Investigation of composite coating effectiveness on stress intensity factors of cracked composite pressure vessels

The use of composite coating is among favorite reinforcement methods for repairing cracked pressure vessels. In the present study, the effects of mechanical properties and geometry of composite coatings on Stress intensity factors (SIF) is investigated. In this regard, after verification of modeling and analytical procedure, some 3D longitudinal and transverse semi-elliptical cracks in inner and outer layer of pressure vessels are modeled in FEM software. In addition, mechanical properties and thickness are adjustable. Then SIFs in throughout of the pressurized crack face were computed. Results indicate that critical crack occurred whenever inner longitudinal crack present in composite pressure vessel. Also, via 2 mm thickness of graphite/epoxy and glass/epoxy composite coatings, 55 and 43 percent reduction in Stress intensity factors (SIF) was observed, respectively. It is shown that increasing the thickness of the composite layers reduces stress intensity factor and hence can be considered as a suitable solution for reinforcement of the cracked pressure vessel in practical situations.