Transverse impact response of GFRP tubes filled with MWCNT-reinforced syntactic foam

Abstract

Tubular composites made of glass fiber reinforced polymer (GFRP) have been widely used in the fields of infrastructure and automobile engineering. However, such composites are vulnerable to transverse loading occurrences and their effect on structural integrity. This paper focuses on investigating the response of hollow GFRP tubes and GFRP tubes filled with syntactic foam under transverse impacts. To enhance the stiffness of GFRP tube and improve the brittleness of syntactic foams, ribs were added to strengthen the tube wall, and multiwalled carbon nanotubes (MWCNTs) were used to reinforce the syntactic foam core. The impact response of the tubes was examined by considering the influence of ribs, MWCNTs, and the impact location. Experimental results revealed that the ribs contributed to enhancing the impact resistance of both hollow and filled tubes. However, the impact of ribs on energy absorption was less noticeable for the filled tubes. Incorporating 1.2 wt.% MWCNTs in the foam resulted in significant improvements of 25 % in peak impact force and 43 % in energy absorption for the filled tubes. Changing the impact location from the tube wall to the rib led to a significant increase of 33 % in peak impact force and 18 % in energy absorption for the hollow tubes. In contrast, the impact location had a minimal effect on the overall impact responses of the filled tubes. An analytical model was developed to predict the energy absorption capability of the composite tubes. This model accurately determined the energy absorption contribution of each component within the composite tube. The predicted results demonstrated good agreement with the experimental findings, validating the predictive capability of the model. Furthermore, multiscale finite-element (FE) models were developed to simulate the impact characteristics of foam-filled composite tube specimens. The validated FE model was subsequently utilized to conduct parametric study.