Washington, September 9 : Researchers at the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research IFAM in Bremen are exploring how useful a combination of riveting and adhesive bonding can be in the development of lighter aircraft, which will consume less fuel and, thereby, help reduce carbon dioxide emissions.
Dr. Oliver Klapp of the IFAM points out that, to create lighter planes, aircraft manufacturers are pinning their hopes on particularly lightweight construction materials that include fiber composite plastics, particularly carbon-fibre reinforced plastics (CFRPs).
The researcher says that whenever two CFRP components have to be joined together, this has so far been accomplished primarily by riveting.
"Rivet holes are a problem, particularly in CFRP structures. They disturb the flow of forces in the CFRP structures and reduce the load-bearing capacity of the material," he says.
Klapp says that his team has developed a state-of-the-art C-clamp riveting machine that can enable the necessary rivet holes, complete with one or two-part riveted bolts, to be installed accurately, and automatically in compliance with aviation standards.
He says that the advantages of hybrid joining are obvious: the CFRP materials are not riddled with so many rivet holes.
The particularly high load-bearing capacity of these materials is more effectively brought to bear in the truest sense of the word, because bonding results in a more effective, all-over distribution of forces, the researcher adds.
Presently, the aviation industry does not rely exclusively on bonded components and assemblies, and Klapp agrees that riveting will persist.
"It's true that riveting will not be eliminated from aircraft construction in the next several years," he says.
Klapp, however, adds that soon it will become important for the aviation industry to incorporate structural bonding for primary structures like the airframe, the wings and the tail units.
A presentation on the study will be made at the Composites Europe trade fair in Essen from September 23 through 25.