Thermal forming, also known as flame bending, is a thermo-mechanical technique employed in the shipbuilding industry to shape plates into intricate forms, including profiles with double curvature. It primarily involves heating steel plates using heat sources like oxy-acetylene gas torch, laser, induction heating, etc. The driving factor behind this process is the temperature gradient that develops across the plate's thickness. Given the inherent complexities of flame bending, including material non-linearity and the spatial and time-dependent temperature distribution, we contend that numerical simulations utilizing Finite Element Analysis (FEA) are better alternatives to experiments that help to circumvent the costs and time constraints associated with experimental methods.
In the present study, our emphasis is on creating and refining an effective finite element analysis model for thermal plate forming in shipbuilding. We thoroughly examine various aspects of this model.

Numerous simulations are performed to investigate the effect of various parameters such as plate thickness, heat input, flame speed, flame radius, etc. on the temperature distribution in the plate subjected to thermal forming. The concept of critical flame velocity is introduced, defined herein as the minimum flame velocity below which the plate temperature rise above the recrystallization temperature. Investigations are performed to identify the correlation between plate thickness and critical flame velocity.
To investigate the impact of cooling rate on the inherent deformations in thermally formed plates, a comparative analysis is conducted between plates cooled in air and those subjected to water jet cooling. In this study, a finite element model is developed to numerically analyze the effects of water jet cooling.
During the structural analysis of flame bending of plates, structural boundary conditions need to be applied to avoid rigid body motion and this requires fixing suitable nodes in the plate model that is discretized. It is observed that the nodes need to be selected cautiously depending on the heating pattern to get meaningful solutions. Herein, we present a spring connected plate model to address this problem. Resultant shapes of the plates subjected to various heating patterns are obtained using the spring connected model through FEA.
In the present study, numerical technique based on finite element method is used to identify effect of strain hardening in plates subjected to multiple flame passes. Moreover, the impact of cooling time in the residual deformation is also investigated.
Finally, a new heating technique, termed here as pulse heating strategy that is considered to fasten the process in thick plates is introduced and investigated through numerical techniques.