Abstract: In this work, repaired crack in 6061- T6 aluminum
plate with composite patches presented, firstly we determine the
displacement, strain and stress, also the first six mode shape of the
plate, secondly we took the same model adding central crack
initiation, which is located in the center of the plate, its seize vary
from 20 mm to 60 mm and we compare the first results with second.
Thirdly we repair various cracks with composite patch (carbon/
epoxy) and for (2 layers, 4 layers). Finally the comparison of stress,
strain, displacement and six first natural frequencies between un-cracked
specimen, crack propagation and composite patch repair.
Abstract: Repairing of the cracks by fiber metal laminates
(FMLs) was first done by some aeronautical laboratories in early
1970s. In this study, experimental investigations were done on the
effect of repairing the center-cracked aluminum plates using the FML
patches. The repairing processes were conducted to characterize the
response of the repaired structures to tensile tests. The composite
patches were made of one aluminum layer and two woven glassepoxy
composite layers. Three different crack lengths in three crack
angles and different patch lay-ups were examined. It was observed
for the lengthen cracks, the effect of increasing the crack angle on
ultimate tensile load in the structure was increase. It was indicated
that the situation of metal layer in the FML patches had an important
effect on the tensile response of the tested specimens. It was found
when the aluminum layer is farther, the ultimate tensile load has the
highest amount.