Influence of Linear and Stepped Variation in Wall Thickness on the Energy Absorption Efficiency of Square Tubes Under Axial Compression

Abstract

AbstractNowadays, energy conservation and safety have become the main directions for vehicle research and development. In this connection, thin-walled square tubes have been extensively used as energy absorbers in automobile vehicles. In case of frontal crash accidents, these tubes are expected to collapse and absorb crash energy. If these tubes deform at very high crush forces, there is high risk and damage to the vehicle occupants. Hence, the design of such tubes is important with minimum peak crush force with an enhanced energy absorption capacity. Introducing thickness variation in thin-walled tubes is one of the techniques to minimize the initial peak crush force. In this research work, square tubes with linearly (LVST) and stepwise (SVST) varying wall thickness tubes were manufactured from commercially available AA6063 extruded tubes in the “M1TR” vertical milling machine with the help of slip gauges in providing gradients and steps. Subsequently, the crushing behaviors of LVST and SVST tubes were experimentally characterized and their initial peak crushing force (IPCF) and energy absorption (EA) were evaluated. It was found that variation in the wall thickness of tubes has a significant effect on their IPCF and EA. IPCF of LVST and SVST tubes were reduced by 24–67% and 30–71% respectively compared to uniform thickness (UT) tubes. At the same time, enhancement of SEA of about 6.84% was witnessed. The results evidenced that LVST and SVST tubes can improve the deformation behavior and be used as energy absorbers in place of uniform tubes in automotive fields.KeywordsLinear varying thickness tubeStepped varying thickness tubePeak crushing forceEnergy absorption