Paper Title
Adhesive Effect On The Performance Of The Repair Efficiency Of Bonded Aluminum Alloy

Abstract
Aircraft cracked structures life can be extended with the reinforcement of composite and metallic patches using bonding techniques. Effect of the adhesive on the performance of the patch repairs was evaluated by conducting a comparative study on cracked aluminum plates. Fatigue tests were conducted on 2 mm thick specimens under a maximum surface load of 120 MPa for both repaired and unrepaired specimen configurations at stress ratios of R= 0 and R= 0.1 using 20 Hz frequency. The fatigue life of the specimen is affected by the stress ratio in both cases i.e. patched and unpatched case. As the load ratio increases, the fatigue life increases for both repaired and un-repaired specimen. A numerical study of some tested configurations has been conducted using Franc2D. The numerical results for unpatched cases are in good agreement with the available analytical solution. It can be observed from the numerical investigations that there is a drastic reduction in SIF after specimen reinforcement. The maximum observed reduction in SIF after patching was around 65%. Keywords—Crack length (a), Stress ratio (R), Stress intensity factor (SIF).