Bonded Composite Patch Design for Aircraft Structures Exhibiting Cracking and Corrosion

Many military and civilian aircraft are expected to operate beyond their designed life expectancy. as a result, the development of reliable and cost-effective repair techniques for deteriorating components in aging aircraft is of great interest. the application of bonded composite material patches to restore cracked and corroded metallic airframes has been shown to be an effective repair technique for increasing the durability and damage tolerance of the repaired structure. Composite Repair of Aircraft Structures (CRAS) is a computer program that is currently being used to design bonded patches for damaged metallic structures. the results are presented for a study whose objective was to extend the applicability of the CRAS program to include bonded patch design for aircraft structures that have sustained adjacent cracking and corrosion damage. Patch designs were developed for three different cracking and corrosion configurations. Composite patches were manufactured according to the designs developed and applied to damaged aluminum panels using a hot-bonding device. Patched and unpatched panels were loaded to failure using a material testing system (MTS) 880 machine. in all cases the failure loads of the patched panels exceeded those of corresponding unpatched panels. These results validated the patch design procedure developed herein for the configurations considered.