Design principles of energy absorbing structures subjected to combined shear-compression loading

Abstract

To maintain the robustness of crashworthiness performance in energy absorbing structures, high specific energy absorption (SEA) and crush force efficiency (CFE) need to be maintained across a wide range of load angles. In this paper, concave design was proposed to address this issue. Finite element analysis was utilised to identify the main load-bearing elements for axial and shear loading. Furthermore, the design concepts were classified into surface variation and cross-section variation. Pattern design, which is a representative design of surface variation, can enhance crashworthiness performance by reducing the initial crushing load and maximising the development of a travelling hinge. However, there is a drawback that designing the cross-section to maximise the development of the travelling hinge leads to an increase in the dihedral angle, resulting in a decrease in the CFE. This paper proposed the concave design, that ensures excellent robustness of crashworthiness performance and minimised the trade-off between SEA and CFE performance under combined shear-compression loading. The design induces local crushing due to geometric imperfections, which reduces the peak load while maintaining the high load-bearing capacity, thereby increasing SEA. Furthermore, the surface of the energy absorbing structure is an important load-bearing component that supports shear loads, and the concave design induces progressive crushing modes for any load angle, thereby maximising the deformation of the surface and improving SEA. The structural characteristics of the concave design were validated through quasi-static loading tests.

Keywords:

• combined shear-compression loading
• crashworthiness
• concave design
• finite element analysis

Acknowledgement

We thank ANSYS Korea for technical support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the Challengeable Future Defense Technology Research and Development Program (No.912766601) of Agency for Defense Development in 2023.