Failure Assessment Diagram

A set of large welded A533B-1 steel plates tested in four-point bending to fracture, built to answer a question engineers keep asking: where exactly does welding residual stress push the assessment point on the Failure Assessment Diagram (FAD)? We first lay out the background and the shared method, then break the four specimens (LLAW / LLHT / HLAW / HLHT) into four problems, give the FAD inputs and results for each, and compare each result with the original literature, to see what residual stress and post-weld heat treatment each contribute.

FFS in one minute: can a structure with a flaw keep running? What methods do engineers use to decide?

A guide to BS 7910:2019 Clause 7 fracture assessment: starting from the two failure modes, it uses a single Failure Assessment Diagram (FAD) to tie together the fracture-mechanics principle, the K_I / σ_ref / K_r / L_r calculation chain, and the standard assessment steps — with original diagrams and a live worked example.