1. Laser Treatment Modeling Capabilities at Rensselaer-Hartford Ernesto Gutierrez-Miravete Rensselaer at Hartford ernesto@rh.edu

2. Background Thermal modeling work starts at Rensselaer- Hartford in 1988. Initial work focused on analytical solutions (Rosenthal) and simple numerical methods. Collaborative with Dr. Tony Giamei at UTRC in the area of thermal modeling of arc welding systems starts in 1989 and continues through the late 1990’s and to date.

3. Features of Current Code: General Simulates thermal and microstructural effects of beam heating with realistic energy input distributions for 3D geometrical shapes of real materials.

4. Features of Current Code: Heat Source Heat source can be located on any surface of the 3D body. Heat source can have an arbitrary distribution of energy input which can also vary with time. Heat source can be stationary or move in a specified manner.

5. Features of Current Code: Physical Processes Heat conduction with change of phase(s) in treated material. Microstructural evolution (grain growth, DAS, precipitate size) Radiation, vaporization and fluid flow.

6. Features of Current Code: Geometry Rectangular Cartesian –thin and thick plates –solid parallelepipeds Cylindrical Polar –Solid and hollow cylinders Other –Non-orthogonal coordinates (under development)

7. Current Software Features: Algorithm Numerical solution algorithm is a special implementation of the method of Finite Differences. Nonlinear material behavior is accurately handled via the Enthalpy formulation and an explicit scheme. Extensively tested and optimized on supercomputers and workstations at UTRC.

8. Current Software Features: Computational FORTRAN implementation. Automatic meshing; several choices are available for mesh type and spacing. Adaptive meshing option also available. Runs at high speed on a workstation or a modern PC. Restart capability (good for long simulations).

9. Current Software Features: Output The following quantities are computed and saved to file: –Temperature and thermal gradient vs time. –Melting, solidification and evaporation rates. –Abladed zone (keyhole), fusion zone and mushy zone sizes and shapes. –Microstructural features such as dendrite arm, grain and precipitate size distribution.

10. Current Software Features: Postprocessing Post processing includes graphics suitable for workstation or PC and realistic color maps are available. Virtual thermocouple array can be placed anywhere inside and on the external surface of the body for closer examination of results.

11. Current Software Features: Materials A database of ten engineering materials (metals and ceramics) is available to users of the code on command. Data for additional materials can readily be added to the database.

12. Current Software Features: Environment Heat dissipation to the surrounding environment by convection and radiation mechanisms. Heat sinking clamps can be placed anywhere on the part.

13. Current Software Features: Other English or metric units. Built-in diagnostics. User-friendly setup scripts and data file formats.

14. Examples Moving Heat Source on the Surface of a Plate. Moving Heat Source Doublet on the Surface of a Plate.

15. Moving Heat Source on the Surface of a Plate

18. Moving Heat Source Doublet on the Surface of a Plate