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Originally known for pioneering innovations in packaging, and later, rapid integrated growth in petrochemicals, today Huntsman Advanced Materials has 11,300 employees, 57 operations in 22 countries and revenues over $10 billion. The world’s most significant and essential industries rely on Huntsman businesses to manufacture basic products for a variety of end-use applications. This is especially true in the aviation industry, where the company created a composite solution that is being applied to more and more fan blades on large engines for civil airplanes.
(Published on April 2006 – JEC Magazine #24)
Today’s engines on commercial jets have hollow compressor fan blades. Prior to Huntsman’s innovation, which was achieved through a partnership with the University of Sheffield and Rolls Royce, honeycomb or line-core materials were used to fill the void and maintain the cross-sectional profile as the fan blades flex.
With the help of researchers at the University of Sheffield, Huntsman was able to fill the fan blade void with Araldite®1641, a liquid composite solution using a reactive two-component epoxy syntactic made from epoxy and amine materials.
“An aerospace research and development team from Huntsman Advanced Materials has developed epoxy-based syntactic fillers (low-density polymer fillers with damping properties) that are being applied to some Rolls-Royce civil aero engines to absorb vibrational energy over a wide operational temperature range.
Working with Rolls-Royce engineers and the Universities of Nottingham and Sheffield, Huntsman created a lightweight adhesive solution for injection into the hollow fan vanes of engines. Each of an engine’s 50 outlet guide vanes – which provide optimum direction of air after it has passed through the fan – contains the Araldite® 1641 material.
While the technology has been applied to the fan vanes of some engines in service, further research is now under way to see if it can be applied to other aero-engine components to provide even more vibration damping for improved durability and life.”
Making the solution
Making this solution work for the fan blade was no small task. Rolls Royce wanted a solution that would have an acceptably low level of dampening, something Huntsman’s Dr Philippe Christou said was one of the biggest challenges. The metallic qualities of the fan blades cause low dampening levels, which can result in excessive vibration.
However, the composite used increased the structural dampening of the blades, which absorbs and thereby reduces vibrational energy over a large temperature range. In addition, the syntactic composite’s liquid state before it is cured made processing easier and less expensive.
According to Dr Christou, “The goal was to reduce weight and improve dampening performances when compared to the standard metallic solution. Syntactics were known to be good candidates for this kind of application, but none of the known existing syntactics was meeting the dampening requirements for this particular application.”
Sheffield University helps out
Sheffield University’s Department of Mechanical Engineering played a key role in helping Huntsman find the right solution for Rolls Royce. The department was responsible for developing an appropriate test for the dampening evaluations.
Led by Dr Jem Rongong, the University numerically analysed the engine parts to find the ideal material properties. They also developed numerical models of the material microstructure to predict behaviour; from there, they were able to specify mix ratios for the syntactics. This work helped Huntsman produce the finished materials for the fan blades, which are now seen in many Rolls Royce engines.
Dr Rongong described the experience of working with Huntsman and Rolls Royce as a good, constructive collaboration and “a good use of complimentary skills. I wish all collaborative activities were so beneficial!”.