Cold spray restoration technique improves aircraft safety.

Corrosion is a constant threat to the safety of Australia’s transport infrastructure, particularly the aviation industry. A new repair technique being developed by Professor Rhys Jones does more than simply patch up the problem; it restores the structural integrity of the metals involved. His research could improve the safety and life span of aircraft globally. It is being tested by the Australian Defence Force and has drawn the attention of international aviation giants Boeing and Airbus.

The Australian Government raised questions about the safety of ageing aviation infrastructure in its 2009 Aviation White Paper. Aviation regulator the Civil Aviation Safety Authority shares these safety concerns.

Rhys’s research is expected to reduce the danger posed by ageing and corroded aircraft.

When exposed to extreme weather and environmental conditions metal develops small defects that grow larger and corrode over time.

‘Metal is like a human body – as it gets older it gets damaged. Just as our DNA does not renew itself properly, the problem of corrosion gets worse over time,’ Rhys says.

His research to address the corrosion issue is an extension of a technique, commonly called ‘cold spray’, that was first developed in Russia in the 1990s to ‘regrow’ aluminium.

In partnership with the Melbourne-based company Rosebank Engineering, Rhys and his research team have extended the cold spray technique to develop a new repair process that can actually improve the structural integrity of commercial and military aircraft.

They create a high-strength, durable material to repair corrosion by firing aluminium particles at supersonic speed at the base structure. The particles embed in the metal and build up a deposit of aluminium alloy on the corroded area.

In this way aluminium can be effectively ‘regrown’ so it has the same strength and durability as the more robust parts of the aircraft.

The Australian Defence Force is already using this technique to repair some Australian Navy helicopters. This is part of a testing process, in conjunction with the Naval Aircraft System Project Office and the Royal Australian Air Force Directorate General Technical Airworthiness, which could see the technique adopted for use across the entire navy and air force fleets.

‘Australia has a long history of developing solutions to address problems associated with ageing aircraft, and in many cases these solutions have been adopted worldwide,’ Rhys says.

Funding for his work comes from an Australian Research Council (ARC) grant, Rosebank Engineering, the Defence Science and Technology Organisation (DSTO), the Royal Australian Air Force Directorate General Technical Airworthiness and the Australian Defence Materials Technology Centre.

Aviation is a continuing passion for Rhys, one he combines with a strong interest in defence science. However, his expertise in structural mechanics has drawn him to research in other fields.

He is involved in several rail-related projects with partners including Queensland Rail and AMSTED Rail International, the world’s largest rail component manufacturer. One project is investigating ways to make rolling stock more durable, minimising breakdowns and improving freight productivity. The Cooperative Research Centre for Infrastructure and Engineering Asset Management is funding this work. The Cooperative Research Centre for Railway Innovation is also funding research to strengthen the wheels of rolling stock and extend their life.

Rhys used his talent for analysing mechanical and structural integrity to help the 2009 Victorian Bushfires Royal Commission’s investigations and also led the Longford Royal Commission’s investigation into the mechanical causes of the Esso Longford gas plant explosion in 1998.