Energy Absorption Mechanism Of Inward-folding CRRP Tube And Its Numerical Simulation

The outstanding energy absorption characteristics of carbon fiber reinforced composite material has attracted a lot of relative researches,which has been applied more and more in the energy absorbing structure in aerospace,aviation,vehicle,and vessel.However,plenty of literatures have proven that only in a progressive failure mode can it show high energy absorption,and to ensure that there is a way to introduce triggers.Good triggers can not only guarantee the happening of progressive failure,but also improve the energy absorption characteristics.In this paper a unique in-ward folding cap with double corners as a trigger.CFRP tubes with different ply orientation such as[90/0]₆,[90/-45/0/+45]₃,[90/-15][+15/-15]₅,and[90/-45][+45/-45]₅ and diameters such as 30mm,40mm,50mm,60mm are crushed and numerical simulation is conducted based on ABAQUS/EXPLICIT and its VUMAT subroutine.The results show that,under the influence of the crushing cap,the specific energy absorption（SEA）value of CFRP material can reach 60～110 k J/kg,which means it is an excellent trigger,and the trigger mechanism is that the decrease in circumference cause the compressive crack in circular direction,which is similar to“ply drop-off”.For laminate orientation,the more the fiber in longitudinal direction is,the higher SEA can be obtained.For tube diameter,the performance of 40 mm is the best.Numerical simulation using the stiffness degradation method based on crack energy and results shows good agreement with experiments.