Issue 49

E. Abdelouahed et alii, Frattura ed Integrità Strutturale, 49 (2019) 690-697; DOI: 10.3221/IGF-ESIS.49.62 696 shown in this figure that the more the crack increases the more the repair becomes useless. This can be explained by the fact that the working area (transfer) of the adhesive is limited when the crack increases. L crack 0 2 4 6 8 10 K 1 (MPa.m 0.5) 5.6 5.8 6.0 6.2 6.4 6.6 6.8 7.0 Boron/epoxy Carbon/epoxy Glass/epoxy Pipeline Steel API 5L X70 , e pipe = 4 mm Composite Patch, e patch =2mm, L patch =c st Adhesive FM 73, e a = 0.2 mm Crack length a=Variable Figure 8 : SIF variation according to the crack length of the pipeline C ONCLUSION his study has been focused by a numerical simulation on the evaluation of the stress intensity factor under different effect of: temperature variation, pressure variation, patch variation, patch thickness variation, and crack size variation of a structure steel pipe cracked and repaired by composite patch. The following conclusions could be deduced from the obtained results: • Patches and adhesive play a crucial role on the repair. Any reduction efficiency is limited by the ability of the adhesive to resist. • The efficiency repair is directly related to the stiffness of the composite patch. If the composite is more rigid, the repair efficiency is elevated. • An increase in the thickness of the patch increases the rigidity, the consequence, the increase in the efficiency. • The reparation efficiency decreases with the increasing length and crack depth. Which subsequently undermines the work of the adhesive. • Thermal stresses weaken the capacity of the adhesive by accumulating loads, which explains the increase in the stress intensity factor. R EFERENCES [1] Manne, A., Mendelsohn, R., Richels, R. (1995). A model for evaluating regional and global effects of GHG reduction policies, Energy Policy, 23 (1), pp. 17-34. [2] Sydney, T., Richard A. D. (2003). Review of ways to transport natural gas energy from countries which do not need the gas for domestic use, Energy, (28), pp. 1461–1477. [3] Ibrahim, H., Ilinca, A., Perron, J. (2008). Energy storage systems—Characteristics and comparisons, Renewable and Sustainable Energy Reviews, (12), pp. 1221 – 1250. [4] Katnam, K.B., Da Silva, L.F.M., Young, T.M. (2013). Bonded repair of composite aircraf t structures: A review of scientific challenges and opportunities, Progress in Aerospace Sciences, (61), pp. 26–42. [5] Wu, M., Johannesson, B., Geiker, M. (2012). A review: Self-healing in cementitious materials and engineered cementitious composite as a self-healing material, Construction and Building Materials, (28), pp. 571–583. [6] Djokic, D., Rogers, A., Lee-Sullivan, P., Mrad, N. (2002). Residual stress development during the composite patch bonding process: measurement and modeling, Composites, (A33), pp. 277-288. T