Having characterised the properties of the Hytrel material, the inversion itself is modelled using finite element analysis. This enables the understanding of the effects of seemingly minor imperfections in the dome manufacturing process on the high-speed inversion, see below. We concluded that the inversion velocity was less sensitive to certain types of imperfections and more sensitive to others. The modelling process also enables the prediction of properties of domes with a different geometry.
A further area of investigation was the strengthening of the material itself through a biaxial orientation process, see below. The pre-stretch encourages a microstructure that is stronger in the plane of the dome, and as such allows for the use of thinner and lighter domes. A thin biaxially stretched dome accelerates to much larger velocities than the original dome, but cannot be made using traditional injection moulding. An experimental program investigated a stamping procedure to produce biaxially oriented domes. Inversion velocities of around 300m/s can be achieved with the new domes.
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