Effects of material non-linearity on the structural performance of sandwich beams made of recycled PET foam core and PET fiber composite facings: Experimental and analytical studies

This paper presents the results of experimental and analytical studies on sandwich beams subjected to three-point bending beyond their limit of proportionality. The sandwich beams were composed of polyethylene tere-phthalate (PET) fiber-reinforced polymer (FRP) composite facings and recycled PET (R-PET) foam core made from post-consumer plastic bottles. The study tested three R-PET core densities (70, 80, and 100 kg/m3) and compared the results to a control group with 100 kg/m3 core density and glass FRP facings. The beam geometry and testing set-up were consistent throughout the study, with 12 beams tested in total. The results showed that all specimens exhibited non-linear load-deflection behavior, resulting in developing a non-linear analytical model using decreasing secant elastic and shear moduli under increasing loads. The proposed model was vali-dated, and a parametric analysis was performed to evaluate its mechanical performance under different con-ditions, including variations in span length and the thickness of the core and facing components. Additionally, the study created a novel failure mode map to predict the failure mechanism of the sandwich panels based on core density and the PET FRP facing thickness to span length ratio, considering the non-linear behavior of both components. As a result, this study provides valuable insights into using recycled materials in construction, contributing to reducing plastic waste and mitigating environmental impact.

Automated summary

This paper presents experimental and analytical studies on sandwich beams subjected to three-point bending beyond their limit of proportionality. The beams were composed of PET FRP composite facings and R-PET foam core made from post-consumer plastic bottles. The results showed non-linear load-deflection behavior, and a non-linear analytical model was developed. A parametric analysis was performed to evaluate the mechanical performance under different conditions, and a failure mode map was created. This study provides valuable insights into using recycled materials in construction and reducing plastic waste.