Abstract
A uniquely configured vehicle suspension system, manufactured primarily of lightweight composite
materials, is required for the University of Johannesburg’s Solar Powered race vehicle. For this design to
reach successful completion, an assessment framework is needed that would scrutinise and analyse every
phase of the development. Therefore, the focus is on the design and development of a prototype
composite vehicle suspension system and the framework implemented to control the research and
development process. The National Aeronautics and Space Administration (NASA), as well as Departments
of Defence and Energy in the United States of America, have established a technology assessment model
known as a “Technology Readiness Assessment” (TRA). The purpose of this assessment model is to
identify those elements and processes of technology development that are considered critical to ensuring
the intended operation of the system is reached, and ultimately that the project is a success. The
Technology Readiness Assessment (TRA) can be viewed as an expansion on the scientific method, with an
hypothesis tested and communicated results then taken further to be implemented on a demonstration
platform and final system [10]. The TRA assessment comprises of various technology readiness levels
(TRL), which are an indication of the progress level or maturity of a technology element, with the TRL
scale ranging from 1 (basic principles observed) through to 9 (the total system has been used successfully
in project operations). Beginning with the lowest level of technology readiness (TRL 1), the problem
background will be summarised, and design requirements as well as parameters formulated based on
both design goals and competitive platform safety regulations for a new vehicle suspension design. This is
followed by a literature review focusing on suspension, steering and braking design theory as well as
advanced composites. Once the relevant theory and summarised design requirements are in place, the
design concepts can be generated and finalised based on these requirements, which will allow for the
eventual complete computer aided design (CAD) model of the system to be created. This constitutes a TRL
2 level assessment, with the primary deliverable being a complete CAD model and the identification of
critical technology elements or “at risk” design elements that require further investigation and validation
prior to their respective inclusion in the final system. These “at risk” elements will then form the basis of
the experimental programme. For the various composite components required in the lightweight
suspension system, the TRL 3 assessment has been modified to incorporate the development of
manufacturing processes. In primarily making use of a resin infusion composite processing technique, an
accurate and repeatable procedure is needed for component development and in order to create samples
required for laboratory scale and relevant environmental testing. Laboratory scale testing (TRL 4)
comprises of three experiments based on known ISO and ASTM standards, while relevant environmental
(inservice
application) experiments (TRL 5) comprises of four designed static load tests for component
validation. Once the “at risk” components have been validated, they are integrated into the final
assembly, in preparation for static system evaluation (TRL 6). Low speed (TRL 7) and high speed (TRL 8)
testing of the vehicle as a systemcommissioning
phase. For final system operation, the suspension
assembly will be assessed when implemented into a solar powered vehicle, to compete in the 2014 Sasol Solar Challenge. This is an international crosscountry
competitive endurance event spanning the length
and breadth of South Africa (over 2000 km). Additionally the vehicle will be the main showpiece in the
2015 African Solar Drive. A 4000 km event spanning parts of South Africa, Namibia and Botswana. Finally,
the Technology Readiness Assessment framework will be analysed and reformulated as needed to better
suit future technology development requirements for a composite suspension system.