scholarly journals Iterative tomography of pipes during operation

Author(s):  
S. A. Zolotarev ◽  
V. L. Vengrinovich ◽  
S. I. Smagin

The pipe wall thickness was estimated based on three-dimensional images of the pipe recovered from several X-ray projections, which were made in a limited angle of view. Since the effects of scattered radiation and beam hardening are up to 50 % of the main radiation, ignoring them leads to blur of the image and inaccuracy in determining dimensions. To restore pipe images from projections, a volume and/or shell representation of the pipe is used, as well as iterative Bayesian methods. Using these methods, the error in estimating the pipe wall thickness from the projection data can be equal to or less than 300 μm. It has been shown that standard X-ray projections on the film or imaging plates used to obtain data can be used to restore pipe wall thickness profiles in factory conditions.

Author(s):  
S. A. Zolotarev ◽  
P. S. Savenia ◽  
K. A. Zhukov ◽  
M. A. Sednina

The possibility of an accurate estimation of the pipe wall thickness measured directly from the reconstructed image of the pipe, reconstructed from only a few X-ray projections made in a limited viewing angle, is discussed. Since the effects of radiation scattering and X-ray beam hardening distort up to 50 % of the primary radiation, ignoring these effects leads to blurred images, strong artifacts, and inaccurate sizing. A computerized technique has been developed that takes into account the contribution of scattered radiation and the hardening of the X-ray beam. Iterative Bayesian reconstruction techniques are then used to reconstruct the pipe image using the volumetric and surface-oriented representation of the pipe. Using these methods, the error in estimating the pipe wall thickness can be increased to 300 microns.


2020 ◽  
pp. 49-52
Author(s):  
R.A. Okulov ◽  
N.V. Semenova

The change in the intensity of the deformation of the pipe wall during profiling by drawing was studied. The dependence of the strain intensity on the wall thickness of the workpiece is obtained to predict the processing results in the production of shaped pipes with desired properties. Keywords drawing, profile pipe, wall thickness, strain rate. [email protected]


2021 ◽  
pp. 143-147
Author(s):  
Charles Becht

While the exercise of pressurizing a piping system and checking for leaks is sometimes called pressure testing, the Code refers to it as leak testing. The main purpose of the test is to demonstrate that the piping can confine fluid without leaking. When the piping is leak tested at pressures above the design pressure, the test also demonstrates that the piping is strong enough to withstand the pressure. For large bore piping where the pipe wall thickness is close to the minimum required by the Code, being strong enough to withstand the pressure is an important test. For small bore piping that typically has a significant amount of extra pipe wall thickness, being strong enough is not in question. Making sure that the piping is leak free is important for all piping systems.


1998 ◽  
Vol 5 (3) ◽  
pp. 1088-1089 ◽  
Author(s):  
Norio Watanabe ◽  
Sadao Aoki

The depth resolution of a soft X-ray hologram is much worse than its transverse resolution because a single soft X-ray hologram has a small numerical aperture. To obtain a three-dimensional image, in-line holograms of a specimen were recorded from various directions and reconstructed to obtain two-dimensional projection data. Then, a three-dimensional reconstruction was performed by back-projection of these reconstructed holograms. Three-dimensional images of a tungsten wire of diameter 10 µm and a fossil of a diatom were obtained.


Author(s):  
Philippe Gilles ◽  
Alexandre Brosse ◽  
Moi¨se Pignol

This paper presents ductile initiation calculations and growth simulations of a surface crack up to pipe wall breakthrough. For validation purpose, one of the two BIMET configurations is selected. The EC program BIMET has been carried out to analyze the ductile tearing behavior of DMWs through experiments and computational analyses. In the mock-up, the initial defect is an external circumferential defect located close to the weld-ferritic interface, with a depth of one third of the wall thickness. During the test, the crack extended up to two third of the pipe wall thickness. The aim of the study is to simulate the crack initiation and growth, to compare the results with the experimental records and to continue the ductile crack growth up to pipe wall break-through.


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