Axial crush behavior and energy absorption capability of foam-filled GFRP tubes manufactured through vacuum assisted resin infusion process

• We developed a foam-filled GFRP tube by vacuum assisted resin infusion process.
• Test was conducted to prove the effectiveness of the energy absorption capability.
• The initial stiffness, stroke efficiency and energy absorption were investigated.
• Analytical model was proposed to estimate the axial strength of foam core.
• This kind of composite tubes can be used in practice.

Foam-filled circular metallic tube has been widely used in safety design of automobile, space craft recovery and so on due to its advantage of high energy absorption. But poor chemical stability and easily oxidized of metal materials seriously threaten the durability and safety of the traditional metallic tube. The application of fiber reinforcement polymer (FRP) can effectively address these issues. In this paper, a simple and innovative foam-filled GFRP tube, fabricated by vacuum assisted resin infusion process, is proposed to enhance the durability and improve the energy absorption capacity. An experimental study was conducted to validate the effectiveness of this kind of absorptor for increasing the energy absorption capacity. Meanwhile, the influences of GFRP skin thickness, diameter of tube, foam density and fiber orientation angle of GFRP mat on failure mode, initial stiffness, stroke efficiency and specific energy absorption were also investigated. An analytical model, considered the confinement effect on foam core and local buckling of GFRP skin, was also developed to predict the ultimate peak strength of foam-filled GFRP tubes. The experimental and analytical results were shown to be well matched.