Augmentation of crashworthiness design of circular tubular structures by engraving grooves of varying depths

The use of gradiently grooved tubes has reaped emphasis in designing of crashworthiness systems for safeguard of commuters in passenger bus collisions. Also it is very essential to improve the performances of energy absorption systems of gradiently grooved profiles. The tubular structures exhibit superior energy absorption characteristics when subjected to uni-axial loading, on contrary it is highly susceptible to global bending mode when subjected to oblique loading pattern. This work proposes a novel design to enhance the crashworthiness metrics of circular tubular structures subjected to both direct and oblique loading by the engraving of grooves in circumferential direction with varying depths. The structure with varying groove configurations has undergone quasi-static and finite element simulations. The effect of friction contact interaction between the striker and the structure and critical loading angle (theta = 0 to 30) between them on energy absorption had been explored. The outcome reveals the merits of utilizing gradiently grooved tubes with varying groove depths which may be decreased from the striker end to the stationary end over the original, uniform and gradiently grooved structures subjected to direct and oblique loading patterns. The outcome of the work facilitates designer to enhance the energy absorbing performances for different loading conditions. Lastly, the designed tubular structure as crash buffer befitted in commercial automotive bus application is considered and demonstrated successfully.