Computational & Technology Resources
an online resource for computational,
engineering & technology publications
Civil-Comp Proceedings
ISSN 1759-3433
CCP: 100
Edited by: B.H.V. Topping
Paper 86

Mechano-Chemo-Electrical Finite Element Modelling of the Sensing Behaviour of Ionic Polymer Metal Composites

B. Akle1, W. Habchi1 and T. Wallmersperger2

1Department of Industrial and Mechanical Engineering, Lebanese American University, Byblos, Lebanon
2Institut für Festkörpermechanik, Technische Universität Dresden, Germany

Full Bibliographic Reference for this paper
B. Akle, W. Habchi, T. Wallmersperger, "Mechano-Chemo-Electrical Finite Element Modelling of the Sensing Behaviour of Ionic Polymer Metal Composites", in B.H.V. Topping, (Editor), "Proceedings of the Eighth International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 86, 2012. doi:10.4203/ccp.100.86
Keywords: smart materials, electro-active polymers, sensor, finite elements, ionic polymer metal composite, multiphysical modeling.

Ionic polymer metal composite (IMPC) is an electro-active polymer (EAP) that exhibits both electro-mechanical and mechano-electrical coupling. As an actuator IPMC exhibits bending strains up to 5% as a result of a 2V applied electrical potential across its electrodes. This smart material also generates electrical charges when it is mechanically deformed, and this behaviour makes it useful as a velocity sensor. In an earlier work by the authors [1,2] a numerical model was developed that is capable of simulating its actuation behaviour. The electro-chemical model is based on the Nernst-Planck and the Poisson's equations, while the chemo-mechanical model is based on experimental results demonstrating that the mechanical strain in IPTs is proportional to a linear term and a quadratic term of the charge accumulated at the electrode. In this study the same electro-chemical physics is employed to develop the sensing model. The chemo-mechanical component of the model is based on the fact that the negative anions in the IPMC are covalently attached to the polymer while the positive cations are free to move. Upon bending the actuator the anions concentration increases at the inner compressed side of the sensor while the concentration will decrease at the outer stretched side. Initially the cations are assumed to be immobile and then will move in the domain to maintain charge neutrality. In this paper the model is numerically simulated using the finite element method in a fully-coupled framework. The resulting nonlinear system of equations is solved by means of a damped Newton method [3]. The mesh is calibrated and the numerical results are verified with the literature. An experimental study is performed, in which the signal conditioning circuit is changed from an open circuit voltage sensing to short circuit charge and current sensing. Also the cation species of the IPMC sensor are changed from H+ to Na+ and later to Li+. The cation change is simulated with a change in the permittivity and mobility parameters, while the different signal conditioning circuits are considered by changes in the electrical boundary conditions. All these experimental results are compared to the numerical simulation with a good agreement in the trends.

B. Akle, W. Habchi, T. Wallmersperger, E. Akle, D. Leo, "High surface area electrodes in ionic polymer transducers: numerical and experimental investigations of the electro-chemical behavior", Journal of Applied Physics, 109, 074509, 2011. doi:10.1063/1.3556751
B. Akle, W. Habchi, T. Wallmersperger, D. Leo, "Finite element modeling of the electromechanical coupling in ionic polymer transducers", Proceedings of the SPIE Smart Structures NDE 2010, San Diego, USA, 2010. doi:10.1117/12.848781
P. Deuflhard, "Newton Methods for Nonlinear Problems, Affine Invariance and Adaptive Algorithms", Springer, Germany, 2004.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £50 +P&P)