Abstract:
Engineering a product for optimal reliability at minimal life cycle costs (LCC) has been a challenging
aspect to nearly all industries. Uncertainties complicate control over these costs, with many LCC
models having been developed to determine the optimal design.
This project aims to find the best reliability level for a low-cost paediatric prosthetic knee (PPK)
under development by the Council for Scientific and Industrial Research (CSIR) and minimise its LCC.
An agent based simulation in combination with system dynamics techniques is utilised to reach this
goal. A pilot version of the agent based model is compared with an analytical Monte Carlo simulation
in order to validate the use of the agent based simulation. The LCC are especially important, as the
CSIR do not intend to make a profit from the PPK and all costs will be attributed to research and
development. A mathematical expression capable of predicting the time to failure based on user
patterns is developed, which will assist prosthetists and parents with future financial planning for
the eventuality of a failure.
What is to be learnt from this project is the important link and interaction between reliability and
product performance, culminating in its LCC. The end-beneficiaries are essentially the children who
will receive a well-designed product to use and improve their lives. Future low-cost prosthetic
products may also be able to use this combined modelling approach and minimise their expenses.
