Optimization analysis of novel foam-filled elliptical columns under multiple oblique impact loading

Thin-walled columns have been widely employed as energy absorbers for vehicle structures due to their dramatic merits of high energy absorption to weight ratios. Meanwhile, columns filled with low-density metal foams have demonstrated notable improvement on energy absorption capabilities compared with their empty counterparts. Accordingly, the present study aims to investigate and optimize the crashworthiness characteristics of novel foam-filled elliptical column (F-EC) under multiple oblique impact loading. More specifically, the finite element (FE) models of hollow and foam-filled elliptical columns (H-EC, F-EC) are first built and validated against theoretical and experimental outcomes. On this basis, a detailed crashworthiness comparison between the elliptical columns (ECs) and the circular columns (CCs), including hollow and foam-filled columns (H-CC, H-EC, F-CC, F-EC), reveals the superiority of F-EC relative to others on overall crashworthiness characteristics under multiple oblique impact loading. Next, a Taguchi-based design of experiment (DoE) is implemented to investigate the impact of column parameters of F-EC, including the sectional ellipticity e, the column thickness i and the foam density rho(f) on the column peak crushing force under axial impact loading (PCF0) and overall specific energy absorption under multiple oblique impact loading (SEAM). Subsequently, the Taguchi method coupled with grey relational analysis (GRA) is utilized to explore the optimal design of F-EC for maximizing SEA(0) and minimizing PCF0 simultaneously, which is then verified through a detailed crashworthiness comparison between the optimized design and the original design. The optimal F-EC reveals more superior crashworthiness characteristics relative to the original design and thus demonstrates enormous potential as a candidate energy absorber particularly under multiple oblique impact loading. (C) 2018 Elsevier Ltd. All rights reserved.