Multi-objective crashworthiness optimization for an auxetic cylindrical structure under axial impact loading

Publication date: 5 April 2018
Source:Materials & Design, Volume 143
Author(s): Qiang Gao, Xuan Zhao, Chenzhi Wang, Liangmo Wang, Zhengdong Ma
There is an increasing interest in designing lightweight automobile parts to enhance the passive safety of automobiles and reduce the fuel cost consumption. Variable kinds of novel smart structures/materials have been studied to apply in the field of the crashworthiness of the automobile. In this paper, a novel crash box based on the cylindrical cellular structure with negative Poisson's ratio (NPR) is proposed. The unit cell for the NPR structure is the double-V configuration. The structure can contract in the radial direction when compressed to enhance the stiffness. Then the parametric finite element (FE) model is constructed with MATLAB scripts to study the influence of the geometrical parameters on the crashworthiness. During the analysis, the Rescaled Range Analysis (RRA) is utilized. Then the specific energy absorption (SEA) and peak crushing force (PCF) are chosen as the optimization objective, and the Pareto fronts are attained by employing the multi-objective particle swarm optimization (MOPSO) algorithm. Also, the optimal results are compared with the initial model to verify the effectiveness of the approach. It is found that the SEA increases from 4.33KJ/Kg to 6.06KJ/kg by 39.3% and PCF decreases to 78.89KN by 10.3% when the geometry parameters are optimized. Compared with the thin-walled circle structure, the cylindrical NPR structure has lower peak crushing force and higher energy absorption. Also, the crushing force is more stable under the impact loading. Therefore, the cylindrical NPR structure has a great prospect in the application of the energy absorber of the automobile.

Graphical abstract

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