Material fatigue is a big topic in aircraft construction. The aluminum parts of an aircraft are exposed to constantly changing loads and will show fatigue in the long term. Laser shock peening is a technology for surface treatment of metals, which is now being researched for the first time for aircraft construction.
The challenge: Targeted surface treatment without environmental impact
Traditionally, aluminum aircraft parts are exposed to shot peening to provide greater strength and fatigue resistance. But shot peening is not particularly eco-friendly and also does not allow for truly precise application.
Laser Shock Peening is a well-known technology that enables precise surface treatment and requires only light and water. It was previously only used in the US military sector, but also offers decisive advantages in the field of civil aviation.
The solution: A flexible technology that saves weight and costs
The principle is actually quite simple: If a metal is bombarded with a pulsed laser beam through a thin layer of water, a high-pressure plasma is created on the surface with each pulse, which expands explosively. The inertia of the water prevents an expansion of the energy to the rear, so that it is fully concentrated on the metal. The result is an irreversible deformation of the metal and a targeted local hardening of its surface structure.
Laser Shock Peening is ideal for improving the fatigue properties of the metal. The formation of cracks induced by the natural fatigue is thus effectively counteracted. Also, certain structural components can be more filigree and thus easier to design without affecting their strength.
Laser Shock Peening also offers new possibilities for the large-scale deformation of sheet metal. The advantage here is that the technology is extremely flexible and can be used for a wide variety of dimensions and geometries. This could replace today’s heavy presses that need to be re-set for each sheet metal part.
Especially in the aviation industry, Laser Shock Peening offers decisive advantages. The technology can not only be optimally integrated into increasingly digitized work processes. It also offers maximum flexibility and fits perfectly with the rather small quantities that are involved in aircraft construction.
The potential: new applications for a sustainable process
In the TechCenter of the Hamburg Center for Applied Aerospace Research (ZAL), the first laser shock peening system in Europe was put into operation in October 2018.
This technical infrastructure will serve to develop different applications of this technology for the aviation industry. At the heart of the development work are solutions for fatigue improvement of highly stressed aircraft components. Further research focuses on novel applications for the deformation of sheet metal parts, which are considerably more flexible and economical than previous methods.
The ZAL is a company of the city of Hamburg together with Airbus, Lufthansa Technik, the ZAL Förderverein, the German Aerospace Center, as well as colleges and universities of the city of Hamburg.