View source for Static fatigue

{{merge to|Fatigue (material)|date=August 2024|discuss=Talk:Static fatigue#Merger discussion}}
{{Multiple issues|{{tone|date=September 2017}}{{technical|date=May 2022}}}}

'''Static fatigue''' describes how prolonged and constant [[cyclic stress]] weakens a material until it breaks apart, which is called failure.<ref>{{Cite book |last=In Materials |first=Woodhead Publishing |url=https://www.elsevier.com/books/creep-and-fatigue-in-polymer-matrix-composites/guedes/978-1-84569-656-6 |title=Creep and Fatigue in Polymer Matrix Composites |publisher=Woodhead Publishing |year=2010 |isbn=9780081014585 |editor-last=Guedes |editor-first=Rui Miranda |edition=1st}}</ref> Static fatigue is sometimes called "delayed fracture".<ref name=":1">{{Cite book |last=Pelleg |first=Josh |url=https://link.springer.com/chapter/10.1007/978-3-030-86118-6_15 |title=Cyclic Deformation in Oxides, Carbides, and Nitrides |publisher=Springer |year=2021 |isbn=978-3-030-86118-6 |volume=22 |pages=495–511|doi=10.1007/978-3-030-86118-6_15 |s2cid=244421914 }}</ref> The damage occurs at a lower [[Stress (mechanics)|stress]] level than the stress level needed to create a normal [[Tension (physics)|tensile]] fracture.<ref name=":1" /> Static fatigue can involve [[plastic deformation]]<ref name=":2">{{Cite journal |last1=Wang |first1=G.S. |last2=Blom |first2=A.F. |title=Effect of Large Local Plastic Flow on the Fatigue Life of Metallic Materials |url=https://www.gruppofrattura.it/ocs/index.php/ICF/ICF11/paper/viewFile/9810/9226 |journal=Aeronautics Division |via=The Swedish Defence Research Agency}}</ref> or crack growth.<ref>{{Cite book |last=Courtney |first=Thomas H. |url=https://books.google.com/books?id=QcYSAAAAQBAJ&dq=mechanical+behavior+of+material+Thomas&pg=PR3 |title=Mechanical Behavior of Materials: Second Edition |date=2005-12-16 |publisher=Waveland Press |isbn=9781478608387 |language=en}}</ref><ref>{{Cite journal |last1=Furmanski |first1=J. |last2=Rimnac |first2=C.M. |date=2011 |title=Crack Propagation Resistance Is Similar Under Static and Cyclic Loading in Crosslinked UHMWPE: A Pilot Study |journal=Clinical Orthopaedics and Related Research |volume=469 |issue=8 |pages=2302–2307 |doi=10.1007/s11999-010-1712-y |pmid=21128033 |pmc=3126950 }}</ref>  For example, repeated stress can create small cracks that grow and eventually break apart plastic,<ref>{{Cite book |last=Crawford |first=Roy. J. |url=https://www.sciencedirect.com/science/article/pii/B9780750637640500030 |title=Plastics Engineering (Chapter 1 - General Properties of Plastics) |publisher=Matthew Deans |year=1998 |isbn=9780081007099 |edition=1 |pages=1–40}}</ref> glass,<ref>{{Cite journal |last1=Grutzik |first1=S.J. |last2=Strong |first2=K.T. |last3=Rimsza |first3=J.M. |date=December 2022 |title=Kinetic model for prediction of subcritical crack growth, crack tip relaxation, and static fatigue threshold in silicate glass |journal=Journal of Non-Crystalline Solids: X |volume=16 |issue=100134|page=100134 |doi=10.1016/j.nocx.2022.100134 |bibcode=2022JNCSX..1600134G |s2cid=254308009 |doi-access=free }}</ref> or [[ceramic]]<ref>{{Cite book |last=Ruys |first=Andrew |url=https://doi.org/10.1016/C2017-0-01189-8 |title=Processing, structure, and properties of alumina ceramics |publisher=Woodhead Publishing |year=2019 |isbn=978-0-08-102442-3 |pages=71–121|doi=10.1016/C2017-0-01189-8 }}</ref> materials. The material reaches failure faster by increasing [[cyclic stress]]. Static fatigue varies with material type and environmental factors, such as [[moisture]] presence<ref>{{Cite book |last1=Laughton |first1=M.J. |url=https://doi.org/10.1016/B978-075064637-6/50037-X |title=Optical Fibres in Power Systems |last2=Warne |first2=D.J. |last3=Tricker |first3=R. |publisher=Newnes |year=2003 |isbn=978-0-7506-4637-6 |edition=16 |pages=37-1, 37-3-37-17|doi=10.1016/B978-075064637-6/50037-X }}</ref> and temperature.<ref>{{Cite book |last=Kingery |first=W.D. |url=https://archive.org/details/introductiontoce0000king |title=Introduction to ceramics |publisher=Wiley |year=1976 |isbn=978-0471478607 |location=New York |pages= |url-access=registration}}</ref><ref>{{Cite journal |last1=Ebel |first1=A. |last2=Caty |first2=O. |last3=Rebillat |first3=F. |date=2022 |title=Effect of temperature on static fatigue behavior of self-healing CMC in humid air |journal=Composites Part A: Applied Science and Manufacturing |volume=157 |page=106899 |doi=10.1016/j.compositesa.2022.106899 |s2cid=247148726 |doi-access=free }}</ref>

== Applications ==
Static fatigue tests can estimate a material’s lifetime<ref name=":0">{{Cite journal |last1=Wilkins |first1=B.J. |last2=Dutton |first2=R. |date=March 1976 |title=Static Fatigue Limit with Particular Reference to Glass |url=https://doi.org/10.1111/j.1151-2916.1976.tb09442.x |journal=Journal of the American Ceramic Society |volume=59 |issue=3–4 |pages=108–112|doi=10.1111/j.1151-2916.1976.tb09442.x }}</ref> and [[hardness]] to different environments.<ref>{{Cite book |last1=Kelly |first1=A. |url=https://doi.org/10.1016/B0-08-042993-9/00181-9 |title=Comprehensive Composite Materials (2.05 - Glass Fiber Reinforced Plastics—Properties) |last2=Zweben |first2=C. |last3=Sims |first3=G.D. |last4=Broughton |first4=W.R. |publisher=Pergamon |year=2000 |isbn=978-0-08-042993-9 |volume=2 |pages=151–197|doi=10.1016/B0-08-042993-9/00181-9 }}</ref>  However, measuring a static fatigue limit can take a long time, and it is hard to measure a material’s true static fatigue limit with full certainty.<ref name=":0" />

== Typical occurrence ==
[[File:Crack_growth_progression_in_glass_rod.jpg|thumb|Crack growth progression in a glass rod under cyclic stress (denoted by arrows). (1) shows the first crack. The cracks grow in (2) & (3) until the rod breaks in (4).]]

=== Stress corrosion cracking ===
{{Main|Stress corrosion cracking}}[[Stress corrosion cracking]] (SCC) happens when a stressed material is in a [[Corrosive substance|corrosive]] (chemically destructive) environment.<ref>{{Cite book |last1=Raja |first1=V.S. |url=https://doi.org/10.1533/9780857093769.3.245 |title=Stress Corrosion Cracking |last2=Tetsuo |first2=Shoji |publisher=Woodhead Publishing |year=2011 |isbn=978-1-84569-673-3 |pages=245–272|doi=10.1533/9780857093769.3.245 }}</ref>  One example of SSC [[embrittlement]] is when [[moisture]] increases static fatigue effects in glass.<ref>{{Cite journal |last1=Wiederhorn |first1=S. M. |last2=Bolz |first2=L. H. |date=1970-10-01 |title=Stress Corrosion and Static Fatigue of Glass |journal=Journal of the American Ceramic Society |language=en |volume=53 |issue=10 |pages=543–548 |doi=10.1111/j.1151-2916.1970.tb15962.x |issn=1551-2916}}</ref> SCC is also seen in [[hydrogen embrittlement]],<ref>{{Cite web |last=Lou than |first=M.R. |title=Hydrogen Embrittlement - Office of Scientific and Technical Information |url=http://sti.srs.gov/fulltext/WSRC-STI-2008-00062.pdf}}</ref><ref>{{Cite journal |last1=Murakami |first1=Y. |last2=Kanezaki |first2=T. |last3=Matsuoka |first3=S. |date=2008 |title=Hydrogen Embrittlement Mechanism in Fatigue of Austenitic Stainless Steels |journal=Metallurgical and Materials Transactions A |volume=39 |issue=6 |pages=1327–1339 |doi=10.1007/s11661-008-9506-5 |bibcode=2008MMTA...39.1327M |s2cid=137234625 |doi-access=free }}</ref> embrittlement of some [[polymer]]s,<ref>{{Cite book |last1=Brown |first1=Norman |title=Recent Advances in Science and Technology of Materials |last2=Parrish |first2=Mark F. |date=1974 |publisher=Springer US |isbn=9781461345404 |editor-last=Bishay |editor-first=Adli |pages=1–13 |language=en |doi=10.1007/978-1-4613-4538-1_1}}</ref> and more.

=== Plastic Deformation (Plastic Flow) ===
Plastic deformation happens when stresses flatten, bend, or twist a material until it cannot return to its original shape.<ref>{{Cite book |chapter-url=https://www.sciencedirect.com/science/article/pii/B9780750682879000069 |title=Materials Enabled Designs |chapter=Chapter 6 - Degradation and Reliability of Materials |publisher=Butterworth Heinemann |year=2009 |isbn=978-0-7506-8287-9 |pages=161–187 |doi=10.1016/B978-0-7506-8287-9.00006-9 |via=Science Direct |last1=Pfeifer |first1=Michael }}</ref> This can create cracks in the material and decrease its lifetime ultimately leading to the deformation of plastic.<ref name=":2" />

== Examples of Static Fatigue and Stresses on Materials ==
Plastic pipes under water or other fluids experience [[hydrodynamic]] forces that can result in fatigue.<ref name=":3">{{Citation |last=Farshad |first=Mehdi |title=7 - Fatigue, corrosion, and wear |date=2006-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9781856174961500082 |work=Plastic Pipe Systems |pages=153–165 |editor-last=Farshad |editor-first=Mehdi |access-date=2023-04-15 |place=Oxford |publisher=Elsevier Science |language=en |isbn=978-1-85617-496-1}}</ref> The pipes reach failure sooner as temperatures and exposure to aggressive substances increase.<ref name=":3" /> For static fatigue tests, rotating machines apply weight on the material under study causing it to bend in different directions, which weakens the material overtime.<ref>{{Citation |last=Goodman |first=Soderberg |title=MET 301: Design for Cyclic Loading |url=https://web.njit.edu/~sengupta/met%20301/cyclic_loading%20indefinite.pdf |page=1 |year=2022 |contribution=Fatigue |publisher=New Jersey Institute of Technology}}</ref>

== References ==
{{Reflist}}

[[Category:Continuum mechanics]]
[[Category:Corrosion]]
[[Category:Deformation (mechanics)]]
[[Category:Fracture mechanics]]
[[Category:Materials degradation]]