Semnan University Press Mechanics of Advanced Composite Structures 2423-4826 14 2 2027 11 01 Reduction of Biaxial Bending and Torsion in Ionic Polymer-Metal Actuators through Symmetric Voltage Distribution and Improved Boundary Conditions 369 382 10518 10.22075/macs.2026.38454.1894 EN Reza Poureini Department of Mechanical Engineering, SR.C., Islamic Azad University, Tehran, 1477893855, Iran 0009-0009-5287-8070 Hamid Soleimanimehr Department of Mechanical Engineering, SR.C., Islamic Azad University, Tehran, 1477893855, Iran Modern Automotive Research Center, SR.C., Islamic Azad University, Tehran, 1477893855, Iran 0000-0001-8931-5698 Navid Viliani Department of Mechanical Engineering, Ab.C., Islamic Azad University, Abhar, 4561934367, Iran Ali Abdollahi Department of Mechanical Engineering, SR.C., Islamic Azad University, Tehran, 1477893855, Iran Journal Article 2025 07 26 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. https://macs.semnan.ac.ir/article_10518_2d86c49db27011beb778b65b84d15017.pdf