PSI - Issue 77

Claudia Barile et al. / Procedia Structural Integrity 77 (2026) 3–10 Barile and Kannan/ Structural Integrity Procedia 00 (2026) 000 – 000

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3. Results and Discussions 3.1. Recovery of Flexural Properties

The flexural properties of the self-healing composite specimens are evaluated from the stress-strain curves. Representative stress-strain curves of each specimen group are presented in Fig. 2. The flexural strength of virgin specimen is, as anticipated, higher than the damaged and healed specimens. While progressive damage, in the form of drop in flexural stress, is seen in all specimen groups, the number of progressive damage stages before failure in virgin specimen is lower than the other groups. The damaged specimens DS-1 and DS-2 have significantly poor flexural responses compared to the virgin group. Since the unstable damage state is created in these specimens, this response is anticipated. DS-1-Healed shows a marginal improvement in its flexural response. The flexural strength, strain at which stress is maximum, and number of damage progression stages is marginally better than the DS-1 specimen. Similarly, the flexural performance of DS-2-Healed is better than DS-2 specimen.

Fig. 2 - Representative Flexural Stress-Strain Curves of Self-Healing Composite Specimen Groups.

The recovery of flexural performance is quantitatively analysed by comparing the flexural strength and flexural modulus of the specimens. The results are presented in Fig. 3. While the healing process have recovered the flexural strength in both DS-1-Healed and DS-2-Healed specimens from their respective damage states DS-1 and DS-2, there is only a marginal recovery of the Flexural Modulus. In addition, the flexural strength and modulus of DS-2 is unexpectedly higher than DS-1. It must be noted that DS-1 is created by loading the specimen up to 10% σ f and DS 2 is created by loading up to 30% σ f . Nevertheless, the loading causes an unstable damage state in the specimen, which in turn results in better performance of DS-2 and DS-2-Healed groups compared to the DS-1 counterparts.