A finite element model of the lower limb for simulating pedestrian impacts.

A finite element (FE) model of the lower limb was developed to improve the understanding of injury mechanisms of thigh, knee, and leg during car to pedestrian impacts and to aid in the design of injury countermeasures for vehicle front-ends. The geometry of the model was reconstructed from CT scans of the Visible Human Project Database and commercial anatomical databases. The geometry and mass were scaled to those of a 50(th) percentile male and the entire lower limb was positioned in a standing position according to the published anthropometric references. A "structural approach" was utilized to generate the FE mesh using mostly hexahedral and quadrilateral elements to enhance the computational efficiency of the model. The material properties were selected based on a synthesis on current knowledge of the constitutive models for each tissue. Since no reliable data could be found in the literature for flesh, skin, and ligaments, new constitutive properties were determined from experiments on post-mortem human surrogate (PMHS) specimens. Optimization techniques were used to insure consistency among all material test and component test conditions. The validation process of the model included component level tests specific to pedestrian impact loadings from both the literature and more than 30 new PMHS tests. Overall results obtained in the validation indicated improved biofidelity relative to previously published FE models.