Synthesis and generalisation of welding fundamentals to design new welding technologies: status, challenges and a promising approach

The present paper addresses the renewed need to focus on the physics of welding to realise the full potential of the latest welding technologies which include fibre and disc lasers, friction stir welding and inverter power supplies. The approach to understanding, synthesis and generalisation in other engineering branches is reviewed, highlighting the central role of handbook type solution in the conceptual design stage. It is shown that the multiphysics and multicoupled aspects of welding exceed the capabilities of other engineering approaches and the methodology of scaling is proposed as a promising alternative. The application of scaling to friction stir welding is shown through an example in which the maximum temperature in the metal is generalised into a power law, experimental and numerical data are synthesised into a general correction factor, and secondary effects are captured as dimensionless groups.