Composite Materials Research Progress

Damage Evaluation and Residual Strength Prediction of CFRP Laminates … 193
stacking sequences were produced, respectively [0,90,45,-45]s and [90,0,45,-45]s , as shown
in figure 22.
Analogous tensile tests were run, for each stacking sequence, on nine undamaged
specimens cut from undamaged zones of the same plates in order to get reference values.
Tensile tests were performed by means of the same servo-hydraulic machine in
displacement control with a head speed of 0.02 mm/s and a gauge length of 150 mm. Also in
the case of tensile tests the AE have been monitored by a Physical Acoustic Corporation
(PAC) PCI-DSP4 device with two transducers PAC R15, setting the amplitude threshold at
40 dB.
Case study 2: Results and Discussion
Transversal load test
In figure 23 are shown macro photos of the loaded side (a) and of the back side (b) of
damaged plates for the three different damage levels.
Figure 23. Damaged zones (inside the dotted circles) for the three damage levels (Low, Medium, High)
on the loaded surface (a) and on the back surface (b).