Mechanics of Advanced Composite Structures

Mechanics of Advanced Composite Structures

Reduction of Biaxial Bending and Torsion in Ionic Polymer-Metal Actuators through Symmetric Voltage Distribution and Improved Boundary Conditions

Document Type : Research Article

Authors
Reza Poureini 1
Hamid Soleimanimehr 1, 2
Navid Viliani 3
Ali Abdollahi 1
1 Department of Mechanical Engineering, SR.C., Islamic Azad University, Tehran, 1477893855, Iran
2 Modern Automotive Research Center, SR.C., Islamic Azad University, Tehran, 1477893855, Iran
3 Department of Mechanical Engineering, Ab.C., Islamic Azad University, Abhar, 4561934367, Iran
10.22075/macs.2026.38454.1894
Abstract
In this paper, a combined analytical and numerical framework is presented to reduce or eliminate biaxial bending and torsion in ionic polymer–metal composite (IPMC) actuators. The problem is formulated based on the coupled Nernst–Planck–Poisson model for ion transport and electric field distribution, together with the Euler–Bernoulli beam theory for mechanical response. The main innovation of this study is the integrated design of a two-dimensional symmetric electric field distribution V(x,y) and modified electrochemical–mechanical boundary conditions that simultaneously suppress transverse and torsional gradients. In addition, field- and time-dependent mechanical moduli E and G are introduced to represent viscoelastic effects and electro-mechanical softening more realistically. This comprehensive coupling allows the model to maintain both mathematical and physical symmetry, leading to a uniform ion distribution and balanced bending–torsion response—an advancement beyond previous electro-chemo-mechanical models that considered symmetry only partially or in a single direction. Numerical results, using realistic dimensions and a 5 V applied voltage, show that the proposed symmetric field design can reduce transverse bending by up to 87.5% and torsional strain energy by up to 88%. These findings demonstrate that optimized electric field design, appropriate boundary conditions, and field-dependent viscoelastic modeling can substantially enhance IPMC actuator performance and minimize undesired biaxial deformation.
Keywords
Ionic Polymer-Metal Composite
Energy Method
Nernst-Planck Equation
Biaxial Bending
Torsion
Subjects
[1]   Shahinpoor, M., Bar-Cohen, Y., Simpson, J.O. and Smith, J., 1998. Ionic polymer-metal composites (IPMCs) as biomimetic sensors, actuators, and artificial muscles-a review. Smart materials and structures, 7(6), p.R15.
[2]   Wang, C.M., Kitipornchai, S., Lim, C.W. and Eisenberger, M., 2008. Beam bending solutions based on nonlocal Timoshenko beam theory. Journal of Engineering Mechanics, 134(6), pp.475-481.
[3]   Zenkour, A. M., Arefi, M., & Alshehri, N. A., 2017. Size-dependent analysis of a sandwich curved nanobeam integrated with piezomagnetic face-sheets. Results in Physics, 7, pp. 2172–2182.
[4]   Arefi, M., & Zenkour, A. M., 2018. Thermal stress and deformation analysis of a size-dependent curved nanobeam based on sinusoidal shear deformation theory. Alexandria Engineering Journal, 57(3), pp. 2177–2185.
[5]   Arefi, M., & Zenkour, A. M., 2017. Analysis of wave propagation in a functionally graded nanobeam resting on visco-Pasternak’s foundation. Theoretical and Applied Mechanics Letters, 7(3), pp. 145–151.
[6]   Arshadi, K., & Arefi, M., 2023. Out-of-plane strain included formulation for free vibration and bending analyses of a sandwich GPL-reinforced microbeam based on the MCST. Journal of Vibration Engineering & Technologies, 11(5), pp. 2199–2214.
[7]   Arefi, M., Bidgoli, E. M. R., Dimitri, R., Bacciocchi, M., & Tornabene, F., 2019. Nonlocal bending analysis of curved nanobeams reinforced by graphene nanoplatelets. Composites Part B: Engineering, 166, pp. 1–12.
[8]   Soleimanimehr, H., Nasrollah, A. and Mosaddeghi, A.M., 2021. Numerical Solution of the Nernst-Planck Equation for Ionic Polymer Metal Composite Fixed- Fixed Beam. Advances in Robotics & Mechanical Engineering, 3, pp. 272-277.
[9]   Annabestani, M., Naghavi, N. and Maymandi-Nejad, M., 2021. A 3D analytical ion transport model for ionic polymer metal composite actuators in large bending deformations. Scientific reports, 11(1), p.6435.
[10] Buchberger, G. and Schoeftner, J., 2013. Modeling of slender laminated piezoelastic beams with resistive electrodes—comparison of analytical results with three-dimensional finite element calculations. Smart materials and structures, 22(3), p.032001.
[11] Boldini, A., 2024. A multi-cation model for the actuation of ionic membranes with ionic liquids. Materials Advances, 5(12), pp. 5213-5230.
[12] Saccardo, M.C., Barbosa, R., Zuquello, A.G., Blanco, G.E.D.O., Tozzi, K.A., Gonçalves, R. and Scuracchio, C.H., 2024. Beyond static: Tracking the dynamic nature of water absorption and Young's modulus in IPMC devices. Journal of Applied Polymer Science, 141(31), p.e55730.
[13] Mahmoodi, M.J. and Taghavi-Ganji, A., 2024. Nonlinear numerical analysis of actuation response of ionic polymer metal composite cantilever considering coupled electrical, chemical, and mechanical fields. Amirkabir Journal of Mechanical Engineering, 56(1), pp.125-146.
[14] Tao, H., Hu, G., Lu, S., Li, B., Zhang, Y. and Ru, J., 2024. Single-Walled Carbon Nanotube-Reinforced PEDOT: PSS Hybrid Electrodes for High-Performance Ionic Electroactive Polymer Actuator. Materials, 17(10), p.2469.
[15] Soleimanimehr, H. and Nasrollah, A., 2021. A numerical investigation the effects of the voltage on the displacement and stress of copper-based ionic polymer-metal composites. Journal of Modern Processes in Manufacturing and Production, 10(1), pp.77-86.
[16] Biswal, D.K. and Nayak, B., 2016. Analysis of time dependent bending response of Ag-IPMC actuator. Procedia Engineering, 144, pp.600-606.
[17] Boldini, A. and Porfiri, M., 2020. Multiaxial deformations of ionic polymer metal composites. International Journal of Engineering Science, 149, p.103227.
[18] Xu, B., Wang, S., Zhang, Z., Ling, J., & Wu, X., 2021. Improving the torsion performance of IPMC by changing the electrode separation. Scientific reports, 11(1), 7639.
[19] Sharif, M. A., Lei, H., Al-Rubaiai, M. K., & Tan, X., 2018. Ionic polymer-metal composite torsional sensor: physics-based modeling and experimental validation. Smart Materials and Structures, 27(7), 075039.
[20] Hu, N., Li, B., Bai, R., Xie, K., & Chen, G., 2023. A torsion-bending antagonistic bistable actuator enables untethered crawling and swimming of miniature robots. Research, 6, 0116.
[21] Lei, H., Sharif, M. A., & Tan, X., 2016. A dynamic physics-based model for tubular IPMC sensors under torsional excitation. In Electroactive Polymer Actuators and Devices (EAPAD) 2016, April (Vol. 9798, pp. 618-626). SPIE.
[22] Kim, K. J., Pugal, D., & Leang, K. K., 2011. A twistable ionic polymer-metal composite artificial muscle for marine applications. Marine Technology Society Journal, 45(4), pp. 83-98.
[23] Lee, J. H., Chee, P. S., Lim, E. H., Low, J. H., & Nguyen, N. T., 2022. A stretchable kirigami‐inspired self‐powered electroactive sensor for tensile strain and torsion sensing. Advanced Engineering Materials, 24(4), 2100961.
[24] López-Díaz, A., Vázquez, A.S. and Vázquez, E., 2024. Hydrogels in soft robotics: past, present, and future. ACS Nano, 18(32), pp.20817–20826.
[25] Dehkordi, H. R. B., Beni, Y. T., & Arvin, H., 2024. On the coupled bending–torsional analysis of flexoelectric microbeams. Archives of Civil and Mechanical Engineering, 25(1), 53.
[26] Balali Dehkordi, H. R., & Tadi Beni, Y., 2024. Size-dependent coupled bending-torsional analysis of piezoelectric microbeams. Mechanics Based Design of Structures and Machines, 52(9), pp. 6484–6506.
[27] Rao, S.S., 2019. Vibration of continuous systems. John Wiley & Sons.
[28] Ugural, A.C., 2009. Stresses in beams, plates, and shells. CRC press.
[29] Shahinpoor, M. ed., 2015. Ionic Polymer Metal Composites (IPMCs): Smart Multi-Functional Materials and Artificial Muscles, Volume 2. Royal Society of Chemistry.
[30] Popov, E.P., 1976. Mechanics of materials, Prentice-Hall.
[31] Tian, T., Zhai, Q. and Zhang, R., 2018. A new modified weak Galerkin finite element scheme for solving the stationary Stokes equations. Journal of Computational and Applied Mathematics, 329, pp.268–279.
[32] Nasrollah, A., Soleimanimehr, H. and Haghighi, S.B., 2024. IPMC-based actuators: An approach for measuring a linear form of its static equation. Heliyon, 10(4).
[33] Leo, D.J., 2007. Engineering analysis of smart material systems. John Wiley & Sons.
[34] Poureini, R., Soleimanimehr, H., Viliani, N. S., & Abdollahi, A., 2025. Investigation of the effect of a nonlinear ion concentration function on the electromechanical behavior of ionic polymer–metal composites. Journal of Modern Processes in Manufacturing and Production, 2(14), pp. 27–46.
Mechanics of Advanced Composite Structures
Volume 14, Issue 2 - Serial Number 30
In Progress
November 2027
Pages 369-382