Figure 5. Specimen
images obtained after three-point bending tests
There was no surface damage observed in specimen 6CFRP10a with a 0.5 mm
face sheet thickness, while face sheet material damage was determined in
the specimens with thicknesses of 1 and 1.5 mm.
The first damage type seen in core the beginning of the test is cracks
in the cell walls. With the continuation of the test, crushing of the
cell walls and adhesive damage of the cell walls were observed. With the
catastrophic failure seen in the samples, the damage has been
concentrated especially in the support areas.
Figure 6 shows applied force vs. deflection graphs for specimens with
aluminum and CFRP face sheet materials. For both face sheet materials,
increasing face sheet thickness increased flexural strength. Moreover,
for the same load values, deflection decreased due to increased face
sheet thickness. For example, in the specimens with an aluminum face
sheet, the amounts of deflection under a 2000 N load were measured to be
1.133 mm, 0.917 mm and 0.524 mm for 6AL10a, 6AL10b and 6AL10c specimens,
respectively.