot.
Abstract