Impact of the bio content of polymeric matrices on flexural performance of sandwich beams made of PET fiber composite facings and recycled PET honeycomb core

Abstract

This paper investigates the flexural performance of sandwich beams composed of polyethylene terephthalate (PET) fiber-reinforced polymer (FRP) composite facings and a recycled PET (R-PET) honeycomb core. The study aims to analyze the effects of different factors on the flexural performance of the sandwich beams, including the variation in bio content within the polymeric matrices, different facing thicknesses, and the orientation of the R-PET honeycomb core. Three different polymeric matrices, namely a synthetic resin, a partial bio-resin, and a bio-resin are considered. A total of 30 sandwich beam specimens (300 mm long and 25 mm wide) were prepared with three different facing thicknesses (1, 2, and 3 mm) and two orientations of the R-PET honeycomb core (strong vs. weak axes) using the three polymeric matrices. The beam specimens were tested under four-point bending until failure. The facing and core materials were also tested in tension and shear, respectively, in two orthogonal directions. Significant non-linearity is observed in the behaviour of the beam specimens, which is rooted in the non-linearity of both facing and core materials. Additionally, the results demonstrate that alterations in polymer composition significantly impact the tensile properties of FRPs, which then affect the bending performance of the sandwich beams. To further corroborate experimental findings, a finite element simulation is also employed for analyzing the sandwich beams. The outcomes offer valuable insight for the designers planning to develop efficient and sustainable composite materials, thereby advancing the creation of environmentally friendly structural components.