| This investigation evaluated the fibre metal laminate GLARE as a possible patch material for field repair of composite laminates. A two-dimensional finite element model was used to simulate the mechanically fastened patch repair of typical penetration damage in a wing skin laminate. The effects of varying patch parameters such as thickness, fastener diameter, and geometry were considered. The analysis results were compared with experimental data gathered from biaxial testing of repaired biaxial test specimens. Patch effectiveness was judged by the decrease in strain near the damage after patching, and the strain introduced by the fastener holes in the composite and the patch. Thicker patches resulted in a reduction of the stress concentration near the damage but caused higher strain at the fasteners. Changes in fastener diameter did not significantly affect the results. By using a moderate modulus material, GLARE, in place of a stiffer material, titanium, the repaired area experienced lower strain. A GLARE patch does not attract as much load to the damaged area and is sufficiently strong to carry the required load without failure. This technique of soft patching has potential benefits in repairing composite laminates. |
