NACE - International Corrosion Conference Series | Year: 2014
Fiber Reinforced Polymer (FRP) repair systems on pipe substrates have been used successfully for leak sealing and for reinforcement. Due to corrosion, mechanical damage, or both, some small defects such as pinholes, cracked welds and small punctures can be repaired by such composite repair systems. The repair method consists of the design of a circumferential composite wrap which is laid-up and bonded to the pipe substrate, in the field, where a defect exists or is expected to exist. The effectiveness of the composite repair system is highly dependent on the adhesive fracture toughness between the two substrates, pipe and composite. The interfacial fracture toughness through the use of small circular defects, known as "blisters", has been characterized through the use of the "blister test". In some cases a repair may not have proper surface preparation in the immediate defect area due to severe corrosion. However, proper surface preparation is available in areas slightly removed from the defect. The repair for this type of defect will create a large encapsulated blister. Although large, the general shape of the blister and its front can be easily controlled. This study analyzes one textile glass fiber/epoxy composite repair system. This paper presents the results of an investigation including theoretical analysis, full-scale experimentation, and analysis of results to better understand and design reliable methods to design effective repairs. © 2014 by NACE International.
Champagne T.M.,Michigan Technological University |
Barkdoll B.D.,Michigan Technological University |
Gonzalez-Castro J.A.,South Florida Water Management District |
Journal of Hydraulic Engineering | Year: 2016
Experiments in a stilling basin model with air injected at its downstream end exhibited plunging flow resulting in a downward roller, return flow along the bottom, and a downstream near-bed flow after the plunging flow impingement point. Turbulence measurements showed that air injection reduces turbulence both at the exit of the stilling basin and near the downstream bed. Thus the effect of air injection as a modifier of the turbulence structure of the flow downstream of the stilling basin is postulated as a plausible explanation for the observed scour reduction. © American Society of Civil Engineers.
NACE - International Corrosion Conference Series | Year: 2015
Composite repair systems for pipe have been used successfully for leak sealing and reinforcement of pipework in the process industries. Their use has also expanded into pipeline integrity to address corrosion and mechanical damage, much like welded steel sleeves. Composite repairs are designed to reduce the strain in damaged areas of pipe to an allowable stress. Most composite repair systems have a modulus in the range of 2-12 Msi(14-83 GPa) which is about 15-2.5 times less than that of steel. The amount of reinforcement required to reduce the stresses in the steel substrate is a function of the wall loss of steel and the modulus of the composite repair system. A repair system should be a minimum of 2.5-15 times thicker than the amount of steel lost due to substrate damage. By utilizing a composite repair system whose modulus is higher than steel it is possible to design a repair thickness less than that of what was originally lost. In addition higher levels of strain reduction are possible with thinner repairs. In this paper FEA analysis, mechanical characterization and full scale testing on dents is conducted to characterize the performance of an Ultra High Modulus moisture cured composite repair system. © 2015 by Nace International.
Ramakrishna T.V.,Koneru Lakshmaiah College of Engineering |
Madhav B.T.P.,Koneru Lakshmaiah College of Engineering |
Bhagyalakshmi N.,NRI |
Venkateswarulu K.,Eswar Engineering College
ARPN Journal of Engineering and Applied Sciences | Year: 2015
A compact CPW fed antenna is designed for the dual band operation. Here electromagnetic band gap structures of rectangle-shaped lattices are placed for the harmonic suppression. We observed that EBG structures are not only exhibiting the band stop characteristics, but also help to magnify the proposed antenna bandwidth. The rectangular lattice like EBG's have a frequency band gap and high surface impedance characteristics, which generally represent as in-phase reflection band. We succeeded in integrating the rectangular lattice EBG's in compact slot antenna with a CPW feeding line, to decrease the surface wave losses and bandwidth enhancement. The complete antenna analysis with radiation characteristics are presented in the current study. © 2006-2015 Asian Research Publishing Network (ARPN).
Materials Performance | Year: 2013
Fiber-reinforced polymers (FRPs) are being used to repair damaged pipes in a wide variety of applications. FRPs have been successfully used in many industries ranging from aircraft manufacturing to electronic circuit boards. Tey are useful for repairing steel pipes because a pipe section can be reinforced without shutting down operations. FRPs can be used in a range of chemical and thermal environments, and can also be used in undersea repairs.