Bio-thermo-viscoelastic behavior in multilayer skin tissue

A theoretical model for skin thermo-viscoelastic behavior is proposed based on the non-Fourier bioheat transfer theory in this article. Skin tissue is regarded as a multilayer structure composed of epidermis, dermis, and subcutis, the properties of each layer is assumed to be homogeneous and thermoviscoelasticity. Analytical solutions of temperature profile and stress distribution in skin tissue are obtained, and the influence of non-Fourier effect, viscoelastic properties of skin, blood perfusion, and time-dependent thermal boundary conditions at skin surface is considered. Numerical results show that the peak stress occurred at skin surface induced by thermal injury is much larger than mechanical threshold of pain perception. The temperature profile in skin tissue may be overestimated for the long-time hyperthermia treatment when the heat convection of blood perfusion in dermis and subcutis is neglected. The thermal stress calculated based on thermoviscoelastic model is significantly lower than that based on classical thermoelastic model due to the inherent rheological properties of skin tissue. This article may be helpful in improving the fundamental understanding of complicated thermomechanical behavior of human skin and designing of biomedical devices for hyperthermia treatment.