PSI - Issue 42

Hasan Saeed et al. / Procedia Structural Integrity 42 (2022) 967–976 Hasan et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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5. Concluding remarks Finite element based calibration of a back-face strain compliance relation for an SENB specimen subjected to four point bending has been discussed. The compliance relation is based on a normalized compliance function inspired by Newman et al. (J. C. Newman et al., 2011) and has been calibrated for a wide range of normalized crack lengths, i.e., 0.05 ≤ / ≤ 0.6 . 1. The extended compliance relation has been experimentally validated by means of DCPD instrumented fatigue tests. 2. Crack length ratios obtained using back-face strain compliance agreed very well with the values obtained using the potential drop technique. 3. A slight deviation between both observed at larger values of crack length to width ratio, is attributed to non uniform crack growth. Acknowledgements The authors would like to acknowledge the financial support of the Federal Government of Belgium through the Energy Transition Fund, and the contributions of the project partners OCAS NV, Belgium Welding Institute (BIL), Otary, Parkwind and Smulders, which led to the production of test results reported in this paper. References ASTM E647-15, 2015. Standard Test Method for Measurement of Fatigue Crack Growth Rates. Bär, J., 2020. Crack Detection and Crack Length Measurement with the DC Potential Drop Method – Possibilities, Challenges and New Developments. Applied Sciences 2020, Vol. 10, Page 8559 10, 8559. https://doi.org/10.3390/APP10238559 BS 7910-2019, 2019. BSI Standards Publication Guide to methods for assessing the acceptability of flaws in metallic structures. BSI Standards Publication 490. Chaudhuri, S., 2019. The development of high-resolution crack monitoring methods to investigate the effect of the local weld toe geometry on fatigue crack initiation life. University of Southampton. https://doi.org/10.5258/SOTON/T0052 Chaudhuri, S., Crump, J., Reed, P.A.S., Mellor, B.G., 2019. High-resolution 3D weld toe stress analysis and ACPD method for weld toe fatigue crack initiation. Welding in the World 63, 1787 – 1800. De Waele, W., Trogh, S., de Tender, S., Micone, N., Hectors, K., 2020. Evaluation of fatigue crack propagation in steel ESET specimens subjected to variable load spectra. Procedia Structural Integrity 28, 253 – 265. https://doi.org/10.1016/J.PROSTR.2020.10.031 Deans, W.F., Richards, C.E., 1979. A simple and sensitive method of monitoring crack and load in compact fracture mechanics specimens using strain gages. Journal of Testing and Evaluation 7, 147 – 154. Garcia, R., Beserra, A., Pereira-Dias, D., De Assis, K.S., Mattos, O.R., 2015. Back-face strain compliance relation for SEN (B) specimens for wide range in crack lengths. NACE - International Corrosion Conference Series 2015-Janua. Gibson, G.P., 1987. The use of alternating current potential drop for determining J-crack resistance curves. Engineering Fracture Mechanics 26, 213 – 222. https://doi.org/10.1016/0013-7944(87)90198-6 Hobbacher, A., 2016. Recommendations for fatigue design of welded joints and components. Springer. Huh, Y.H., Song, J.H., 2000. Back-face strain compliance calibration for the four-point bend specimen. KSME International Journal 14, 314 – 319. https://doi.org/10.1007/BF03186424 ISO 12108, 2018. Metallic Materials: Fatigue Testing: Fatigue Crack Growth Method. Johnson, H.H., 1965. Calibrating the electric potential method for studying slow crack growth. Materials Research and Standards 5, 442 – 445. Maxwell, D.C., 1987. Strain Based Compliance Method for Determining Crack Length for a C (T) Compact (Type) Specimen. Mehmanparast, A., Brennan, F., Tavares, I., 2017. Fatigue crack growth rates for offshore wind monopile weldments in air and seawater: SLIC inter-laboratory test results. Materials & Design 114, 494 – 504. https://doi.org/https://doi.org/10.1016/j.matdes.2016.10.070 Newman, J., Yamada, Y., James, M., 2011. Back-face strain compliance relation for compact specimens for wide range in crack lengths. Engineering Fracture Mechanics - ENG FRACTURE MECH 78, 2707 – 2711. https://doi.org/10.1016/j.engfracmech.2011.07.001 Newman, J.C., Yamada, Y., James, M.A., 2011. Back-face strain compliance relation for compact specimens for wide range in crack lengths. Engineering Fracture Mechanics 78, 2707 – 2711. https://doi.org/https://doi.org/10.1016/j.engfracmech.2011.07.001 Okumura, N., Venkatasubramanian, T. V, Unvala, B.A., Baker, T.J., 1981. Application of the AC potential drop technique to the determination of