Bending crashworthiness of elliptical tubes with different aspect ratio and stiffeners

Lateral car collisions are common scenarios that represent one of the top causes of passenger's fatalities and injuries. For this purpose, the current article investigates the effect of cross-sectional aspect ratio (beta) on the crashworthiness performance of elliptical profiles under lateral loads. For this purpose, structures with different aspect ratios (beta) were evaluated. Special emphasis was set on modelling progressive damage by the Johnson-Cook (J-C) failure model for aluminum 6063-T5. The accuracy of our numerical results was determined by experimental validation of a first three-point bending model. From the numerical results, an improvement of energy absorption (E-a) and crushing force efficiency (CFE) is achieved as the aspect ratio (beta) increases. In this sense, the best CFE performance (0.728) was obtained for a structure with beta = 1.50, which means an improvement of 30.59% of E-a and 9.96% of CFE relative to a circular tube. At this point, the limits for sizing of elliptical profiles in terms of (beta) were determined by practical equation. To improve even more the crashworthiness capacity of the elliptical profile with beta= 1.50, the use of plates in horizontal, vertical, and combined mode was also explored. As a result, the effectiveness of vertical ribs was demonstrated. The highest CFE performance was obtained for a structure vertically reinforced with three ribs, which allowed a further increase of CFE up to 0.805. Then a final improvement in CFE of 21.60% was computed. Finally, an application of our study to a side sill system is also investigated.