Lateral (diametral) crushing of steel circular cylindrical tubes, welded to the platens

摘要

As parts of a more elaborate system, liable to receive energy and expected to absorb it in a smooth manner, a series of steel circular cylindrical tubes were crushed in lateral (diametral) quasi-static compression. Due to the condition of placement of the tubes in the system which must be welded to the supporting top and bottom plates, the individual single tubes, the subject of this paper, were initially tested under the same condition. That is, welded to the supporting plates, and diametrally crushed under compression. As expected, the results were totally different from those of the tubes simply crushed laterally between parallel platens without being welded to them, available in the literature, also obtained in this work. These include the mode of collapse, the total and specific energy, and the rest of collapse parameters. In order to study the adverse consequences of welding on various collapse characteristics of the tubes, similar specimens were tested after being subjected to a stress relieving (annealing) process. These adverse effects, which are mainly the brittleness of the material and developed cracks at the welded areas and their vicinity, and also the residual stresses developed in the same areas, are more pronounced for tubes of smaller diameters. Such phenomenon may be attributed to the less exposure to the air and hence the lower rate of cooling of such tubes. In addition to removing these effects, annealing reduces the average crushing load experienced by the welded tubes, leading to more tolerable decelerations, in those circumstances where welded tubes are used as energy absorbers.