Determination of the fracture behaviour of axial splitting tubes and the numerical prediction of their energy absorption capabilities

作者：Moreno C^*; Beaumont R; Hughes D J; Williams T; Dashwood R

来源：International Journal of Crashworthiness, 2015, 20(2): 191-199.

DOI：10.1080/13588265.2014.997000

• digital image correlation
• splitting tubes
• fracture strain
• energy absorber
• finite element analysis

Axial splitting of tubes has been used as an energy absorption mechanism since the 1980s. The simulation of the fracture behaviour of splitting tubes, key to accurately predict the splitting mechanism behaviour, has not been studied. This paper explores the fracture strain and the strain state local to the tip of the crack of the splitting tubes, and examines the accuracy of a numerical crush model using the acquired strain fracture data. The measurement of the fracture strain and the strain state local to the tip of the crack on the E355 steel tube surface was performed with a digital image correlation method. The tubes were fabricated to simulate the axial splitting mechanism used in railway energy-absorbing applications. Four- and six-notch initiators were cut in the specimens. The fracture strain data were included in a LS-DYNA numerical model. The friction coefficient was inferred by correlation of the simulation to the quasi-static compression test results. It was found that the digital image correlation method determined the fracture strain as epsilon(f) = 0.60 for both types of specimens, with four and six notches. The strain ratio measured by the digital image correlation software was alpha = -0.03 and -0.11 for specimens with four and six notches, respectively. The inferred friction coefficient value was mu = 0.07 for both specimens with four and six notches. This value agrees with the value quoted in the literature for a similar energy-absorbing mechanism.

• 出版日期2015-3-4