Figure 3. 6AL10a-b-c specimen images obtained after 5 Joules of
impact energy
Fatigue Tests
Fatigue tests were conducted using Shimadzu Servo-Hydraulic Fatigue test
equipment with a 100 kN load cell. First, the fatigue behaviors of the
materials used in producing the sandwich composites were determined
using a 5 Hz frequency. Load was applied to specimens as a sine wave and
R (σmin/σmax) of 0.1 was used. Fatigue
tests were performed for aluminum, the 3M 2216 adhesive and the
composite materials, for values below static damage loads. Figure 4
shows stress vs. cycles to failure graphs for the Al 5754 face sheet,
the 3M 2216 adhesive and the CFRP.