14th International Conference on Shot Peening

Laser Shock Peening, the Use of Lights for Structural Performance Enhancement of Metallic Airframes – Historical Background and Future Prospective

Biography:

Dr Domenico Furfari is Technical Advisor for Structural Analysis at the Airbus Airframe Competence Centre. His professional background is structural analysis in the field of fatigue and damage tolerance of metallic airframes. He obtained his Engineering degree from the University of Pisa, Italy, awarded with 110/110 from the Aerospace department in the field of Aeronautic Structures. After a short stay at the University of Pisa as a research assistant, he moved to Cranfield University, UK , where he obtained his PhD from the School of Industrial and Manufacturing Science with the thesis on “Fatigue Short Crack Behavior of Ti-10-2-3Alloy for Helicopter Structural Applications”. He joined Airbus Operations GmbH in Hamburg, Germany, in 2004 and worked in the repair department for fatigue and damage tolerance as Airbus Germany site coordinator for the EU project (FP6). Since 2006, he has coordinated and led various research and technology projects at Airbus. Most projects are carried out in cooperation with research institutes and universities worldwide working together in the field of structural analysis and novel technologies for composite and metallic materials. His main areas of interest range from new technologies for fatigue enhancement of metallic structures (e.g. Laser Shock Peening) to novel repair techniques for embodiment in typical aircraft commercial MRO (Maintenance Repair Overhaul) environment.

Abstract:

Surface technologies in aeronautical industry can ensure salvage in hot spots for fatigue and crack growth performance. Technologies improving the resistance of structures to in service degradation processes, such as fatigue, are of benefit to the aircraft industry to extend the service life and reducing maintenance costs. Residual stresses by Laser Shock Peening (LSP) applied into a metallic structure can improve the economical and ecological impact of an aging fleet as well as of future aircraft. An historical review of the LSP process from the first laboratory observation to the industrial applications will be provided; Research activities, from early ’60 to mid ’70, to understand the physics of laser pulse forming a plasma pressure on a surface. In 1974 at the Battelle Memorial Institute in Columbus, Ohio investigation of the effect of laser shock waves to improve the material strength of Al7075 started. A large pulsed laser for fusion studies was used in this case but not practical at all for industrial applications. 20 years development required to industrialize LSP in a production environment. In 1995 LSP Technologies Inc. started LSP for the production line at GE Aviation. How LSP can enhance fatigue and crack growth for different aerospace metallic materials: Al alloys (2024-T351, 7010-T7451, 7050-T7451), Stainless Steel X3CrNiMoAl13-8-2 will be presented. The depth of the compressive residual stresses is controlled by the LSP parameters to obtain the “desirable” residual stresses with the aim to inhibit fatigue crack initiation and crack propagation as function of the thickness. A novel application of residual stresses induced by LSP process to obtained similar or improved fatigue performance in structural joints after cold expansion technique will be presented. When compared with cold-expansion of holes in structural joints subjected to high secondary bending, LSP is a highly flexible technology for the introduction of “engineered” residual stresses capable to extend the fatigue onset not otherwise possible with cold expansion. Current LSP systems are not compatible with commercial aircraft maintenance environment. Rigid and complex mirror-based beam delivery system may be a showstopper for applying LSP treatment at fatigue critical components for in-service commercial aircraft during standard maintenance and repair operations. To make LSP applicable at Maintenance Repair Overhaul (MRO) and ensure reasonably simple setup and easy transportability requires developing a “portable” device. A newly developed low energy portable equipment (LEOPARD™) for MRO deployment capable of LSP in fully assembly aircraft will be presented. LEOPARD™, is the first around the world laser peening portable equipment receiving ATEX (Atmosphere Explosive Environment) certification for CLASS IV laser.