Pre-Assessment of Transtibial Prosthetic Pylon Using Auxetic Bowtie Model: A Simulation and Experimental Validation
Received: 21 August 2025 | Revised: 11 September 2025 and 17 September 2025 | Accepted: 20 September 2025 | Online: 29 January 2026
Corresponding author: Ubaidillah
Abstract
In the present study, a prosthetic device is designed to function as a replacement for a missing limb. This device typically consists of suspension, liner, socket, pylon, and foot components. The research objectives are to design a pylon component for transtibial prosthetics by implementing auxetic metamaterials and to validate the performance of the designed pylon under quasi-static and dynamic conditions. The design and analysis processes were conducted with Finite Element Analysis (FEA), and its effectiveness was validated through experimental testing of the prototype pylon sample. In the design process, the pylon structure is formulated by rearranging the Two-Dimensional (2D) re-entrant hexagon model into a Three-Dimensional (3D) model. The design evaluation identified that the pylon exhibits a stiffness of 1404 kN/mm, 4680 kN/mm, and 9360 kN/mm for the 0.3 mm, 1 mm, and 2 mm thick ligaments, respectively. It was found that a pylon with a 0.3 mm-thick ligament caused a deformation (S) of 0.53 cm during a single period of the gait cycle, while a 1 mm-thick ligament caused an S of 0.4 cm. It was also found from the S transition of the primary and secondary bends that a negative Poisson’s ratio occurred in the 3D model transformed from a 2D re-entrant hexagon.
Keywords:
transtibial prosthetics, auxetic metamaterials, pylon structure, ligament thickness, gait motionDownloads
References
C. Cipriani, M. Controzzi, and M. C. Carrozza, "Progress towards the development of the SmartHand transradial prosthesis," 2009 IEEE International Conference on Rehabilitation Robotics, 2009. DOI: https://doi.org/10.1109/ICORR.2009.5209620
H. M. Herr and A. M. Grabowski, "Bionic ankle-foot prosthesis normalizes walking gait for persons with leg amputation," Proceedings. Biological Sciences, vol. 279, no. 1728, pp. 457–464, Feb. 2012. DOI: https://doi.org/10.1098/rspb.2011.1194
S. A. A. Aziz, Ubaidillah, S. A. Mazlan, N. I. N. Ismail, and S.-B. Choi, "Implementation of functionalized multiwall carbon nanotubes on magnetorheological elastomer," Journal of Materials Science, vol. 53, no. 14, pp. 10122–10134, July 2018. DOI: https://doi.org/10.1007/s10853-018-2315-3
A. Z. B. Pokaad, K. Hudha, and M. Z. B. M. Nasir, "Simulation and experimental studies on the behaviour of a magnetorheological damper under impact loading," International Journal of Structural Engineering, vol. 2, no. 2, pp. 164–187, Jan. 2011. DOI: https://doi.org/10.1504/IJSTRUCTE.2011.039422
F. Imaduddin, S. A. Mazlan, Ubaidillah, H. Zamzuri, and A. Y. A. Fatah, "Testing and parametric modeling of magnetorheological valve with meandering flow path," Nonlinear Dynamics, vol. 85, no. 1, pp. 287–302, July 2016. DOI: https://doi.org/10.1007/s11071-016-2684-6
J. A. Maun, S. A. Gard, M. J. Major, and K. Z. Takahashi, "Reducing stiffness of shock-absorbing pylon amplifies prosthesis energy loss and redistributes joint mechanical work during walking," Journal of Neuroengineering and Rehabilitation, vol. 18, no. 1, Sept. 2021, Art. no. 143. DOI: https://doi.org/10.1186/s12984-021-00939-8
M. R. Ismail, Y. Y. Kahtan, and S. M. Abbas, "A modified shank for below knee prosthesis," IOP Conference Series: Materials Science and Engineering, vol. 671, no. 1, Jan. 2020, Art. no. 012061. DOI: https://doi.org/10.1088/1757-899X/671/1/012061
H. S. Hasan, S. M. Abbas, S. K. Mohammed, and M. Q. Ibraheem, "Modeling and Manufacturing of a Flexible Socket for Above-Knee Amputation Prosthesis," Engineering, Technology & Applied Science Research, vol. 15, no. 2, pp. 21257–21262, Apr. 2025. DOI: https://doi.org/10.48084/etasr.10046
C. W. Radcliffe, "Four-bar linkage prosthetic knee mechanisms: Kinematics, alignment and prescription criteria," Prosthetics and Orthotics International, vol. 18, no. 3, pp. 159–173, Dec. 1994. DOI: https://doi.org/10.3109/03093649409164401
H. Houdijk, D. Wezenberg, L. Hak, and A. G. Cutti, "Energy storing and return prosthetic feet improve step length symmetry while preserving margins of stability in persons with transtibial amputation," Journal of Neuroengineering and Rehabilitation, vol. 15, no. Suppl 1, Sept. 2018, Art. no. 76. DOI: https://doi.org/10.1186/s12984-018-0404-9
M. Kowalczyk and H. Jopek, "Numerical Analysis of the Lower Limb Prosthesis Subjected to Various Load Conditions," Vibrations in Physical Systems, vol. 31, 2020, Art. no. 20203091.
M. F. Fardan, B. W. Lenggana, U. Ubaidillah, S.-B. Choi, D. D. Susilo, and S. Z. Khan, "Revolutionizing Prosthetic Design with Auxetic Metamaterials and Structures: A Review of Mechanical Properties and Limitations," Micromachines, vol. 14, no. 6, June 2023, Art. no. 1165. DOI: https://doi.org/10.3390/mi14061165
C. Lees, J. F. V. Vincent, and J. E. Hillerton, "Poisson’s Ratio in Skin," Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 19–23, Feb. 1991. DOI: https://doi.org/10.3233/BME-1991-1104
J. B. Pendry, "Negative Refraction Makes a Perfect Lens," Physical Review Letters, vol. 85, no. 18, pp. 3966–3969, Oct. 2000. DOI: https://doi.org/10.1103/PhysRevLett.85.3966
J. B. Pendry, A. J. Holden, W. J. Stewart, and I. Youngs, "Extremely Low Frequency Plasmons in Metallic Mesostructures," Physical Review Letters, vol. 76, no. 25, pp. 4773–4776, June 1996. DOI: https://doi.org/10.1103/PhysRevLett.76.4773
S. Narayana and Y. Sato, "Heat Flux Manipulation with Engineered Thermal Materials," Physical Review Letters, vol. 108, no. 21, May 2012, Art. no. 214303. DOI: https://doi.org/10.1103/PhysRevLett.108.214303
Z. Liu et al., "Locally Resonant Sonic Materials," Science, vol. 289, no. 5485, pp. 1734–1736, Sept. 2000. DOI: https://doi.org/10.1126/science.289.5485.1734
Mechanics of Materials. USA: McGraw-Hill, 2013.
R. Lakes, "Foam Structures with a Negative Poisson’s Ratio," Science, vol. 235, no. 4792, pp. 1038–1040, Feb. 1987. DOI: https://doi.org/10.1126/science.235.4792.1038
C. Qi, A. Remennikov, L.-Z. Pei, S. Yang, Z.-H. Yu, and T. D. Ngo, "Impact and close-in blast response of auxetic honeycomb-cored sandwich panels: Experimental tests and numerical simulations," Composite Structures, vol. 180, pp. 161–178, Nov. 2017. DOI: https://doi.org/10.1016/j.compstruct.2017.08.020
A. G. Mark, S. Palagi, T. Qiu, and P. Fischer, "Auxetic metamaterial simplifies soft robot design: 2016 IEEE International Conference on Robotics and Automation, ICRA 2016," 2016 IEEE International Conference on Robotics and Automation, ICRA 2016, pp. 4951–4956, June 2016. DOI: https://doi.org/10.1109/ICRA.2016.7487701
H.-S. Kim, H.-J. Um, W. Hong, H.-S. Kim, and P. Hur, "Structural design for energy absorption during heel strike using the auxetic structure in the heel part of the prosthetic foot," in 2021 18th International Conference on Ubiquitous Robots (UR), July 2021, pp. 130–133. DOI: https://doi.org/10.1109/UR52253.2021.9494652
H. Yang, B. Wang, and L. Ma, "Mechanical properties of 3D double-U auxetic structures," International Journal of Solids and Structures, vol. 180–181, pp. 13–29, Dec. 2019. DOI: https://doi.org/10.1016/j.ijsolstr.2019.07.007
X. Li, Q. Wang, Z. Yang, and Z. Lu, "Novel auxetic structures with enhanced mechanical properties," Extreme Mechanics Letters, vol. 27, pp. 59–65, Feb. 2019. DOI: https://doi.org/10.1016/j.eml.2019.01.002
M. Bodaghi, A. Serjouei, A. Zolfagharian, M. Fotouhi, H. Rahman, and D. Durand, "Reversible energy absorbing meta-sandwiches by FDM 4D printing," International Journal of Mechanical Sciences, vol. 173, May 2020, Art. no. 105451. DOI: https://doi.org/10.1016/j.ijmecsci.2020.105451
W. Yang, R. Huang, J. Liu, J. Liu, and W. Huang, "Ballistic impact responses and failure mechanism of composite double-arrow auxetic structure," Thin-Walled Structures, vol. 174, May 2022, Art. no. 109087. DOI: https://doi.org/10.1016/j.tws.2022.109087
H.-J. Um, H.-S. Kim, W. Hong, H.-S. Kim, and P. Hur, "Design of 3D printable prosthetic foot to implement nonlinear stiffness behavior of human toe joint based on finite element analysis," Scientific Reports, vol. 11, no. 1, Oct. 2021, Art. no. 19780. DOI: https://doi.org/10.1038/s41598-021-98839-3
M. J. Mirzaali, S. Janbaz, M. Strano, L. Vergani, and A. A. Zadpoor, "Shape-matching soft mechanical metamaterials," Scientific Reports, vol. 8, no. 1, Jan. 2018, Art. no. 965. DOI: https://doi.org/10.1038/s41598-018-19381-3
M. H. Zamani, M. Heidari-Rarani, and K. Torabi, "Optimal design of a novel graded auxetic honeycomb core for sandwich beams under bending using digital image correlation (DIC)," Composite Structures, vol. 286, Apr. 2022, Art. no. 115310. DOI: https://doi.org/10.1016/j.compstruct.2022.115310
L. Yang, O. Harrysson, H. West, and D. Cormier, "Mechanical properties of 3D re-entrant honeycomb auxetic structures realized via additive manufacturing," International Journal of Solids and Structures, vol. 69–70, pp. 475–490, Sept. 2015. DOI: https://doi.org/10.1016/j.ijsolstr.2015.05.005
J. M. Reverte, M. Á. Caminero, J. M. Chacón, E. García-Plaza, P. J. Núñez, and J. P. Becar, "Mechanical and Geometric Performance of PLA-Based Polymer Composites Processed by the Fused Filament Fabrication Additive Manufacturing Technique," Materials, vol. 13, no. 8, Jan. 2020, Art. no. 1924. DOI: https://doi.org/10.3390/ma13081924
ASTM E8/E8M-22 Standard Test Methods for Tension Testing of Metallic Materials. USA: ASTM International, 2024.
H. Hazimi, U. Ubaidillah, R. Alnursyah, H. Nursya’bani, B. W. Lenggana, and Wibowo, "Improvement of Space Tube Frame for Formula Student Vehicle," in Proceedings of the 6th International Conference and Exhibition on Sustainable Energy and Advanced Materials, Singapore, 2020, pp. 735–744. DOI: https://doi.org/10.1007/978-981-15-4481-1_70
S. A. Gard and R. J. Konz, "The effect of a shock-absorbing pylon on the gait of persons with unilateral transtibial amputation," Journal of Rehabilitation Research and Developmen, vol. 40, no. 2, pp. 111–126, 2003. DOI: https://doi.org/10.1682/JRRD.2003.03.0111
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Copyright (c) 2026 Bhre Wangsa Lenggana, Muhammad Faris Fardan, Ubaidillah, Seung-Bok Choi, Didik Djoko Susilo, Sohaib Zia Khan, Asad Ali Zaidi
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