Mechanical performance of an optimized cork agglomerate core-glass fibre sandwich panel

• Published in: Composite structures 2020-08, Vol.245, p.112375, Article 112375
• Main Authors: Reis, P.N.B., Silva, M.P., Santos, P., Parente, J.M., Valvez, S., Bezazi, A.
• Format: Article
• Language: English
• Subjects: Mechanical properties; Mechanical testing; Out of autoclave processing; Sandwich structures
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2020.112375

The experiments performed were oriented to produce and characterize a sandwich panel with an optimized composition of cork granules, obtained from industrial by-products, and a green epoxy resin. Static bending tests were performed to characterize the mechanical strength and its viscoelastic response. Stress relaxation tests evidence a decrease of the stress over the time and the experimental data can be fitted by Kohlrausch-Williams-Watts (KWW) model successfully. In terms of creep, the displacement increases and while the KWW model is preferable to the Findley model for short-term predictions, the opposite trend occurs for long-term predictions. Fatigue life was also investigated, where the damage mechanisms that govern the fatigue strength, as well as the residual mechanical properties, were characterized. Small cracks were observed under the pin load contact region, between skin and core, which grow around the cork grains and follow the direction of middle plane toward the tips of the specimen.