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The repairing process of structures using bonding of composite materials is an efficient and economic way of increasing service life of damaged structures. The finite element method is developed and applied to assist in the design, assessment and optimization of the proposed plans before they are implemented, therefore reducing cost and time. In this study, the finite element method is used to analyze the behavior of a repaired crack using single and double circular composite patches by determining the stress intensity factor reduction. The effects of geometrical and mechanical properties of the patch on the fracture parameters are highlighted. The results show that the thickness gain and the reduction of the asymptotic value of the SIF in the case of the double patch is 7% when compared to the single one. Thus, the gain in the thickness decreases when the thickness of the bonded patch increases up to a value eP = 0.8 mm and beyond this value, it starts increasing. However, an inverse behavior occurs for the mixed mode. In addition, whatever is the size of the strengthened crack, the gain in thickness exceeds 16% in mode I and 20% in mixed mode. [ABSTRACT FROM PUBLISHER]

The effectiveness of FRP rehabilitation of deteriorating and under-strength reinforced concrete beams depends not only on the properties of the FRP material, but also on the characteristics of other materials in the system, characteristics of the bond, and the relative nature of properties of materials at the interfaces. Response is also affected by the cracked condition of the beam prior to the external bonding of the FRP. This paper reports on a fundamental investigation into the effect of various design parameters using a finite element analysis approach, which not only provides characteristics of response but also enables identification of damage mechanisms and their progression to failure. It is shown that the highest level of strengthening is not always due to use of maxima of the parameters, but rather on the interaction between them. Interface bond strength and fracture energy are shown to have a significant effect on load capacity, ductility and transition of failure modes from debonding within concrete, to FRP rupture, and to debonding within the adhesive itself. [ABSTRACT FROM AUTHOR]

This article presents the results of numerical analyses of concrete cylinders (i.e., columns) confined in composites jackets. The specimens were subjected to uniaxial compression and the analysis was carried out using a non-linear finite element method. Various parameters such as wrap thickness, fiber orientation, concrete strength, and interfacial bonding were considered. Three different wrap thicknesses (0.9, 1.8, and 2.7 ram), fiber orientation of 0°, ±15°, ±30°, and ±45° with respect to the hoop direction, and concrete strength values ranging from 20 MPa to 40 MPa were investigated. The finite element analysis results were in good agreement with experimental data presented by other researchers. The numerical analysis results demonstrated significant enhancement in the compressive strength, stiffness, and ductility of the CFRP-wrapped concrete cylinders compared to unconfined concrete cylinders. The stress-strain response of cylinders was greatly affected by analysis parameters. [ABSTRACT FROM AUTHOR]