Analysis of welding
Transforming Stress Limited staff have used computer modelling methods to make predictions of welding heat flow, welding stresses, residual stresses and distortion since the late 1980s. Our staff have experience of using Finite Element Analysis to model arc, power beam and friction welding processes. Our staff have also collaborated with graduate student research on the thermally-related irreversible material behaviour of aluminium alloys and ferritic steels.
Flaw assessments of welded fabrications are known as Fitness for Purpose (FFP), Fitness for Service (FFS) or Engineering Critical Assessments (ECA). Such assessments use the principles of fracture mechanics to demonstrate that safe structures are defect tolerant.
Fracture mechanics combines the fundamental analytical concepts related to the deformations of material containing cracks with the underlying material behaviour mechanisms of microstructures that suffer extremes of loading.
Transforming Stress Limited staff have developed FEA and analytical techniques for defect assessment since the early 1980s.
The fatigue of welded joints
Welding is has widespread use in the manufacture of engineering structures and consumer products. The use of welding provides a relatively cost effective and simple method for the fabrication of relatively complex shapes and structures. It is important, however, that design engineers properly assess the strengths of welded structures, especially if their service loading is likely to include a significant cyclic component where fatigue could initiate at the weld toes or weld root.
Codes and standards have been developed for the proper design of welds that experience cyclic loads. The British standard BS 7608:2014 ('Guide to fatigue design and assessment of steel products') contains guidance on stress analysis (Annex C) that was written by Transforming Stress Limited staff (during employment before they joined Transforming Stress Limited).