Characterization of moisture effects on novel agglomerated cork core sandwich composites with fiber metal laminate facesheets

Abstract

A sandwich material would be an attractive structural candidate for marine applications as long as it can retain its environmental durability. However, the susceptibility to moisture attacks is still the major drawback of sandwich materials in comparison to the single skin laminates. Hence, this paper aims to study the effect of moisture absorption on the mechanical behavior of a newly developed sandwich structure, which is intended for use as a water-resistant constructive system in marine industries. For this purpose, an eco-sandwich material consisting of fiber metal laminate facesheets bonded to a core of agglomerated cork was successfully designed and manufactured. To investigate the moisture effects on possible mechanical degradation, a certain number of sandwich specimens were immersed in distilled water for a period of 100 days. For comparison, a sandwich structure with the commercial E-glass–epoxy facesheets was also manufactured and exposed to the aforementioned conditioning process. Eventually, the flexural, buckling and impact behaviors of the conditioned specimens were evaluated and compared with those of dry specimens. Results showed that that water immersion exposure effectively contributed to reducing the mechanical properties of sandwich specimens with E-glass–epoxy facesheets compared with those having fiber metal laminate facesheets. Moreover, it was found that the excellent mechanical properties of the fiber metal laminates in combination with the high environmental durability of agglomerated cork offer a synergistic effect yielding a sandwich martial with various advantages in terms of eco-friendly, high environmental resistance, and superior mechanical properties.

Influence of nanoclays on water uptake and flexural strength of glass–polyester composites

“…It is well known that when polymer nano-composites (PNCs) are immersed in water or exposed to moisture, moisture gradually penetrates to the polymer and may adversely affect the properties of the composite. [14][15][16] Katnam et al 17 studied the effect of moist environment on the static and fatigue behaviors of rubber-toughened epoxy adhesive. Results indicated that both the static and fatigue resistances of adhesively bonded joints are considerably affected by the moisture absorption.…”

Experimental and finite element analysis of the impact response of agglomerated cork and its intraply hybrid flax/basalt sandwich structures

“…Concerning work environment, some studies wondered about the harsher conditions that agglomerated cork sandwich structures may face when employed in marine environment thus assessing the effect of water absorption [46,131] and salt fog exposure [132,133] on their quasistatic and dynamic response. It must be considered that cork enclosure between skin laminates tends to reduce water uptake and the exposure to salt fog, but impact events can cause skin damage and perforation phenomena which can imply a direct exposure of the core to the work environment.…”

The Moisture Diffusion Equation for Moisture Absorption of Multiphase Symmetrical Sandwich Structures

“…Although the experimental works have been done on the moisture diffusion behaviors of sandwich structures [19][20][21][22], few analytical works have been done to describe their moisture diffusion behaviors, especially for sandwich structures which have a multiphase structure. Yu and Zhou [23] studied two-phase moisture diffusion equations for the moisture diffusion behaviors of flax/glass fiber reinforced composites.…”