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Creep Literature Knowledge Graph (CreepLitKG)

CreepLitKG is an LLM + ontology-driven pipeline and knowledge graph that converts creep test metadata extracted from scientific literature into ontology-grounded RDF. It makes experimental creep data reported in publications — material identity, chemical composition, heat treatment history, microstructural features, test conditions and creep results — findable, machine-readable and queryable through a public SPARQL endpoint, and federates it into MSE-KG.

Every entity is typed with classes from the Creep Testing Ontology (CTO), derived from ISO 204:2018 — Metallic materials — Uniaxial creep testing in tension, together with the ontologies CTO reuses (BFO, RO, IAO, OBI, PMDco, NFDIcore, MWO) and measurement units from QUDT.

At a glance
IRI in MSE-KG msekg:17858428366781
rdfs:label Creep Literature Knowledge Graph (CreepLitKG)
Type nfdi:NFDI_0000009 — dataset
SPARQL endpoint https://dataportal.material-digital.de/dataset/a5b4edc4-43ef-44ff-a386-5d1f6fbbc439/fuseki/$/sparql
Endpoint node msekg:17858430496111 (nfdi:NFDI_0001095)
Licence CC0 1.0
Creator Dr. Hossein Beygi Nasrabadi
Affiliation FIZ Karlsruhe – Leibniz Institute for Information Infrastructure
Version 1.0.0 (released 2026-07-20)
Documentation https://hosseinbeyginasrabadi.github.io/Creep_Literature_Knowledge_Graph/
Repository HosseinBeygiNasrabadi/Creep_Literature_Knowledge_Graph
RDF dataset MaterialDigital Dataportal

Two URLs, two purposes

The endpoint node registered in MSE-KG points at the documentation site (https://hosseinbeyginasrabadi.github.io/Creep_Literature_Knowledge_Graph/). The queryable SPARQL endpoint is the Fuseki URL in the table above, as published in the project's own SPARQL access page. Use the Fuseki URL in a SERVICE clause.

How the graph is built

new creep paper
   → LLM4CreepLitKG              (LLM-assisted metadata extraction)
   → human check, into creep_literature_spreadsheet.xlsm
   → ./map.sh                    (xlsm → JSON → YARRRML/RML → RDF → pySHACL)
   → creep_literature_rdf.ttl
   → MaterialDigital Dataportal → public SPARQL endpoint
   → harvested into MSE-KG

The mapping lives entirely in the YARRRML file, IRIs are derived deterministically from record IDs (so re-runs are idempotent), and the pipeline exits non-zero on any SHACL violation.

Query interfaces

Interface Notes
Sparklis (guided query builder) Build queries in natural language, pre-configured with rdfs:label lexicons
PMD Dataportal Query UI Built-in editor on the dataset page
Programmatic HTTP POST, form-urlencoded, query= key — curl, Python SPARQLWrapper, … 
curl -X POST \
  -H "Content-Type: application/x-www-form-urlencoded" \
  --data-urlencode 'query=SELECT * WHERE { ?s ?p ?o } LIMIT 10' \
  'https://dataportal.material-digital.de/dataset/a5b4edc4-43ef-44ff-a386-5d1f6fbbc439/fuseki/$/sparql'

CORS

Browser-based editors hosted elsewhere (e.g. a self-hosted YASGUI) may fail against the endpoint because of CORS. The portal's own Query UI, Sparklis, and any server-side POST all work.

Locate it in the MatWerk KG

PREFIX nfdicore_dataset:         <https://nfdi.fiz-karlsruhe.de/ontology/NFDI_0000009>
PREFIX nfdicore_sparql_endpoint: <https://nfdi.fiz-karlsruhe.de/ontology/NFDI_0001095>
PREFIX textual_entity:           <http://purl.obolibrary.org/obo/IAO_0000300>
PREFIX denoted_by:               <http://purl.obolibrary.org/obo/IAO_0000235>
PREFIX has_url:                  <https://nfdi.fiz-karlsruhe.de/ontology/NFDI_0001008>
PREFIX has_license:              <https://nfdi.fiz-karlsruhe.de/ontology/NFDI_0000142>
PREFIX has_part:                 <http://purl.obolibrary.org/obo/BFO_0000051>
PREFIX rdfs:                     <http://www.w3.org/2000/01/rdf-schema#>

SELECT
  (SAMPLE(?label) AS ?kgLabel)
  (SAMPLE(?url)   AS ?sparqlEndpoint)
  (SAMPLE(?lic)   AS ?licence)
  (GROUP_CONCAT(DISTINCT ?part; SEPARATOR=" · ") AS ?creditedParts)
  (SAMPLE(?desc)  AS ?shortDescription)
WHERE {
  BIND(<https://nfdi.fiz-karlsruhe.de/matwerk/msekg/17858428366781> AS ?kg)

  ?kg a nfdicore_dataset: ;
      rdfs:label ?label .

  OPTIONAL { ?kg denoted_by:  ?e . ?e a nfdicore_sparql_endpoint: ; has_url: ?url }
  OPTIONAL { ?kg denoted_by:  ?d . ?d a textual_entity: ; rdfs:label ?desc }
  OPTIONAL { ?kg has_license: ?l . ?l rdfs:label ?lic }
  OPTIONAL { ?kg has_part:    ?p . ?p rdfs:label ?part }
}

Competency questions

The eight competency questions below are taken verbatim from the project's own docs/sparql.md. Run them against the Fuseki endpoint, or wrap them in a SERVICE clause to combine them with MSE-KG.

Prefixes used throughout:

PREFIX co:   <https://w3id.org/pmd/co/>
PREFIX cto:  <https://w3id.org/pmd/cto/>
PREFIX mwo:  <http://purls.helmholtz-metadaten.de/mwo/>
PREFIX nfdi: <https://nfdi.fiz-karlsruhe.de/ontology/>
PREFIX obo:  <http://purl.obolibrary.org/obo/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

CQ1 — From which literature sources (publications) does the creep data originate?

SELECT DISTINCT ?doi WHERE {
  ?d a nfdi:NFDI_0001037 ;   # digital object identifier
     co:PMD_0000006 ?doi .   # has value
}

CQ2 — Which materials have been creep tested?

SELECT DISTINCT ?material WHERE {
  ?id a mwo:MWO_0001099 ;        # material identifier
      co:PMD_0000006 ?material .
}

CQ3 — Which testing standards have been used for creep testing Inconel materials?

SELECT DISTINCT ?material ?standard WHERE {
  ?mid a mwo:MWO_0001099 ;
       obo:IAO_0000219 ?piece ;        # denotes creep test piece
       co:PMD_0000006 ?material .
  ?piece obo:RO_0000056 ?process .     # participates in
  ?process obo:COB_0000081 ?plan .     # intended to realize
  ?std a nfdi:NFDI_0000206 ;           # standard
       obo:RO_0000058 ?plan ;          # is concretized as
       co:PMD_0000006 ?standard .
  FILTER(CONTAINS(?material, "Inconel"))
}

CQ4 — At what temperature and applied stress was each creep test performed?

SELECT ?process ?temperature ?tempUnit ?stress ?stressUnit WHERE {
  ?process a co:PMD_0000589 ;          # creep testing process
           co:PMD_0025013 ?tq .        # changes quality (temperature)
  ?tSpec obo:RO_0000058 ?tq ;
         obo:OBI_0001937 ?temperature ;
         obo:IAO_0000039 ?tempUnit .
  ?sq a cto:CTO_1000304 ;              # mechanical stress
      obo:BFO_0000054 ?process .       # realized in
  ?sSpec obo:RO_0000058 ?sq ;
         obo:OBI_0001937 ?stress ;
         obo:IAO_0000039 ?stressUnit .
}

CQ5 — What heat treatment steps (solutionizing, aging) were applied to a test piece before creep testing?

SELECT ?process ?step ?condition WHERE {
  ?ht obo:BFO_0000062 ?process .       # heat treatment preceded by creep test
  ?desc obo:IAO_0000219 ?ht ;          # description denotes the treatment
        co:PMD_0000006 ?condition .
  OPTIONAL { ?desc rdfs:label ?step }  # "Solutionizing" / "Aging"
}
ORDER BY ?process ?step

CQ6 — What is the grain size of the material for each heat treatment condition?

SELECT ?piece ?grainSize ?unit ?agingCondition WHERE {
  ?gs a co:PMD_0020243 ;               # grain size
      obo:RO_0000080 ?cryst .          # quality of crystallite
  ?spec obo:OBI_0001927 ?gs ;
        obo:OBI_0001937 ?grainSize ;
        obo:IAO_0000039 ?unit .
  ?cryst obo:RO_0002350 ?micro .       # member of microstructure
  ?micro obo:BFO_0000050 ?piece .      # part of test piece
  ?piece obo:RO_0000056 ?process .
  ?aging obo:BFO_0000062 ?process ;
         rdfs:label "aging process" .
  ?desc obo:IAO_0000219 ?aging ;
        co:PMD_0000006 ?agingCondition .
}

CQ7 — What percentage elongation after creep fracture was observed for each test?

SELECT ?process ?elongation WHERE {
  ?q a cto:CTO_0000005 ;               # % elongation after creep fracture
     obo:BFO_0000054 ?process .
  ?spec obo:OBI_0001927 ?q ;
        obo:OBI_0002135 ?elongation .  # text value incl. uncertainty
}

CQ8 — What are the stress rupture time and steady-state creep rate measured for Inconel 718?

SELECT ?sample ?ruptureTime ?creepRate WHERE {
  ?mid a mwo:MWO_0001099 ;
       obo:IAO_0000219 ?piece ;
       co:PMD_0000006 "Inconel 718" .
  ?oid a mwo:MWO_0001015 ;             # sample identifier
       obo:IAO_0000219 ?piece ;
       co:PMD_0000006 ?sample .
  ?piece obo:RO_0000056 ?process .

  ?load a cto:CTO_0000011 ;            # loading process
        obo:BFO_0000050 ?process ;
        obo:BFO_0000199 ?rt .          # occupies temporal region
  ?rtSpec obo:OBI_0001927 ?rt ;
          obo:OBI_0002135 ?ruptureTime .

  ?cr a cto:CTO_1000035 ;              # creep rate
      co:PMD_0025006 ?process .        # process attribute of
  ?crSpec obo:OBI_0001927 ?cr ;
          obo:OBI_0002135 ?creepRate .
}

How to cite

@software{CreepLitKG,
  author  = {Beygi Nasrabadi, Hossein and Molaei, Soheil and Bayani, AmirHossein
             and Norouzi, Ebrahim and Waitelonis, J{\"o}rg and Sack, Harald},
  title   = {Creep Literature Knowledge Graph (CreepLitKG)},
  url     = {https://github.com/HosseinBeygiNasrabadi/Creep_Literature_Knowledge_Graph},
  version = {1.0.0},
  date    = {2026-07-20},
}

Sources