Energy Absorption Capability of Hybrid Fibers Reinforced Composite Tubes

Lightweight fiber-reinforced composites (FRPs) do not exhibit the ductile failure mechanism associated with metals. FRPs absorb lots of energy through progressive crushing modes by a combination of multi-micro-cracking, bending, delamination, and friction. However, FRPs have not been used as energy absorption components on a large scale, one of the most important reasons being their high manufacturing costs. In this study, carbon fiber, glass fiber, and aramid fiber were chosen as reinforcements and a commercial epoxy resin was chosen as matrix to manufacture nine types of different structures and reinforcement forms of hybrid fiber reinforced composite tubes through a highly productive and low-cost winding method. Then specimens were kept under 100 °C conditions for 100 h, 200 h, and 400 h, respectively. The effects of crushing speed, temperature treatment, reinforced forms and structures including hybrid ratio, fiber orientation, and thickness of tube wall on energy absorption capabilities were investigated by quasi static and dynamic compression tests. Optical microscope observations of cross section were taken to analyze the mechanism of failure. By optimizing different hybrid methods, ratio, and reasonable geometry shape of composites, low cost and high energy absorption components with specific energy absorption (E s ) reaching 100 kJ/kg in quasi-static tests and 82 kJ/kg in dynamical tests could be manufactured for real applications in vehicles.