This landscape draws primarily on G01N3 (material testing), G06F30 (computational design and simulation) and C22F1 (metal treatment), because fatigue and fracture assessment now spans both physical test methods and computational life-prediction models. In this dataset, G06F (digital data processing) accounts for 50 of 75 records and G01N (material analysis and testing) for 35, with smaller contributions from G16C (computational chemistry), G01M (testing machinery) and G06N (AI-based computing). A freedom-to-operate search limited to G01N alone would miss most of the computational-model filings that now make up the larger share of this space.

Filing is dominated by Chinese universities and transport-engineering institutes rather than large industrial corporations, with Hitachi standing out as one of the few clear corporate names in the set. Most institutions file independently; co-assignment is uncommon, appearing in only 4 pairs across the dataset, typically linking a university to a regional highway or road-engineering operator. There is a long tail of single-filing entrants alongside the more active academic names, so concentration at the top is moderate rather than extreme.

Filings grew from 2 in 2017 to a midpoint of 8 in 2022 and peaked at 14 in 2024, but the trend since then looks flat to declining, with several previously active filers showing 0 filings and year-over-year drops of -100% in the latest tracked year. Because patent publication typically lags filing by around 18 months, some of that apparent decline is likely a reporting artefact rather than a genuine stop in R&D activity. Anyone using this data for planning should treat the most recent one to two years as provisional and expect upward revision as later filings publish.

Relative to the dense core of S-N curve and stress-intensity-factor claims, several adjacent branches show thinner filing density: multiaxial short-crack life prediction, AI-assisted notch sensitivity modelling, buried-pipeline integrity evaluation, residual-stress-aware digital twins, and image-based crack growth measurement. These areas appear in the dataset's citation and IPC mix but have not attracted the same volume of dedicated filings as the core life-prediction and testing claims. A first claim in one of these branches would need to tie a specific measurement or model technique to a named application, such as pipeline integrity or multiaxial loading, rather than restating a generic life-prediction method.

Sixty of the 75 tracked records were filed through the China receiving office, far ahead of the United States at 5 and other jurisdictions in single digits. This reflects both the concentration of academic and infrastructure-engineering research institutions filing on domestic transport and materials projects, and the fact that many of these filings appear to be first-filed domestically rather than pursued internationally via PCT, since WIPO filings account for only 2 records. Anyone assessing competitive risk or freedom-to-operate in this field needs Chinese-language prior art coverage, not just English-language patent databases.