Composite Materials Research Progress

250
Maria Pia Cavatorta and Davide Salvatore Paolino
accumulation. For impact energies that cause perforation, the DuI maintains a very low value
up to a few impacts before perforation when it rapidly increases (Figure 12).
DuI
0.10
0.08
0.06
0.04
0.02
0.00
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Impact Number
GVP90_12.31
CE90m_4.00
Figure 11. DuI data for repeated impact tests performed on GVP90_12.31 and CE90m_4.00 laminates.
Impact energy: 24.5 J.
DuI
2.0
1.5
1.0
0.5
0.0
1 3 5 7 9 11 13 15 17 19
Impact Number
GVP90_12.31
CE90m_4.00
Figure 12. DuI data for repeated impact tests performed on GVP90_12.31 and CE90m_4.00 laminates.
Impact energy: 98 J.
Data in terms of DD and DI are reported in Figures 13 and 14. To avoid confusion, data
are organized for single impact energies and single laminates. DD and DI data are plotted
together to favor a comparison between the two variables. For energies that cause no