Parametric Study of Truncated Square Pyramid Folded Structure for Effective Energy Absorption under Static and Dynamic Crushing

Abstract

The truncated square pyramid (TSP) folded structure was proposed recently, and its advantages such as easy fabrication, superior energy-absorption capacity, and better impact performance than many other types of core structures have been demonstrated by laboratory tests and numerical simulations. In this paper, a parametric study was conducted to investigate the effects of geometric parameters on the energy-absorption capacity of a TSP unit cell under both quasi-static and dynamic crushing. A novel re-entrant TSP unit cell is proposed by introducing the re-entrant edge at its corner to improve the performance of the originally proposed TSP. The numerical model of TSP unit cell was constructed and validated against the reconstructed TSP structure, and the results matched well. TSP unit cells with different geometric configurations were constructed by varying the open-top edge length b, the corner opening angle φ, and the re-entrant edge z. The structural response and damage mode of TSP unit cells with different geometric configurations were analyzed. Criteria such as the peak crushing force, average crushing force, uniformity ratio, and energy absorption were compared and used to evaluate the performance of the structure. The TSP unit cells with better performance in terms of energy absorption were selected to investigate further the influences of crushing speeds on their performance. It was found that the corner opening angle φ of a TSP unit cell has a greater influence on its energy absorption than other geometric parameters. Furthermore, the addition of re-entrant edge at the corner of a TSP unit cell effectively can reduce the peak crushing force, and results in a more uniform crushing process. Lastly, the peak crushing force is affected significantly by the crushing speed when the TSP unit cell has a large edge length b, whereas unit cells with small open-top length are less affected. The results provide guidance for the design of a TSP unit cell for high energy absorption against dynamic loads.