Influence of Triggers on the Damage Characteristics and Initial Peak Load of Composite Tubular Energy Absorbers for Low-Velocity Impact Applications

Carbon fiber reinforced polymer (CFRP)-based thin-walled composite tubes used as sacrificial energy absorbers in the transportation sector are provided with triggers in design which are stress concentration zones. These triggers serve to reduce the initial peak impact load value that shall be experienced during the energy absorption process. Detailed finite element-based computations are done to study the influence of configuration and angle for the trigger designs with which the thin-walled quasi-isotropic composite tubes are proposed to be made, for slow speed impact. A trigger angle that could result in the lowest possible initial peak load can act as a stress concentration zone and cause partial damage even during slow speed impacts which might not be fatal. Hence, an optimal combination of trigger configuration and angle is suggested based on sensitivity studies.