A research team at Worcester Polytechnic Institute (WPI) in Worcester, Massachusetts, USA, has been granted funding to research how stress and fatigue cause microscopic damage to form in metal components, so that it can extend the life of military and commercial aircraft.
The WPI team will develop new tools and technology to detect the formation of cracks in aircraft components and monitor their progression – and even to predict when a crack will be serious enough for the aircraft to require servicing. WPI says the outcome of the research has the potential to keep military aircraft in service longer while also improving safety and on-time performance for commercial airlines.
The US Army Research Office is funding the work, which allows WPI to acquire a sophisticated, nondestructive evaluation system to study the microstructure and behavior of metals through the use of eddy-current sensor arrays and other advanced tools.
The WPI aims to understand and monitor how tiny cracks are initiated and then grow in metal components as they are subjected to repetitive (or cyclic) strains and stresses similar to those that wings, fuselages and other aircraft components experience in service. Using a new imaging system, the researchers are able to view the initiation and propagation of cracks at the nanometer scale while metal samples are stressed in a servo-hydraulic testing machine. These fatigue cracks can be detected both at the surface of metal samples and also by using electromagnetic induction within the metal microstructure.
With the knowledge gained through laboratory testing, advanced characterization and computational modeling, the team is looking to develop new lightweight metal alloys that are more resistant to cracking or in which small cracks are less likely to expand into larger fissures that would require a component to be repaired or replaced.
In addition, the WPI team hopes to be able to develop algorithms that will make it possible to predict, based on the state of stress and the rate of crack progression in a component, when servicing will be required.
November 27, 2015
