Energy absorption performances of glass-fibre reinforced polymer cylindrical structures under hoop tensile loading

Abstract

Composite structure creates lightweight with a high strength-to-weight ratio material. This structure allows design flexibility in fibre orientation and the number of plies. Leveraging the design and performance of glass-fibre reinforced polymer (GFRP) pipes is essential to increase their competitiveness against metallic structures. However, GFRP has a wide range of failure modes and is less intuitive in the design phase than isotropic materials. A lack of practical design and analysis in composite materials directly compromises operational safety, especially when subjected to extreme internal loading conditions. The primary objective of this study was to determine the energy absorption performance of GFRP cylindrical structures under hoop tensile loading through experimental and numerical methods. The split disc test was conducted to determine the hoop tensile stress of various-sized GFRP pipe rings. The numerical results were compared to the experimental ones to validate the finite element method (FEM) model in terms of force-displacement curves, and deformation mode. The comparison showed an acceptable correlation in numerical analysis. The validated FEM model was then used to conduct a series of parametric studies. These studies showed that increasing the core thickness and winding angle significantly affects energy absorption performance under hoop tensile loading. A 171% increase in specific energy absorption (SEA) capacity can be seen when the core thickness was increased from 5.23 mm to 15 mm. A superior performance was obtained by involving a greater amount of material in energy absorption process. On the one hand, a 61% increase in SEA was observed when increasing the winding angles from ±54.5° to ±75° due to the parallel high angle with the force direction. On the other hand, increasing the layer counts from 14 to 25 layers yielded a 0.7% decrease in SEA. Increasing the number of layers reduces the ply thickness-to-resin ratio, leading to stiffer structure with increasing microcracks. Above all, the current research makes a critical contribution by developing a validated FEM model as a design tool for evaluating the performance of GFRP by varying controllable parameters prior to fabrication. This contribution would significantly reduce manufacturing time and material waste while optimizing design efficiency.