Engineering

Third of four problems on the welded A533B-1 plate: the HLAW specimen — as-welded, warmed to −30 ℃, with the load raised into the high load-ratio (large-plasticity) regime. We run it in mechCalc's BS 7910 Clause 7 fracture assessment calculator to see how the assessment calls plastic collapse once L_r=1.80 exceeds the cut-off value L_r,max, and why the relative weight of residual stress is diluted by plasticity at high L_r so that fracture toughness becomes the governing factor.

Second of four problems on the A533B-1 welded plate: same temperature as Problem 1 LLAW (−120 ℃), same region, same measured residual-stress profile — the only variable is that post-weld heat treatment (PWHT) was applied. Here we run LLHT in mechCalc's BS 7910 Clause 7 fracture-assessment calculator and watch a counter-intuitive result: its primary SIF is actually higher than LLAW, yet the assessment point lands lower, because the residual K_I^S drops from 46 to 5.

One of the four A533B-1 welded-plate problems: the LLAW specimen — as-welded, −120 ℃, low load ratio. It is the first of the four to fracture (1.27 MN). This post walks step by step through entering, computing, and reading the FAD in mechCalc's BS 7910 Clause 7 Fracture Assessment Calculator, to see exactly how the residual K_I^S of 46 MPa·m^0.5 pushes the deepest-point assessment point to K_r=2.59, far beyond the Failure Assessment Line.

In the fracture-mechanics and fitness-for-service (FFS) literature, FITNET is a name you cannot avoid. This article traces the origins of the FITNET EU project from public sources: how it descends from SINTAP, who led and funded it, its scale, what the four modules of the FITNET FFS Procedure each cover, and why its fracture module is highly comparable to BS 7910.

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.

A walkthrough of the two K_mat estimation routes in BS 7910:2019 Annex J — the lower-shelf equation and the Master Curve — with full derivations, the T_K confidence margin explained, and three worked verification examples.

Explains eccentric clamping and eccentric loading in VDI 2230: the two eccentricity parameters, the corrected resiliences, the load factor, the substitutional moment of inertia, and the clamp load needed to prevent opening.

A full VDI 2230 tapped thread joint (ESV/TTJ) worked example. Compared with the previous DSV example, it highlights the key ESV differences in the resilience calculation, the supplement to the clamped-part resilience in the load factor, the nut-region elastic modulus and the length of engagement check, and lists every input you need to re-run the case in the calculator.