Design verification and optimisation is commonly employed during the conceptual phases of the design process to ensure that the mechanical design meets the engineering requirements in the most cost effective manner. The use of advanced engineering analysis methods at this early stage in the design process can significantly reduce the time to full production by reducing the number of prototype testing cycles or can be used in its own right to demonstrate adequacy without the need for prototype testing.

Case Study: FCL have recently completed work to rectify a fault in the design of a quartz glass roller used in an infra-red polymer bonding process. The roller consisted of a glass tube with steel supporting rings bonded to each end by a layer of silicone rubber. Six drive wheels, bearing on the steel supporting rings, actuate the roller such that a downward load is applied through the lower four drive wheels. The analysis of brittle materials such as glass shows that, in the absence of inherent flaws, fracture will occur at the elastic limit of the material or at a very small strain beyond this point. Experiment has shown that the maximum principal stress theory is the most satisfactory for predicting failure in such materials.

FCL’s initial work concentrated on an analysis of the faulty roller design with a view to establishing the validity of this theory of failure by comparison of predicted and observed failure planes. With a satisfactory correlation thus established, FCL were able to quickly and confidently assess a variety of minor modifications to the roller design before finally arriving at a satisfactory solution. The success of the work has been proved by the longevity of the new roller which has already surpassed the most optimistic life expectations.