| Author(s) |
Noshin Tasnim Tuli, Meysam Faegh, Ehsan Setayesh, Andrew O’Connor, Louise Littles, Jeffrey W. Sowards, Azadeh Haghighi, Tarasankar DebRoy, Tuhin Mukherjee |
| Abstract Scope |
Laser welding in space presents unique challenges due to the extreme environmental conditions of low gravity, low pressure, and low temperature encountered in near-orbit, lunar, and Martian environments. This work presents a three-dimensional transient numerical model of keyhole-mode laser welding developed to predict weld behavior under such conditions for austenitic stainless steel 316. The governing equations of conservation of mass, momentum, and energy are solved simultaneously, incorporating relevant welding process parameters and thermophysical properties of SS 316 alongside the environmental conditions characteristic of space. The model predicts temperature and velocity fields, keyhole geometry, fusion zone dimensions, thermal cycles, cooling rates, and solidification parameters. Model predictions are validated against available experimental data, demonstrating strong agreement. Parametric studies are conducted to isolate and quantify the individual and combined effects of low temperature, low pressure, and low gravity on weld pool dynamics, keyhole formation, and fusion zone geometry across near-orbit, lunar, and Martian conditions. To provide deeper physical insight into the governing transport mechanisms, the results are further interpreted through key dimensionless numbers, including the Péclet, Marangoni, Fourier, Rayleigh, and Weber numbers, enabling a systematic assessment of the relative contributions of conductive and convective heat transfers and fluid flow. The findings of this work advance the fundamental understanding of laser welding behavior in space and provide a quantitative framework to support the development of in-space manufacturing and repair capabilities for future crewed and robotic space missions. |