Boundary conditions for the virtual testing of athletic footwear

The design development process of athletic footwear is a long and iterative process. Currently the shoe goes through a design, prototype and mass production phase before the shoe reaches the consumer. The basis of iteration is the performance of the shoe in the laboratory and wear tests, which are mainly carried out in the prototype phase. To improve the performance of the shoe in these tests either better tests are needed to allow a better understanding of how the shoe performs or the shoes should be modelled and laboratory tests simulated prior to prototype to eliminate the need for early iteration. This thesis investigates the possibility and practical applicability of simulating test conditions using the finite element method in order to predict the performance of modelled shoes. The investigation is split into three objectives, the replication of existing laboratory mechanical tests into virtual tests; the development of a technique to develop more realistic and complex footwear tests and the integration of the technique into a virtual test. A process was created which identified how the finite element method was applied into a virtua1 footwear test highlighting how the method will be validated. This process was used to confirm it is possible to replicate the loading scenarios of simple, repeatable laboratory mechanical tests with confidence. Realism and complexity of footwear tests can be improved either by modifying existing tests or creating a method that develops new loading scenarios. A prosthetic foot was modelled with success as a method to improve the realism of existing mechanical tests and increase complexity of future tests. Kinematic and kinetic data taken from the stance phase of the gait cycle formed a method that can generate boundary conditions for new virtua1 footwear tests. The positional measurement method to generate boundary condition was integrated into virtua1 tests using a transformation mathematical technique. The kinematic data is used to drive the virtua1 test and the kinetic data is used to compare the results with reality. Initial results found virtual and reality were visually similar and small differences in the quantifiable parameters could be accounted for. Modifications to improve efficiency in the solving of the virtual test and therefore increase the usability of this method in the design development process were investigated. This was successful and showed it was possible to predict the performance of the shoe in a realistic and complex test loading situation.