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International audience; This work presents an experimental investigation of the post-fire flexural strength of Filament-wound Glass Fiber Reinforced Polymer (GFRP) tubes manufactured by CTRA Company. These tubes are assembled according to both the NFT57-900 and DIN-16966 standards’ recommendations. To this end, flexural tests have been carried out on butt-to-butt assembled tubes, before and after fire endurance tests. To gain a better insight into fire-induced damage mechanisms, thermal analysis (DSC and TGA), FTIR analysis tests, as well as Scanning Electron Microscope (SEM) observations have been conducted. The experimental results revealed that a water leakage was observed prior to the recommended threshold time by the International Maritime Organization (IMO) resolution. It has been also confirmed that flexural properties of the GFRP tube are degraded after the fire tests. Furthermore, a quantitative comparison for both filament tubes assembled according to the NFT and DIN standards confirms that the NFT ones depict higher resistance. Finally, damage investigation reveals that the main observed forms of damage occurring during this experiments are delamination and matrix cracking phenomena. The main novelties of this work are (a) extending the classic analysis carried out on simple composite plate to cover water-filled GFRP assembled tubes subject to fire endurance test, and (b) the experimental investigation of DIN and NFT butt welded joined pipes under three point loading prior and post fire endurance test.

In recent years, material scientists have been focusing on the utilization of materials from natural resources due to environmental concerns. In the same context, the aim of this work is to evaluate impact response, sound absorption behavior, and vibration damping characteristics of natural-based composite sandwich made of flax as skin reinforcement and agglomerated cork as core. Vacuum bagging method was used for manufacturing composite sandwiches with different cork densities of 240, 280, and 340 kg/m3. Composite sandwiches have also been manufactured by using glass as skin reinforcement for comparison. Low velocity impact test was conducted and found that glass fiber reinforced composite sandwich required 73–77% more energy to perforate when compared to the flax fiber reinforced composite sandwich irrespective of core density. Flax fiber reinforced composite sandwich has 45–96% higher sound absorption capacity and 27–32% higher vibration damping ratio than glass fiber reinforced composite sandwich irrespective of core density. This is due to multiscale structure and cellular nature of the flax fiber and the cork materials, respectively. These enhancements in sound and vibration are accomplished with just little forfeits in perforation energy. This study recommends that, if optimized, the natural-based composite sandwich could be an ecologically appealing answer for automobile and construction applications, where impact behavior is important, along with sound and vibration properties.