Investigating two-dimensional mechanical and thermal behavior of skin tissue in confronting with various laser irradiation

In this paper, the transient temperature and vibration response of skin tissue to different types of laser heating sources are studied. Two-dimensional heat conduction equation of skin tissue based on the Cattaneo-Vernotte model is extracted considering the thermoelastic effect. Two-sided coupled differential equations governing heat transfer and displacement of skin tissue have been non-dimensionalized and solved numerically. Due to the appearance of extremely complicated boundary conditions, the Galerkin-based reduced-order model has been utilized to solve the equations properly. The effect of relaxation time on the temperature and vibration response of tissue has been studied. The thermomechanical response of tissue has been investigated considering various types of laser heat sources. Results indicated that the relaxation time creates a delay in the transient dynamic response of the tissue. It was also observed that when energy is delivered to skin tissue via the repetitive laser heating pulses, the relaxation time reduces the vibration amplitude of skin tissue in the radial direction as well as depth direction. The effect of the thermoelastic coupling term on the temperature response of tissue was not considerable.