A thin-walled rocket nozzle extension with a reinforcing ring is first processed at a higher temperature and assumed to be stress-free during processing. The extension is then allowed to cool down to the ambient temperature.

The extension materials exhibit different in-plane and through-the-thickness thermal expansion properties; therefore, the cooling process may induce significant residual stresses, particularly in parts with large curvatures.

A linear static analysis is performed to study the residual stresses on the nozzle extension under this uniform thermal (cooling) load. Special attention is given to the reinforcing ring at the jet exhaust where the highest stresses are expected.