Mechanical analysis and bionic improvement on buckling of CFRP tubes with high energy absorption capacity

Fiber-reinforced composite tubes have remarkable advantages in energy absorption due to the high specific strength, stiffness, and fracture energy, etc. While, the energy absorption capacity is severely dominated by buckling deformation. To this end, the buckling behaviors and corresponding mechanism of CFRP (carbon fiber reinforced polymer) tubes are systematically investigated in this work. Furthermore, an advanced bionic method referring to bamboo and human bones is adopted to improve the buckling. To effectively analyze the buckling, drop weight impact experiments and corresponding numerical simulations are carried out. The results show that the specific energy absorption (SEA) of CFRP tubes is significantly affected by the diameter-to-height ratio and fiber ply direction, and the influencing mechanism is excessive buckling caused by the geometric characteristics and brittle failure of CFRP. At last, the SEA of CFRP tubes were improved through bio-inspired multi-layered metal/composite hybrid, where the buckling is suppressed reasonably well. The conclusions drawn would be inspiring or guiding the optimal design of high energy-absorbing composite tubes in engineering application.