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Low-Velocity Impact Response and Force Transmission in 2D Architected Sandwich Cores: Effect of Cell Angle and Functional Grading
Subject area: Science,Engineering and Technology · Area of research: Mechanical
Abstract
Architected sandwich cores intended for protective applications must be assessed on the force they transmit to a protected substrate, not only on the load they withstand. This study reports the low-velocity impact response of eight two-dimensional architected sandwich core configurations and evaluates them on transmitted force and damage containment. Honeycomb cores at unit-cell angles of 15°, 30° and 45°, diamond cores at 45°, 90° and 120°, and a functionally graded variant of each topology were additively manufactured from a UV-cured brittle photopolymer and each subjected to a single low-velocity impact from an 18 N steel sphere released from 300 mm, corresponding to a nominal incident energy of 5.4 J, with five replicate specimens per configuration. Transmitted force was recorded at a sensor beneath the panel and the fracture process was captured by high-speed imaging. Peak transmitted force varied by a factor of 3.2 across the configuration set, from 2447.08 ± 42.38 N for the 45° diamond core to 761.02 ± 27.30 N for the 120° diamond core. The two topologies behaved differently: all honeycomb configurations transmitted between 1698 and 1946 N and were insensitive to cell angle, whereas the diamond configurations spanned the full range and were strongly angle-dependent. The configurations transmitting the lowest force also fractured least, dissipating incident energy through large-scale compliant core deformation rather than through cracking, and exhibited correspondingly broader force-time profiles. Comparison against quasi-static data for the same configurations shows that the stiffness ranking established under static loading is preserved under impact, consistent with the Type I and Type II framework, but that the ranking by protective performance is inverted: the stiffest configuration is the poorest attenuator. Functional grading additionally confined damage to prescribed core regions while leaving stiffer regions intact. These results indicate that cell angle in the diamond topology functions as a single geometric parameter selecting between structural and protective performance regimes.
Keywords
architected materials; sandwich structures; low-velocity impact; force transmission; energy absorption; functionally graded lattices; high-speed imaging; additive manufacturing
References
[1] M. F. Ashby and Y. J. M. Bréchet, “Designing hybrid materials,” Acta Materialia, vol. 51, no. 19, pp. 5801–5821, 2003. ScienceDirect
[2] J. R. Greer and V. S. Deshpande, “Three-dimensional architected materials and structures: Design, fabrication, and mechanical behavior,” MRS Bulletin, vol. 44, no. 10, pp. 750–757, 2019. Cambridge
[3] C. R. Calladine and R. W. English, “Strain-rate and inertia effects in the collapse of two types of energy-absorbing structure,” International Journal of Mechanical Sciences, vol. 26, no. 11–12, pp. 689–701, 1984. ScienceDirect
[4] F. Zhu, G. Lu, D. Ruan, and Z. Wang, “Plastic Deformation, Failure and Energy Absorption of Sandwich Structures with Metallic Cellular Cores,” International Journal of Protective Structures, vol. 1, no. 4, pp. 507–541, 2010. SAGE
[5] H. Yazdani Sarvestani, A. H. Akbarzadeh, A. Mirbolghasemi, and K. Hermenean, “3D printed meta-sandwich structures: Failure mechanism, energy absorption and multi-hit capability,” Materials & Design, vol. 160, pp. 179–193, 2018. ScienceDirect
[6] S. Hou, T. Li, Z. Jia, and L. Wang, “Mechanical properties of sandwich composites with 3D-printed auxetic and non-auxetic lattice cores under low velocity impact,” Materials & Design, vol. 160, pp. 1305–1321, 2018. ScienceDirect
[7] H. Niknam and A. H. Akbarzadeh, “Graded lattice structures: Simultaneous enhancement in stiffness and energy absorption,” Materials & Design, vol. 196, p. 109129, 2020. ScienceDirect
[8] I. Maskery et al., “A mechanical property evaluation of graded density Al-Si10-Mg lattice structures manufactured by selective laser melting,” Materials Science and Engineering A, vol. 670, pp. 264–274, 2016. ScienceDirect
[9] B. Fadayomi, “Failure Modes and Fracture-Path Reproducibility in 2D Honeycomb and Diamond Sandwich Architected Cores Under Quasi-Static Loading,” companion manuscript, submitted concurrently.
How to cite this paper
@article{1722650,
author = {Bamidele Fadayomi},
title = {Low-Velocity Impact Response and Force Transmission in 2D Architected Sandwich Cores: Effect of Cell Angle and Functional Grading},
journal = {Iconic Research And Engineering Journals},
year = {2023},
volume = {6},
number = {11},
pages = {1078-1088},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1722650.pdf},
abstract = {Architected sandwich cores intended for protective applications must be assessed on the force they transmit to a protected substrate, not only on the load they withstand. This study reports the low-velocity impact response of eight two-dimensional architected sandwich core configurations and evaluates them on transmitted force and damage containment. Honeycomb cores at unit-cell angles of 15°, 30° and 45°, diamond cores at 45°, 90° and 120°, and a functionally graded variant of each topology were additively manufactured from a UV-cured brittle photopolymer and each subjected to a single low-velocity impact from an 18 N steel sphere released from 300 mm, corresponding to a nominal incident energy of 5.4 J, with five replicate specimens per configuration. Transmitted force was recorded at a sensor beneath the panel and the fracture process was captured by high-speed imaging. Peak transmitted force varied by a factor of 3.2 across the configuration set, from 2447.08 ± 42.38 N for the 45° diamond core to 761.02 ± 27.30 N for the 120° diamond core. The two topologies behaved differently: all honeycomb configurations transmitted between 1698 and 1946 N and were insensitive to cell angle, whereas the diamond configurations spanned the full range and were strongly angle-dependent. The configurations transmitting the lowest force also fractured least, dissipating incident energy through large-scale compliant core deformation rather than through cracking, and exhibited correspondingly broader force-time profiles. Comparison against quasi-static data for the same configurations shows that the stiffness ranking established under static loading is preserved under impact, consistent with the Type I and Type II framework, but that the ranking by protective performance is inverted: the stiffest configuration is the poorest attenuator. Functional grading additionally confined damage to prescribed core regions while leaving stiffer regions intact. These results indicate that cell angle in the diamond topology functions as a single geometric parameter selecting between structural and protective performance regimes.},
keywords = {architected materials; sandwich structures; low-velocity impact; force transmission; energy absorption; functionally graded lattices; high-speed imaging; additive manufacturing},
month = {May},
}