펄스 레이저의 피부 흡수에 의해 발생하는 열 효과 및 구조 변형 해석에 관한 연구

Abstract

ABSTRACT

Study of Thermal Effects and Structural Deformation Induced by Pulsed Laser Absorption in Human Skin

By Jae-Young Kim Advisor : Prof. Jong-Rak Park, Ph.D. Department of Photonic Engineering Graduate School of Chosun University

Studies of the thermal effects and structural deformation induced by pulse laser absorption in human skin were performed. First, simulations on the absorption of a pulsed laser in human skin were executed. Optical design and analysis software, TracePro (Lambda Research Corporation, USA), was employed for the simulations. The human skin was assumed to consist of two layers: epidermis and dermis layers. The literature was referred to for the numerical values of the optical properties for each layer. Laser parameters used for the simulations were set to be the same as those from a recently published paper on the tactile sensation evoked by laser-induced thermoelastic effects. From the Monte Carlo simulation performed with TracePro, the volumetric heat generation rate of the heat source caused by the pulsed laser absorption in the skin was obtained. Next, simulations on the thermal effects of the absorption of a pulsed laser in human skin were executed. Thermal analysis software, ANSYS Fluent (ANSYS Incorporated, USA), was employed for the simulations. Again, the numerical values for the thermal and physical properties of each layer were chosen from the literature. By using the volumetric heat generation rate obtained from the Monte Carlo simulation as the input for the thermal analysis simulation, we obtained temperature distributions on the skin surface and in the skin as a function of time. The simulation results were found to be in agreement with the experimental results. Lastly, simulations on the deformation of the skin caused by laser-induced thermoelastic effects were executed. Structural analysis software, ANSYS Mechanical (ANSYS Incorporated), was employed for the simulations. Again, the thermal and physical properties of the skin used for the simulations were selected from the literature. The spatiotemporal distribution of deformations and stresses were simulated using the temperature distributions obtained from the thermal simulations. We estimated the order of magnitudes of the deformations and stresses of the human skin achievable with the experimental conditions of the recent report on the tactile sensation evoked by laser-induced thermoelastic effects. We hope to verify the simulation results through experiments in the near future. The simulation methodology developed and presented in this paper is expected to be of great use for further studies on the development of laser technology for tactile sensations.