Composite Materials Research Progress

F peak [kN]
16
14
12
10
8
6
4
2
0
Damage Variables in Impact Testing of Composite Laminates 249
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Impact Number
GVP90_12.31
CE90m_4.00
Figure 9. Values of peak force in repeated impact tests performed on GVP90_12.31 and CE90m_4.00
laminates. Impact energy: 25 J.
F peak [kN]
30
25
20
15
10
5
0
1 3 5 7 9 11 13 15 17 19
Impact Number
GVP90_12.31
CE90m_4.00
Figure 10. Values of peak force in repeated impact tests performed on GVP90_12.31 and CE90m_4.00
laminates. Impact energy: 98 J.
Figures 11-12 report data in terms of the DuI. As in Figure 5, for impact tests with
rebound, contribution of Einitiation and Epropagation is calculated according to the definition
illustrated in Figure 4b. Figure 11 shows that for impact energies that cause no perforation,
the DuI is very low and constant throughout the test, signaling no significant damage