PSI - Issue 37

M.P. Silva et al. / Procedia Structural Integrity 37 (2022) 841–846 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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The impact energy's effect on the maximum displacement is discussed. The maximum displacements increased with the impact energy, and the maximum displacement grew by around 150 % throughout the range of impact energies investigated. Finally, the restored energy is never equal to zero, implying that the absorbed energy and the impact energy are never equal. As a result, the impactor's complete penetration was not achieved since the excess energy was employed to bounce it. Higher energies, on the other hand, appear to encourage lower restored energy (also known as elastic recuperation), which, according to Amaro et al.(A. Amaro et al., 2013; A. M. Amaro et al., 2013), is due to the higher damage produced by impact loads. For example, considering the range of energies studied, the restored energy decreased around 72 %, which shows the severity of the damage introduced into the composite laminate.

Table 1 - For different impact energies: Maximum impact load, Maximum displacement, and Restored energy. Impact Energy ( J ) Maximum Load ( kN ) Maximum displacement ( mm )

Restored Energy ( % )

Average

Std Dev

Average

Std Dev

Average

Std Dev

4 8

2.09 3.09 3.43 3.59 3.93 4.12 4.53 4.83

0.31 0.23 0.26 0.32 0.29 0.15 0.17 0.23

3.97 5.45 6.30 6.75 7.98 9.03 9.71 9.93

0.60 0.63 0.60 0.62 0.56 0.58 0.64 0.62

50.53 41.18 35.08 31.18 25.20 22.33 16.55 14.42

3.20 3.56 4.10 4.23 3.87 4.53 3.98 4.18

10 12 16 20 24 28

Figure 2 illustrates the influence of exposure time and solution type on this parameter based on the link that can be established between the restored energy and the severity of the damage caused by the impact loads (A. Amaro et al., 2013; A. M. Amaro et al., 2013).

Figure 2 - Influence of the exposure time on the restored energy for H 2 SO 4 , seawater, and diesel.

Longer exposure times result in lower percentages of recovered energy, as shown in Figure 2, and some solutions are more aggressive than others. These findings are consistent with those reported in the literature (A. Amaro et al., 2013; A. M. Amaro et al., 2013; Mortas et al., 2014), and may be explained by the absorption, penetration, and reaction that occurred between solutions and composite constituents (Mahmoud & Tantawi, 2003). Finally, the lowest maximum bending stress (143 MPa) was used in order to assume longer fatigue lives in order to analyze the real and expressive influence of hostile solutions on residual fatigue life. In reality, at higher stress levels, fibres dominate the damage mechanisms, but only the damage propagation generated by the impact load is predicted at the