Effect of Semi-Apical Angle on the Crush Mechanics of Metallic Bi-Tubular Tubes under Dynamic Axial Loading

Abstract

Aerospace and automotive industrial advancement demands high energy absorbing structures for the human
and equipement safety during transportaion and accidental emergencies. Thin-walled metallic tubes
applications in the structures serve the purpose by absorbing energy during such dynamic scenarios. A new
concept is presented in this study, involving bi-tubular tube with outer straight cylinderical tube and inner
tube with semi-apical angle and response is monitored for dynamic axial loading. The outer and inner tubes
are connected with 4 straight stiffeners. The inner tube semi-apical angle named as β is varied from zero to 2
degrees and its sensitivity in energy absorption is studied.In total five configurations are studied with first
configuration havingβas zero degree. The second and third configuration are with βas one degree with
distinct feature that in third configuration the tube is inverted. Same is true for the fourth and fifth
configuration with βas two degrees.The mass in each configuration is kept constant by adjusting the
thickness of the stiffeners. Deformation modes, specific energy absorption and crushing force efficiency are
determined for each configuration and contribution of β is discussed. An analytical approach to observe the
sensitivity of β is also presented. The results are compared with the experimental and theoratical results to
show the effectiveness of the proposed configurations.
Keywords:Bi-tubular, Semi-ApicalAngle, Energy Absorption, Dynamic Axial Loading.