Modelling the Deformation of Polydomain Liquid Crystal Elastomers as a State of Hyperelasticity

Mokarram Hossain1, Zhengxuan Wei2, Ruobing Bai2
1Cardiovascular Engineering Research Lab (CERL), School of Mechanical and Design Engineering, University of Portsmouth, Anglesea Road, Portsmouth PO1 3DJ, UK
2Department of Mechanical and Industrial Engineering, College of Engineering, Northeastern University, Boston, Massachusetts, 02115, USA

Tóm tắt

Abstract

A hyperelasticity modelling approach is employed for capturing various and complex mechanical behaviours exhibited by macroscopically isotropic polydomain liquid crystal elastomers (LCEs). These include the highly non-linear behaviour of nematic-genesis polydomain LCEs, and the soft elasticity plateau in isotropic-genesis polydomain LCEs, under finite multimodal deformations (uniaxial and pure shear) using in-house synthesised acrylate-based LCE samples. Examples of application to capturing continuous softening (i.e., in the primary loading path), discontinuous softening (i.e., in the unloading path) and auxetic behaviours are also demonstrated on using extant datasets. It is shown that our comparatively simple model, which breaks away from the neo-classical theory of liquid crystal elastomers, captures the foregoing behaviours favourably, simply as states of hyperelasticity. Improved modelling results obtained by our approach compared with the existing models are also discussed. Given the success of the considered model in application to these datasets and deformations, the simplicity of its functional form (and thereby its implementation), and comparatively low(er) number of parameters, the presented isotropic hyperelastic strain energy function here is suggested for: (i) modelling the general mechanical behaviour of LCEs, (ii) the backbone in the neo-classical theory, and/or (iii) the basic hyperelastic model in other frameworks where the incorporation of the director, anisotropy, viscoelasticity, temperature, softening etc parameters may be required.

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Tài liệu tham khảo

Traugutt, N.A., Volpe, R.H., Bollinger, M.S., Saed, M.O., Torbati, A.H., Yu, K., Dadivanyan, N., Yakacki, C.M.: Liquid-crystal order during synthesis affects main-chain liquid-crystal elastomer behaviour. Soft Matter 13, 7013–7025 (2017). https://doi.org/10.1039/C7SM01405H

Biggins, J.S., Warner, M., Bhattacharya, K.: Elasticity of polydomain liquid crystal elastomers. J. Mech. Phys. Solids 60, 573–590 (2012). https://doi.org/10.1016/j.jmps.2012.01.008

Wei, Z., Wang, P., Bai, R.: Thermomechanical coupling in polydomain liquid crystal elastomers. J. Appl. Mech. 91, 021001 (2024). https://doi.org/10.1115/1.4063219

Tokumoto, H., Zhou, H., Takebe, A., Kamitani, K., Kojio, K., Takahara, A., Bhattacharya, K., Urayama, K.: Probing the in-plane liquid-like behavior of liquid crystal elastomers. Sci. Adv. 7, eabe9495 (2021). https://doi.org/10.1126/sciadv.abe9495

Lee, V., Bhattacharya, K.: Universal deformations of incompressible nonlinear elasticity as applied to ideal liquid crystal elastomers. J. Elast. (2023). https://doi.org/10.1007/s10659-023-10018-9

Urayama, K., Kohmon, E., Kojima, M., Takigawa, T.: Polydomain – monodomain transition of randomly disordered nematic elastomers with different cross-linking histories. Macromolecules 42, 4084–4089 (2009). https://doi.org/10.1021/ma9004692

Biggins, J.S., Warner, M., Bhattacharya, K.: Supersoft elasticity in polydomain nematic elastomers. Phys. Rev. Lett. 103, 037802 (2010). https://doi.org/10.1103/PhysRevLett.103.037802

Mistry, D., Morgan, P.B., Clamp, J.H., Gleeson, H.F.: New insights into the nature of semi-soft elasticity and “mechanical-Fréedericksz transitions” in liquid crystal elastomers. Soft Matter 14, 1301–1310 (2018). https://doi.org/10.1039/C7SM02107K

Mistry, D., Connel, S.D., Mickthwaite, S.L., Morgan, P.B., Clamp, J.H., Gleeson, H.F.: Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer. Nat. Commun. 9, 5095 (2018). https://doi.org/10.1038/s41467-018-07587-y

Raistrick, T., Zhang, Z., Mistry, D., Mattsson, J., Gleeson, H.F.: Understanding the physics of the auxetic response in a liquid crystal elastomer. Phys. Rev. Res. 3, 023191 (2021). https://doi.org/10.1103/PhysRevResearch.3.023191

Merkel, D.R., Shaha, R.K., Yakacki, C.M., Frick, C.P.: Mechanical energy dissipation in polydomain nematic liquid crystal elastomers in response to oscillating loads. Polymer 166, 148–154 (2019). https://doi.org/10.1016/j.polymer.2019.01.042

Warner, M., Gelling, K.P., Vilgis, T.A.: Theory of nematic networks. J. Chem. Phys. 88, 4008–4013 (1988). https://doi.org/10.1063/1.453852

Warner, M., Wang, X.J.: Elasticity and phase behavior of nematic elastomers. Macromolecules 24, 4932–4941 (1991). https://doi.org/10.1021/ma00017a033

Bladon, P., Terentjev, E.M., Warner, M.: Transitions and instabilities in liquid crystal elastomers. Phys. Rev. E 47, R3838–R3840 (1993). https://doi.org/10.1103/PhysRevE.47.R3838

Bladon, P., Terentjev, E.M., Warner, M.: Deformation-induced orientational transitions in liquid crystal elastomers. J. Phys. II 4, 75–91 (1994). https://doi.org/10.1051/jp2:1994100

DeSimone, A., Teresi, L.: Elastic energies for nematic elastomers. Eur. Phys. J. E 29, 191–204 (2009). https://doi.org/10.1140/epje/i2009-10467-9

Agostiniani, V., DeSimonel, A.: Ogden-type energies for nematic elastomers. Int. J. Non-Linear Mech. 47, 402–412 (2012). https://doi.org/10.1016/j.ijnonlinmec.2011.10.001

Anssari-Benam, A., Horgan, C.O.: On modelling simple shear for isotropic incompressible rubber-like materials. J. Elast. 147, 83–111 (2021). https://doi.org/10.1007/s10659-021-09869-x

Anssari-Benam, A., Destrade, M., Saccomandi, G.: Modelling brain tissue elasticity with the Ogden model and an alternative family of constitutive models. Philos. Trans. R. Soc. Lond. Ser. A 380, 20210325 (2022). https://doi.org/10.1098/rsta.2021.0325

Anssari-Benam, A.: Comparative modelling results between a separable and a non-separable form of principal stretches–based strain energy functions for a variety of isotropic incompressible soft solids: Ogden model compared with a parent model. Mech. Soft Mater. 5, 2 (2023). https://doi.org/10.1007/s42558-023-00050-z

Fried, E., Sellers, S.: Soft elasticity is not necessary for striping in nematic elastomers. J. Appl. Phys. 100, 043521 (2006). https://doi.org/10.1063/1.2234824

Mihai, L.A., Goriely, A.: A pseudo-anelastic model for stress softening in liquid crystal elastomers. Proc. R. Soc. A 476, 20200558 (2020). https://doi.org/10.1098/rspa.2020.0558

Mihai, L.A., Mistry, D., Raistrick, T., Gleeson, H.F., Goriely, A.: A mathematical model for the auxetic response of liquid crystal elastomers. Philos. Trans. R. Soc. Lond. Ser. A 380, 20210326 (2022). https://doi.org/10.1098/rsta.2021.0326

Anssari-Benam, A.: Continuous softening up to the onset of failure: a hyperelastic modelling approach with intrinsic softening for isotropic incompressible soft solids. Mech. Res. Commun. 132, 104183 (2023). https://doi.org/10.1016/j.mechrescom.2023.104183

He, Q., Zheng, Y., Wang, Z., He, X., Cai, S.: Anomalous inflation of a nematic balloon. J. Mech. Phys. Solids 142, 104013 (2020). https://doi.org/10.1016/j.jmps.2020.104013

Ogden, R.W., Roxburgh, D.G.: A pseudo–elastic model for the Mullins effect in filled rubbe. Proc. R. Soc. Lond. A 455, 2861–2877 (1999). https://doi.org/10.1098/rspa.1999.0431

Anssari-Benam, A., Akbari, R., Dargazany, R.: Extending the theory of pseudo-elasticity to capture the permanent set and the induced anisotropy in the Mullins effect. Int. J. Non-Linear Mech. 156, 104500 (2023). https://doi.org/10.1016/j.ijnonlinmec.2023.104500

Anssari-Benam, A.: A generalised $W\left (I_{1},I_{2}\right )$ strain energy function of binomial form with unified applicability across various isotropic incompressible soft solids. Acta Mech. 235, 99–132 (2024). https://doi.org/10.1007/s00707-023-03677-1

Anssari-Benam, A.: On a new class of non-Gaussian molecular based constitutive models with limiting chain extensibility for incompressible rubber-like materials. Math. Mech. Solids 26, 1660–1674 (2021). https://doi.org/10.1177/10812865211001094

Carroll, M.M.: A strain energy function for vulcanized rubbers. J. Elast. 103, 173–187 (2011). https://doi.org/10.1007/s10659-010-9279-0

Mihai, L.A., Goriely, A.: Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials. Proc. R. Soc. Lond. A 467, 3633–3646 (2011). https://doi.org/10.1098/rspa.2011.0281

Treloar, L.R.G.: The elasticity of a network of long-chain molecules - II. Trans. Faraday Soc. 39, 241–246 (1943). https://doi.org/10.1039/TF9433900241

Gent, A.N.: A new constitutive relation for rubber. Rubber Chem. Technol. 69, 59–61 (1996). https://doi.org/10.5254/1.3538357

Anssari-Benam, A., Horgan, C.O.: A three-parameter structurally motivated robust constitutive model for isotropic incompressible unfilled and filled rubber-like materials. Eur. J. Mech. A, Solids 95, 104605 (2022). https://doi.org/10.1016/j.euromechsol.2022.104605

Anssari-Benam, A., Bucchi, A.: Modelling the deformation of the elastin network in the aortic valve. J. Biomech. Eng. 140, 011004 (2018). https://doi.org/10.1115/1.4037916

Anssari-Benam, A., Bucchi, A.: A generalised neo-Hookean strain energy function for application to the finite deformation of elastomers. Int. J. Non-Linear Mech. 128, 103626 (2021). https://doi.org/10.1016/j.ijnonlinmec.2020.103626

Saed, M.O., Torbati, A.H., Nair, D.P., Yakacki, C.M.: Synthesis of programmable main-chain liquid-crystalline elastomers using a two-stage thiol-acrylate reaction. J. Vis. Exp. 107, 53546 (2016). https://doi.org/10.3791/53546

Traugutt, N.A., Volpe, R.H., Bollinger, M.S., Saed, M.O., Torbati, A.H., Yu, K., Dadivanyanc, N., Yakacki, C.M.: Liquid-crystal order during synthesis affects main-chain liquid-crystal elastomer behavior. Soft Matter 13, 7013–7025 (2017). https://doi.org/10.1039/C7SM01405H

Dorfmann, A., Ogden, R.W.: A constitutive model for the Mullins effect with permanent set in particle-reinforced rubber. Int. J. Solids Struct. 41, 1855–1878 (2004). https://doi.org/10.1016/j.ijsolstr.2003.11.014

Anssari-Benam, A.: Large isotropic elastic deformations: on a comprehensive model to correlate the theory and experiments for incompressible rubber-like materials. J. Elast. 153, 219–244 (2023). https://doi.org/10.1007/s10659-022-09982-5

Anssari-Benam, A., Hossain, M.: A pseudo-hyperelastic model incorporating the rate effects for isotropic rubber-like materials. J. Mech. Phys. Solids 179, 105347 (2023). https://doi.org/10.1016/j.jmps.2023.105347

Ogden, R.W.: Large deformation isotropic elasticity – on the correlation of theory and experiment for incompressible rubberlike solids. Proc. R. Soc. Lond. A 326, 565–584 (1972). https://doi.org/10.1098/rspa.1972.0026

Ciambella, J., Bezazi, A., Saccomandi, G., Scarpa, F.: Nonlinear elasticity of auxetic open cell foams modeled as continuum solids. J. Appl. Phys. 117, 184902 (2015). https://doi.org/10.1063/1.4921101