Analytical modeling of Fiber Metal Laminate stiffened by bonded straps

Fiber Metal Laminates(FMLs) consist of thin metal sheets bonded together with pre-impregnated fiber layers and show an excellent fatigue crack growth behavior compared to the equivalent monolithic metal. The fibers are insensitive to the occurring fatigue loads and remain intact while the fatigue cracks occur in the metal layers. The composite nature of FMLs creates a second load path, the bridging fibers, which attract load from the cracked metal reducing the fatigue crack growth rate. This work presents the investigation into the fatigue crack propagation and delamination growth of the Fiber Metal Laminate Glare stiffened by external titanium straps. This investigation covers both the theoretical analysis and experimental investigation of the crack growth and delamination growth phenomena in stiffened Glare panels. The main concept in this work is that the effect of external stiffening elements can be described with the superimposition principle, independently of the geometrical disposition of the stiffeners. This work represents the extension towards stiffened structures of the analytical prediction model for Glare flat panel developed by René Alderliesten.

Autorentext

Riccardo Rodi is PhD researcher at the Faculty of Aerospace Engineering of TUDelft since May 2007. He is currently working on the modeling of the residual strength of FMLs. René Alderliesten is assistant Professor at the Faculty of Aerospace Engineering of TUDelft. Luigi Lazzeri is Professor at Aerospace Department of University of Pisa