PSI - Issue 52

Valerio Acanfora et al. / Procedia Structural Integrity 52 (2024) 340–347 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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An in-section view is useful in order to identify delaminated areas, which occur due to the fact that the sub laminates above and below a particular interface are characterized by different bending stiffness [10]. However, only small-scale delaminations can be observed as the impact energy is relatively low: hence, a 50 J impact energy model has been implemented to validate the reliability of the cohesive parameters. In this instance, the size and the shape of the delaminations increases exponentially, and some elements in the specimen mesh have been removed as they overcome the maximum damage that can be sustained (Figure 9).

Figure 9: In-section view for the model with eight elements through thickness, with cohesive parameters.

Models featuring both intra-laminar and inter-laminar damages present the highest degree of complexity, resulting in a significant increase in computational time. However, these analyses demonstrate the reliability of the established methodologies, as they yield results that are consistent with the experimental data (Figure 10). Discontinuities in the force-time history followed by oscillations indicate the onset of delaminations and significant alterations in stiffness.

Figure 10: Comparisons between the two models with cohesive parameters.