Experimental Analysis of the Energy Absorption Properties of Foam-Filled Sunflower-Inspired Honeycomb Structures Combined with Re-Entrant Geometry under Out-of-Plane Quasi-Static Loading

Sarkhosh, Reza; Kazemi Nasrabadi, Mohammad; Zandieh, Mahdi

Experimental Analysis of the Energy Absorption Properties of Foam-Filled Sunflower-Inspired Honeycomb Structures Combined with Re-Entrant Geometry under Out-of-Plane Quasi-Static Loading

Document Type : Original Article

Authors

Reza Sarkhosh ¹

Mohammad Kazemi Nasrabadi ²

Mahdi Zandieh ³

¹ Assistant Professor, Department of Aerospace Engineering, Shahid Sattari University of Aeronautical Sciences and Technology, Tehran, Iran

² Associated Professor, Department of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran, Iran

³ MSC Student in Aerospace, Graduate Center, Shahid Sattari University of Aeronautical Sciences and Technology, Tehran,Iran

Abstract

Introduction: Bio-inspired cellular structures and auxetic geometries have attracted considerable attention due to their superior energy absorption capabilities and deformation characteristics. However, the combined effects of sunflower-inspired radial arrangement, re-entrant geometry, and foam filling on the mechanical response and energy absorption performance of cellular structures remain largely unexplored.
Methods: This study experimentally investigates the quasi-static compressive behavior of conventional honeycomb, sunflower-inspired, and hybrid sunflower re-entrant lattice structures in both hollow and polyurethane foam-filled configurations. The specimens were fabricated using three-dimensional (3D) printing technology with polylactic acid (PLA) material and tested under quasi-static compression.
Findings: The results demonstrated that cellular geometry significantly influences the buckling mechanism, deformation stability, and energy absorption capacity. The hybrid sunflower re-entrant structure exhibited a more uniform stress distribution and a more progressive collapse mode than the conventional honeycomb structure due to its auxetic behavior and radial–spiral arrangement. Furthermore, polyurethane foam increased the initial stiffness, delayed the onset of buckling, and improved the progressive crushing behavior. The proposed structure achieved a 112% increase in energy absorption, a 6% improvement in specific energy absorption, and a 3% enhancement in crushing force efficiency compared with the conventional honeycomb structure.
Conclusion:
The synergistic combination of sunflower-inspired geometry, re-entrant auxetic configuration, and polyurethane foam filling considerably enhances the energy absorption performance and deformation stability of cellular structures, indicating significant potential for applications in aerospace, automotive, and sandwich panel systems.

Keywords

Honeycomb structure

energy absorber

3D printer

sunflower

re-entrant structure

Quasi-Static Loading

20.1001.1.28211553.1405.5.1.1.6

Subjects

Maintenance and repair of the engine, wing and body of unmanned aerial vehicles/technology/construction/...

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