Energy absorption of origami tubes with polygonal cross-sections

Thin-walled tubes are widely used as energy absorption devices in transport vehicles. In this paper, with the goal of improving the energy absorption performance of tubes under quasi-static axial loading, origami tubes with polygonal cross-sections are designed. The geometric characteristics of polygonal origami tubes are controlled by three parameters: the number of sides, the number of modules and the dihedral angle. To investigate the effect of the origami pattern and polygonal structure on the crashworthiness of tubes, a full factorial experiment is adopted, and then parametric analysis is conducted based on eighty-five simulations. The numerical results validate that origami tubes collapsing in the complete diamond mode perform better than conventional tubes. However, this special mode can only be triggered in the crushing process of square and hexagonal origami tubes with smaller dihedral angles. The optimal design leads to a maximum reduction in the initial peak crushing force of 56.96% and a maximum increase in the mean crushing force of 45.49%. The parametric study shows that the initial peak crushing force of tubes with an identical number of modules and edges increases with an increasing dihedral angle, while it decreases with an increasing number of modules when the angle remains the same. Additionally, the influence of geometric parameters on the mean crushing force varies with different collapse modes. Furthermore, a deep insight into the in-extensible deformation mechanism of origami tubes deformed in the complete diamond mode is presented. The theoretical model is subsequently proposed to predict the mean crushing force.