Response of axially stacked square tubes to axial impact loads
Latin American Journal of Solids and Structures
Blast Impact and Survivability Research Unit (BISRU), Department of Mechanical Engineering, University of Cape Town, Rondebosch, Private Bag, 7701, South Africa
The crushing and energy absorption characteristics of thinwalled specimens consisting of single and axially stacked mild steel square tubes are investigated by the performance of quasi-static and dynamic axial crushing tests. Two tubes are axially stacked either by means of weld or a plate. Welded specimens comprise of two tubes of equal length axially stacked on each other and seam welded around all four sides. Plate divided specimens consist of two tubes of equal length axially stacked with a rigid mild steel plate in between them. The rigid plate has a thickness of 10mm and acts as an elastic medium for energy to be transferred from the top tube to the bottom tube during axial loading. All tubes have square cross-sections of 50mm×50mm and nominal wall thicknesses of 1.6mm. The lengths of the tubes range from 250mm to 1700mm encompassing the three main modes of buckling; namely progressive, Euler and the transition mode. The global slenderness or length-to-width ratio (L/C) is investigated with regards to buckling modes. Welded tubes behave very similarly to single tubes. Plate-divided specimens exhibit two high peak loads with a slightly increased mean crush load compared to single and welded tubes.