The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	A thermoelastic model applied to stress control in laser heating of ceramics
Author:	Wagner, Jeff Alexander
View Online:	njit-etd1994-136 (xi, 63 pages ~ 1.9 MB pdf)
Department:	Department of Physics
Degree:	Master of Science
Program:	Applied Physics
Document Type:	Thesis
Advisory Committee:	Murnick, Daniel Ely (Committee chair) Goode, Philip R. (Committee member) Li, Yuan (Committee member)
Date:	1994-05
Keywords:	Thermoelasticity Thermal stresses Ceramics -- Finishing Laser beams
Availability:	Unrestricted
Abstract:	Localized laser heating is widely used in materials processing. In extending these techniques to materials with relatively low thermal conductivities and ductilities such as ceramics and glasses, existing methods must be modified to control the high thermal stresses which are associated with the localized heating of these materials. Thermal profiles must be designed to minimize damage to regions adjacent to the processed area. To achieve this with single beam sources the power and radius can be varied in time, or the beam can be moved across the surface in a programmed pattern to achieve the desired thermal profile. In this work the thermoelastic effects associated with fixed and moving beam sources are examined in light of the application described above. Finite difference models of the temperature rise and resulting stresses and strains for the surface heating of a semi-infinite half-space are presented. These simulations are then compared to experimental results obtained with a CO, laser aimed with computer controlled optics.