The Paton Welding Journal, 2013, №06



2013 №06 (01)

2013 №06 (03)

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The Paton Welding Journal, 2013, #6, 11-14 pages  

DETERMINATION OF CONTACT PRESSURE OF REINFORCING SLEEVE IN REPAIR OF PIPELINES WITH SURFACE DEFECTS

V.I. MAKHNENKO, O.I. OLEJNIK and V.M. SHEKERA

E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
An important step of maintaining the operability of main land pipelines is periodical technical diagnostics and, if required, repair operations in the sections with detected inadmissible defects. One of the promising methods to restore the load-carrying capacity of the wall with typical defects (in particular, thinning of main pipeline wall as a result of local corrosion loss of metal) is mounting reinforcing structures of the type of welded bands and leak-tight sleeves. This enables redistribution of stresses from service load between pipe walls and repair structure so that the detected defect was admissible in the working conditions. In order to do it, it is necessary to guarantee sufficient efficiency of repair, in particular, ensure the required contact pressure in the area of surface interaction of the pipe and reinforcing structures. For this purpose, a numerical-experimental procedure has been developed for assessment of the value of contact pressure at mechanical interference of the repair structure (mounting in the defective section of the main pipeline), and methods of numerical assessment of the nature of load redistribution in «pipeline-repair structure» contact pair were proposed, which allow analyzing the influence of repair parameters on the degree of restoration of load-carrying capacity of a pipeline with specific defect. In addition, a test sample of mechanical deformometer was developed, with a design adapted to measurement of circumferential displacements in the wall of reinforcing structure at its mounting on the pipeline. Preliminary laboratory investigations confirmed the effectiveness of the proposed procedure that allows recommending it for application at repair of operating main pipelines. 11 Ref., 1 Table, 5 Figures.
 
 
Keywords: pipeline, thinning defect, repair, reinforcing welded structure, contact pressure, circumferential deformations, mechanical deformometer
 
 
Received:                26.02.13
Published:               28.06.13
 
 
References
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