PSI - Issue 19

Yoichi Yamashita et al. / Procedia Structural Integrity 19 (2019) 123–129 Yamashita et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 7 Fatigue crack growth length during fatigue test before and after constructing the arresters to the mockup of steel bridge deck.

5. Conclusions “Crack growth arrest or retardation system” has been developed against fatigue crack, by using the arrester of gourd-shaped-insert-plates to close fatigue crack and reduce crack tip opening displacement and stress concentration at the fatigue crack tip. The Arresters were applied to CT (Compact Tension) specimens and also mockup of steel bridge deck, in order to validate performance of the system. In the tests using CT specimens, fatigue crack growth rates of the specimens with arrester were 1/10 ~ 1/2 of those without arrester. And apparent threshold stress intensity factor range was increased by about 10~20 MPa√ through using only few gourd-shaped arresters. Also, the arrester was applied to the fatigue crack in the mockup of steel bridge deck. Without arrester, fatigue crack growth occurred in accordance with the increase of loading cycles, on the other hand, fatigue crack growth was arrested after application of the arrester in the mockup of steel bridge deck. And to enable quantitative fatigue life assessment in fatigue design, fracture mechanics based-crack closure model with spring elements for the arrester has been verified with good accuracy for fatigue crack growth rate in the tests using CT specimens. ASTM E647 - 15e1, 2015. Standard Test Method for Measurement of Fatigue Crack Growth Rates, ASTM International, West Conshohocken, PA, www.astm.org Ayatollahi, M.R., Razavi, S.M.J., Chamani, H.R., 2014. Fatigue life extension by crack repair using stop - hole technique under pure mode - I and pure mode II loading conditions. Procedia Engineering 74, 18–21. ITW Performance Polymers, https://itwperformancepolymers.com/products/plexus Kühn, B., 2008. Assessment of existing steel structures - recommendations for estimation of remaining fatigue life, Procedia Engineering 66, 3 11. Paris, P.C., 1957. The mechanics of fracture propagation and solutions to fracture arrester problem. Document D2 - 2195, The Boeing Company. Tada, H., Paris, P.C., Irwin, G.R., 1973. The stress analysis of cracks handbook, Del Research Corporation, Hellertown, PA. References