Face sheet materials were first ground with 180 grade sandpaper in
accordance with the 3M 2216 adhesive user instructions, and then the
aluminum plates were cleaned with acetone, while the composite plates
were cleaned with isopropyl alcohol.
Jen et al. indicated that an 0.7 kg/m2 amount of
adhesive achieved maximum flexural strength 16;
therefore, 7.5 g of adhesive, corresponding to that amount, was applied
to the cleaned side of the face sheet materials with a spatula. After
applying adhesive to a single face, the samples were kept under a 2.5 kg
weight for 24 hours, and then adhesive was applied to the other face.
Before performing tests, all specimens were left at room temperature for
1 week to ensure completion of the adhesive curing process.
The mechanical properties of the 3M 2216 adhesive, and the Al-5754 and
Al-3003 alloys are shown in Table 2, while the mechanical properties of
the CFRP composite are shown in Table 3. E1 and
E2 are the longitudinal and transverse elastic modulus,
ν12 is Poisson’s ratio, G12 is the shear
modulus, and XT and XC are
longitudinal tensile and compressive strengths, respectively.
XC, YC and S are longitudinal
compressive strength, transverse compressive strength and shear
strength, respectively.
Table 2. Mechanical properties of the adhesive, and the Al-5754 and
Al-3003 alloys