2606004103
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On the Evolution of Internal Variables for Anisotropic Viscoelastic Media

  • Armando Ciancio 1,   
  • Bruno Felice Filippo Flora 2,   
  • Vincenzo Ciancio 3,*

Received: 02 May 2026 | Revised: 03 Jun 2026 | Accepted: 25 Jun 2026 | Published: 14 Jul 2026

Abstract

The description of viscoelastic media with memory requires a thermodynamic formalism capable of capturing irreversible processes. In this work, a physicalmathematical model for anisotropic viscoelastic materials is developed based on the V. Ciancio—G.A. Kluitenberg theory. The generalized evolution equation is derived, showing its connection with modified Euler-Lagrange equations and the Rayleigh dissipation function. A direct and explicit reduction to the classical Maxwell model for viscoelasticity is demonstrated in the appropriate limit, confirming the consistency of the proposed framework. This work aims to offer a unified theoretical framework, providing a solid foundation for future developments.

References 

  • 1.

    Meixner, J. Zur Thermodynamik der irreversiblen Prozesse. Ann. Phys. 1943, 435, 244–270.

  • 2.

    Kluitenberg, G.A. Thermodynamical theory of elasticity and plasticity. Physica 1962, 28, 217–232.

  • 3.

    Kluitenberg, G.A. On the thermodynamics of viscosity and plasticity. Physica 1963, 29, 633–652.

  • 4.

    Kluitenberg, G.A.; Ciancio, V. On linear dynamical equations of state for isotropic media -I- General formalism. Physica 1978, 93, 273–286.

  • 5.

    Ciancio, V.; Kluitenberg, G.A. On linear dynamical equations of state for isotropic media -II- Some cases of special interest. Physica 1979, 99, 592–600.

  • 6.

    Ciancio, V. Propagation and attenuation of singular wave surfaces in linear inelastic media. Physica 1979, 97, 127–138.

  • 7.

    Kluitenberg, G.A. On vectorial internal variables and dielectric and magnetic relaxation phenomena. Physica 1981, 109, 91–122.

  • 8.

    Ciancio, V. On the general Debye equation for media with dielectric relaxation phenomena described by vectorial internal variables. J. Non-Equilib. Thermodyn. 1989, 14, 239–250.

  • 9.

    Ciancio, V.; Kluitenberg, G.A. On electromagnetic waves in isotropic media with dielectric relaxation. Acta Phys. Hung. 1989, 66, 251–276.

  • 10.

    Ciancio, V.; Ciancio, A.; Farsaci, F. On general properties of phenomenological and state coefficients for isotropic viscoanelastic media. Phys. B Condens. Matter 2008, 403, 3221–3227.

  • 11.

    Ciancio, V.; Palumbo, A. A thermodynamical theory with internal variables describing thermal effects in viscous fluids. J. Non-Equilib. Thermodyn. 2018, 43, 171–184.

  • 12.

    Ciancio, V. Derivations of the stress-strain relations for viscoanelastic media and the heat equation in irreversibile thermodynamic with internal variables. Int. J. Math. Comput. Eng. 2024, 2, 141–154.

  • 13.

    Ciancio, A.; Flora, B.F.F. Application of a generalized heat equation to ultra-fast processes in viscoanelastic isotropic medium. Int. J. Math. Comput. Eng. 2025, 3, 389–404.

  • 14.

    Ciancio, A.; Flora, B.F.F.; Ciancio, V. Derivations of the stress-strain relations for anisotropic viscoanelastic media in irreversible thermodynamics with internal variables. Atti Accad. Pelorit. Pericolanti Cl. Sci. Fis. Mat. Nat. 2025, 103, A1-1.

  • 15.

    Maxwell, J.C. On the dynamical theory of gases. Philos. Trans. R. Soc. Lond. 1867, 157, 49–88.

  • 16.

    Berezovski, A.; V´an, P. Microinertia and internal variables. Contin. Mech. Thermodyn. 2015, 28, 1027–1037.

  • 17.

    Wang, Y.C.; Ko, C.C.; Chang, K.W. Anomalous effective viscoelastic, thermoelastic, dielectric, and piezoelectric properties of negative-stiffness composites and their stability. Phys. Status Solidi B 2015, 252, 1640–1655.

  • 18.

    Bulıcek, M.; M´alek, J.; Prusa, V.; et al. On incompressible heat-conducting viscoelastic rate-type fluids with stress-diffusion and purely spherical elastic response. SIAM J. Math. Anal. 2021, 53, 3985–4030.

  • 19.

    Safa, B.N.; Santare, M.H.; Elliott, D.M. A Reactive Inelasticity Theoretical Framework for Modeling Viscoelasticity, Plastic Deformation, and Damage in Fibrous Soft Tissue. J. Biomech Eng. 2019, 141, 021005.

  • 20.

    Song, R.; Muliana, A.; Rajagopal, K. A thermodynamically consistent model for viscoelastic polymers undergoing microstructural changes. Int. J. Eng. Sci. 2019, 142, 106–124.

  • 21.

    Berjamin, H.; Destrade, M.; Parnell, W.J. On the thermodynamic consistency of Quasi-linear viscoelastic models for soft solids. Mech. Res. Commun. 2021, 111, 103648.

  • 22.

    Atanackovic, T.M.; Dolicanin, C.; Kacapor, E. Internal Variable Theory in Viscoelasticity: Fractional Generalizations and Thermodynamical Restrictions. Mathematics 2022, 10, 1708.

  • 23.

    Ciancio, A.; Ciancio, V.; Flora, B.F.F. A Fractional Rheological Model of Viscoanelastic Media. Axioms 2023, 12, 243.

  • 24.

    Kluitenberg, G.A. On heat dissipation due to irreversible mechanical phenomena in continuous media. Physica 1967, 35, 177–192.

  • 25.

    Cattaneo, C. A form of heat conduction equation which eliminates the paradox of instantaneous propagation. C. R. Acad. Sci. 1958, 247, 431–433.

  • 26.

    Vernotte, P. Les paradoxes de la theorie continue de l’equation de la chaleur. C. R. Acad. Sci. 1958, 246, 3154–3155.

  • 27.

    Joseph, D.D.; Preziosi, L. Heat waves. Rev. Mod. Phys. 1989, 61, 41–73.

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Ciancio, A.; Flora, B. F. F.; Ciancio, V. On the Evolution of Internal Variables for Anisotropic Viscoelastic Media. Nonlinear Analysis and Computer Simulations 2026, 1 (3), 12. https://doi.org/10.53941/nacs.2026.100012.
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