Crashworthiness of Circular Tubes with Structurally Graded Corrugations 2016-28-0050

Corrugated tubes are one among the different types of energy absorbers being used for the protection of passengers during impact /crash events of vehicles. Present work is primarily focused to analyze the effect of the variations of wavelength and amplitude of corrugation along the length of the tube on the crashworthiness of the tube. The circumferential corrugations in the tubes are graded by varying two parameters - wavelength and amplitude individually as well as simultaneously using different sinusoidal corrugation functions. The dynamic impact analysis has been carried out using LS-DYNA FEM code using shell elements for meshing and Magnesium alloy AZ31 as material. Energy absorbed, initial peak force, mean force and stroke length are the parameters used in this comparative study. It is observed that the initial reaction forces as well as the ratio of the mean reaction force to peak load changes with the grading of corrugation. Some interesting results are observed showing only small fluctuations about the mean force in the load-displacement curve and elimination of the initial peak load. Post analysis study results in the classification of tubes on the basis of energy absorption capability and lower initial peak reaction force. All the corrugated tubes have shown lower initial peak forces and a higher crush force efficiency i.e. better ratio of average reaction force to peak reaction force. These structurally graded corrugated tubes are a definite improvement over plain circular and corrugated tubes.