Composite Materials Research Progress

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DD, DI
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Maria Pia Cavatorta and Davide Salvatore Paolino
y = 1.1E-01x + 3.2E-01
R 2 = 1.00
1 2 3 4 5
Impact Number
DD DI
Figure 14a. Comparison between DD and DI data in repeated impact tests performed on CE90m_4.00
laminates. Impact energy: 98 J.
DD, DI
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
y = 9.3E-03x + 1.9E-01
R 2 = 0.96
1 3 5 7 9 11 13 15 17 19
Impact Number
DD DI
Figure 14b. Comparison between DD and DI data in repeated impact tests performed on GVP90_12.31
laminates. Impact energy: 98 J.
Figure 14a reports data for the CE90m_4.00 laminate tested at an impact energy of 98J.
Perforation is achieved at the 5 th impact. As it can be observed, the DD constantly increases
impact after impact to reach a value of about one at the 4 th impact, where laminate penetration
is achieved. DI values increase at a constant rate up to the 3 rd impact to then grow very
rapidly and reach the value of one at laminate perforation. This trend is more evident in
Figure 14b, for which perforation is achieved at the 19 th impact. Up to the 17 th impact, the DI
slowly increases at a constant rate impact after impact. In the last two impacts before