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Vol.20, No.3, 2020, pp. 211–218 |
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FAILURE ASSESSMENT DIAGRAM (FAD) AND PATCH REPAIRING INDEX (PRI) ON DAMAGED STRUCTURE REINFORCED BY A COMPOSITE PATCH Djamel Neggaz1,2, Abdallah El-azzizi1,2, Mohammed Hadj Meliani2, Tahar Nateche1,2 1) University of Sciences and Technology, Mohammed Boudiaf USTO, Oran, ALGERIA 2) LPTPM, Hassiba Benbouali University of Chlef, Esalem City, Chlef, ALGERIA email: hadjmeliani@univ-chlef.dz
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Abstract The objective of the presented work is to understand the physical phenomena of failures in service or accidental solicitations of materials and metal structures after reparation. The effectiveness of reinforcing structures using a composite patch is presented with the aim to reduce the stress intensity near the notch-tip. The technique used to measure the principal constraints around the notch, to evaluate the constraint parameter T-stress and to determine the Notch Stress Intensity Factor (NSIF) in mode I by application of Finite Element Method (FEM) in 2D is the Abacus/CAE™ software. The line method is proposed, inspired from the volumetric method approach suggested by Pluvinage, developed for notches. The method is based on the determination of effective constraint Teff over an effective distance Xeff near the notch-tip. The effect of defect depth, composite patch fiber orientation, thickness of the adhesive and the patch were taken into consideration. A significant relaxation of damage area is noticed for the composite patch repaired specimens. The repair of the cracked structures means to increase their service life. This increase is about 70 % for the structure reinforced by a composite patch. Keywords: fracture mechanics, API X70, global approach, gas pipeline, T-stress, notch stress intensity factor |
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full article (479 kB)
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