A three-dimensional pedestrian knee joint model was developed as a first step in a new description of the whole pedestrian body for computer simulations. The model was made to achieve better correlation with the results from previous tests using biological material. The model of the knee joint includes the articular surfaces, ligaments and capsule represented by the ellipsoid and plane elements as well as the spring-damping elements, respectively. The mechanical properties of the knee joint were based on available biomechanical data. The model was verified using data taken from tests with biological material by carrying out simulations using the MADYMO 3D program. The following parameters were varied in the simulations: bumper height and bumper compliance. Four computer simulations were performed and the results thus obtained were compared with those from four test series with biological material. The impact force, the condyle interface forces, the ligament forces and the ligament relative elongations were all calculated and verified with the results of the tests with biological material. The output parameters calculated from the knee joint model correspond in general to what was observed in the studies with biological material. Two further computer simulations were performed to study the influence of the upper body mass to the distribution of the forces in the simulated knee structures. The results indicate that body mass has an influence on: a) the impact and condyle forces; b) the ligament strain; and c) the trajectory of the lower extremities.
Abstract