Quasi-static Axial Crushing Behavior of Thin-walled Circular Aluminum Tubes with Functionally Graded Thickness

In this paper, the crushing behavior of circular aluminum thin-walled tubes with functionally graded thickness (FGT) are investigated experimentally. To this aim, three different thickness grading patterns are introduced to the longitudinal direction of tubes using a grading function, and then specimens are tested by universal testing machine under quasi-static axial compression loading. In addition, to show the efficiency of FGT tubes, the quasi-static axial crushing performance of FGT tubes are compared with their uniform thickness (UT) counterparts at the same weight. The test specimens have been made of commercial quality 6060 aluminum alloy and manufactured with computerized numerical controlled (CNC) machining workbench. Initial crush force (ICF), total energy absorption (EA), specific energy absorption (SEA) and mean crush force (MCF) values are measured from the tests to infer the quasi-static axial crushing performance of the tubes. The test results showed that the energy absorption characteristics of FGT tubes are better than the UT counterparts and FGT tubes allow effective control of the energy absorption parameters when compared with the UT tubes due to their varying stiffness along their longitudinal direction.