Static fatigue

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Static fatigue, sometimes referred to as delayed fracture, describes the progressive cracking and eventual failure of materials under a constant, sustained stress. [1] (It is different from fatigue, which refers to the deformation and eventual failure of materials subjected to cyclical stresses.) With static fatigue materials experience damage or failure under stress levels that are lower than their normal ultimate tensile strengths. [2] The exact details vary with the material type and environmental factors, such as moisture presence [3] and temperature. [4] [5] This phenomenon is closely related to stress corrosion cracking. [1]

Contents

Typical occurrence

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). Crack growth progression in glass rod.jpg
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

Stress corrosion cracking (SCC) happens when a stressed material is in a corrosive (chemically destructive) environment. [6] One example of SSC embrittlement is when moisture increases static fatigue degradation of glass. [7] SCC is also seen in hydrogen embrittlement [8] [9] and embrittlement of some polymers. [10]

Plastic Deformation (Plastic Flow)

Plastic deformation happens when stresses flatten, bend, or twist a material until it cannot return to its original shape. [11] This can create cracks in the material and decrease its lifetime. [12]

Testing

Static fatigue tests can be used to determine the lifespan of a material with different loads and environmental conditions. [13] [14] However, accurately assessing a material's true static fatigue life presents challenges, as these tests often require an extended duration and there is significant variability in the results. [13]

Examples of Static Fatigue and Stresses on Materials

Plastic pipes under water or other fluids experience hydrodynamic forces that can result in fatigue. [15] The pipes reach failure sooner as temperatures and exposure to aggressive substances increase. [15]

References

  1. 1 2 Suresh, S. (1998). Fatigue of materials (2nd ed.). Cambridge; New York: Cambridge University Press. ISBN   978-0-521-57046-6.
  2. ↑ Pelleg, Josh (2021). Cyclic Deformation in Oxides, Carbides, and Nitrides. Vol. 22. Springer. pp. 495–511. doi:10.1007/978-3-030-86118-6_15. ISBN   978-3-030-86118-6. S2CID   244421914.
  3. ↑ Laughton, M.J.; Warne, D.J.; Tricker, R. (2003). Optical Fibres in Power Systems (16 ed.). Newnes. pp. 37–1, 37-3 –37-17. doi:10.1016/B978-075064637-6/50037-X. ISBN   978-0-7506-4637-6.
  4. ↑ Kingery, W.D. (1976). Introduction to ceramics . New York: Wiley. ISBN   978-0471478607.
  5. ↑ Ebel, A.; Caty, O.; Rebillat, F. (2022). "Effect of temperature on static fatigue behavior of self-healing CMC in humid air". Composites Part A: Applied Science and Manufacturing. 157: 106899. doi: 10.1016/j.compositesa.2022.106899 . S2CID   247148726.
  6. ↑ Raja, V.S.; Tetsuo, Shoji (2011). Stress Corrosion Cracking. Woodhead Publishing. pp. 245–272. doi:10.1533/9780857093769.3.245. ISBN   978-1-84569-673-3.
  7. ↑ Wiederhorn, S. M.; Bolz, L. H. (1970-10-01). "Stress Corrosion and Static Fatigue of Glass". Journal of the American Ceramic Society. 53 (10): 543–548. doi:10.1111/j.1151-2916.1970.tb15962.x. ISSN   1551-2916.
  8. ↑ Lou than, M.R. "Hydrogen Embrittlement - Office of Scientific and Technical Information" (PDF).
  9. ↑ Murakami, Y.; Kanezaki, T.; Matsuoka, S. (2008). "Hydrogen Embrittlement Mechanism in Fatigue of Austenitic Stainless Steels". Metallurgical and Materials Transactions A. 39 (6): 1327–1339. Bibcode:2008MMTA...39.1327M. doi: 10.1007/s11661-008-9506-5 . S2CID   137234625.
  10. ↑ Brown, Norman; Parrish, Mark F. (1974). Bishay, Adli (ed.). Recent Advances in Science and Technology of Materials. Springer US. pp. 1–13. doi:10.1007/978-1-4613-4538-1_1. ISBN   9781461345404.
  11. ↑ Pfeifer, Michael (2009). "Chapter 6 - Degradation and Reliability of Materials". Materials Enabled Designs. Butterworth Heinemann. pp. 161–187. doi:10.1016/B978-0-7506-8287-9.00006-9. ISBN   978-0-7506-8287-9 – via Science Direct.
  12. ↑ Wang, G.S.; Blom, A.F. "Effect of Large Local Plastic Flow on the Fatigue Life of Metallic Materials". Aeronautics Division– via The Swedish Defence Research Agency.
  13. 1 2 Wilkins, B.J.; Dutton, R. (March 1976). "Static Fatigue Limit with Particular Reference to Glass". Journal of the American Ceramic Society. 59 (3–4): 108–112. doi:10.1111/j.1151-2916.1976.tb09442.x.
  14. ↑ Kelly, A.; Zweben, C.; Sims, G.D.; Broughton, W.R. (2000). Comprehensive Composite Materials (2.05 - Glass Fiber Reinforced Plastics—Properties). Vol. 2. Pergamon. pp. 151–197. doi:10.1016/B0-08-042993-9/00181-9. ISBN   978-0-08-042993-9.
  15. 1 2 Farshad, Mehdi (2006-01-01), Farshad, Mehdi (ed.), "7 - Fatigue, corrosion, and wear", Plastic Pipe Systems, Oxford: Elsevier Science, pp. 153–165, ISBN   978-1-85617-496-1 , retrieved 2023-04-15
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