Multi-Beam Laser Heating of Steel: Temperature and Thermal Stress Analysis

Abstract

Laser multi-beam heating of steel sheet surface is considered. The irradiated laser spots are located along an arc to increase heated surface area during laser scanning at a constant speed. Temperature and stress fields are predicted for various number of spots along the arc. It is found that temperature and stress fields in the irradiated substrate can be controlled through proper selection of the number of irradiated spots along the arc. Increasing number of irradiated spots results in development of almost uniform high temperature and high stress fields around the arc; however, local heating and discontinuous stress field giving rise to large differences in von Mises stress occurring for reduced number of spots in the arc.

Fast Analytic Simulation for Multi-Laser Heating of Sheet Metal in GPU

“…As the number of laser beams increase (and the arc length remains the same), the oscillations of the temperature are mitigated and the temperature increases. Such a result is consistent with the analysis presented in [33]. As discussed in Section 3.3, our algorithm allows for computing easily the temperature along the arc without even requiring to calculate the temperature on the rest of the sheet, which improves the computation time for this particular case.…”

“…Each laser beam follows a straight line trajectory and together they draw an arc in the heating front (Figure 7a,b). Our algorithm is able to produce similar results to [33] despite the simplification of the analytic model (Figure 7c,d).…”

“…In order to visually compare our algorithm with other simulation approaches in the literature, the study case presented in [33] is replicated in this manuscript (Figure 7). In this study case, seven simultaneous lasers are distributed uniformly on the y -axis.…”

“…In [6,32], the FDM is used to analyze the thermal and structural impact of two independent laser beams melting a sheet metal. On the other hand, in [2,33], a thermal/stress analysis of multi-beam laser heating is performed using FEM. These simulations show that multi-beam heating reduce the thermal stresses afflicted to the material.…”

Control of spatio-temporal pattern formation governed by geometrical models of interface evolution

“…The performance and effectiveness of the proposed approach is demonstrated through numerical simulations involving a generic geometrical model of interface evolution. The proposed control method could be implemented in practice using laser arrays [28], which allow controlling the temperature around the boundary of the evolving interface, or by using a boundary control approach to achieve a desired temperature distribution inside the domain. Time-lapse imaging, segmentation and tracking algorithms could be used to observe the position of the interface in real-time.…”