Quasi-static crushing behaviors and plastic analysis of thin-walled triangular tubes

To study the collapse mechanism and energy absorbing ability in lateral compression, metallic isosceles triangular tubes were designed and fabricated, with the base angle varying from 30 degrees, 45 degrees, 60 degrees to 75 degrees. According to the experiments, it is found that three typical crushing modes and two critical base angles characterize the lateral crushing behaviors of the isosceles triangular tubes. Tubes with base angle smaller than 45.6 degrees are crushed without obvious fold. Tubes with base angle greater than 72.6 degrees have side-wall contact at the buckling center before forming a new shortened triangle and being folded. With the base angle between these two critical values, tubes behave the same as the equilateral triangular tube. Triangular tubes have unified energy absorbing mechanism, including six plastic hinges and one traveling plastic hinge. The mean crushing force of the tube was well predicted based on plastic analysis, supplying criterion for material selection in designing anti-impact structures. (C) 2014 Elsevier Ltd. All rights reserved.