Three-Dimensional Ultrasonic Crack Detection in Anisotropic Materials

1997 ◽  
Vol 9 (2) ◽  
pp. 59-79 ◽  
Author(s):  
J. Mattsson ◽  
A. J. Niklasson ◽  
A. Eriksson
Keyword(s):  
Crack Detection ◽  
Three Dimensional ◽  
Anisotropic Materials

Predicting the Failure Pressure of SCC Flaws in Gas Transmission Pipelines

2012 ◽  
Author(s):  
Raymond R. Fessler ◽  
David Batte ◽  
Gabriela Rosca ◽  
Greg Van Boven ◽  
Gary Vervake ◽  
...  
Keyword(s):  
Input Data ◽  
Crack Detection ◽  
Three Dimensional ◽  
Failure Pressure ◽  
Service Failures ◽  
Pipe Burst ◽  
Level Ii ◽  
Wide Range ◽  
Natural Gas Transmission ◽  
Transmission Pipelines

An important requirement for the management of stress-corrosion cracking (SCC) in natural gas transmission pipelines is the ability to predict accurately the burst failure pressure of flaws that have been discovered, particularly those found by crack detection in-line inspection (ILI). ASME B31.8S contains guidance for categorization of SCC based on predicted failure pressure for the cracks. Assessment of the segments is based on the severity category of SCC. As part of a Joint Industry Project (JIP) addressing the management of SCC in gas transmission pipelines, eight operators have assembled information relating to 85 in-service failures, hundreds of hydrostatic test failures, and dozens of pipe burst tests in which failure was due to SCC. Within the database are a wide range of pipe grades and sizes. Failures are due to both high pH and near-neutral pH SCC, and the flaws that initiated failure range from simple thumbnails to complex groups of cracks in a three-dimensional cluster. This paper presents some of the results from a comprehensive comparative study of the failure pressure predictions obtained using API 579 Level II, ln-secant, CorLAS® and PAFFC methods for around 40 of the best-characterized datasets within the above database. From the results obtained, the sensitivities of the calculations to the calculation method used and to the input data, such as flaw profile, are examined. The results provide useful guidance to all those involved in predicting failure pressures as part of their threat management activities.

scholarly journals An End-To-End Model for Pipe Crack Three-Dimensional Visualization Based on a Cascade Neural Network

2020 ◽  
Vol 10 (4) ◽  
pp. 1290
Author(s):  
Xia Fang ◽  
Yang Wang ◽  
Yong Li ◽  
Jie Wang ◽  
Libin Zhou
Keyword(s):  
Neural Network ◽  
Crack Detection ◽  
Three Dimensional ◽  
Side Wall ◽  
Long Time ◽  
End To End ◽  
Cascade Neural Network ◽  
Ambiguous Data ◽  
High Level ◽  
Navigation Equipment

With the continuous progress of machine vision technology, crack detection in pipelines has been greatly improved. For crack detection in deep holes, inner tubes, and other environments, it is not only necessary to detect the existence of cracks, but also to collect important information regarding the crack detection direction for further analysis. Because shooting with a frontal field of view causes the real side wall images to produce certain distortions, the detection and calibration of cracks requires a certain amount of professional technology and time. It usually takes a long time to collect the image to eliminate the distortion, and then to identify the crack and mark the direction according to the data line. Therefore, a simple and efficient end-to-end neural network model for crack recognition and three-dimensional visualization are proposed by using a cascade network and simple recognition technology in conjunction with inertial navigation equipment. In addition, we screen the crack data via pixel calibration and eliminate the ambiguous data to make the visualization more accurate. Experiments in pipelines and burrows show that the accuracy, performance, and efficiency of the proposed method reached a high level.

scholarly journals A nonlinear thermomechanical formulation for anisotropic volume and surface continua

2020 ◽  
Vol 25 (11) ◽  
pp. 2076-2117 ◽  
Author(s):  
Reza Ghaffari ◽  
Roger A Sauer
Keyword(s):  
Conservation Laws ◽  
Finite Temperature ◽  
Deformation Gradient ◽  
Three Dimensional ◽  
Anisotropic Materials ◽  
Shell Material ◽  
Multiplicative Decomposition ◽  
Material Models ◽  
Continuum Formulation ◽  
Soft Biological Materials

A thermomechanical, polar continuum formulation under finite strains is proposed for anisotropic materials using a multiplicative decomposition of the deformation gradient. First, the kinematics and conservation laws for three-dimensional, polar, and nonpolar continua are obtained. Next, these kinematics and conservation laws are connected to their corresponding counterparts for surface continua, based on Kirchhoff–Love assumptions. Then the shell material models are extracted from three-dimensional material models for finite-temperature problems using established connections. The weak forms are obtained for both three-dimensional nonpolar continua and Kirchhoff–Love shells. These formulations are expressed in tensorial form so that they can be used in both curvilinear and Cartesian coordinates. They can be used to model anisotropic crystals and soft biological materials.

scholarly journals Three-dimensional SAFT imaging for anisotropic materials using photoacoustic microscopy

Ultrasonics ◽  
2019 ◽  
Vol 98 ◽  
pp. 82-87 ◽  
Author(s):  
K. Nakahata ◽  
K. Karakawa ◽  
K. Ogi ◽  
K. Mizukami ◽  
K. Ohira ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Anisotropic Materials ◽  
Photoacoustic Microscopy

Statistical Evaluation of Local Stress and Strain of Three Dimensional Polycrystalline Material at Elevated Temperature

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Osamu Watanabe
Keyword(s):  
Elevated Temperature ◽  
Isotropic Material ◽  
Statistical Evaluation ◽  
Three Dimensional ◽  
Local Stress ◽  
Anisotropic Materials ◽  
Integration Scheme ◽  
Stress And Strain ◽  
Slip Systems ◽  
Statistical Variation

The present paper presents results of numerical simulation for statistical evaluation of stress and strain at elevated temperature from view point of crystal plasticity level by employing a new Voronoi tessellation algorithm in the three dimensional geometry for general grain shape using first order tetrahedron element (four nodes). The elasticity tensors are assumed to include isotropic material and anisotropic material of FCC or BCC crystal using three material constant parameters. The employed finite element formulation is based on the updated Lagrange type expressed in the general form using trapezoidal integration rule in time domain, and the selective numerical integration scheme is used in the present analysis. The obtained numerical examples include the effects of employed finite elements, employed grain aggregate model, grain diameter size, and grain regularity on local stress. The statistical variation around mean value is investigated for the isotropic material and the anisotropic materials having different anisotropy ratio A in elastic range. The inelastic analysis at elevated temperature is also carried out for the anisotropic materials in order to investigate the statistical variation for the anisotropic materials in strain rate effect problem and creep strain program by introducing additional six cubic slip systems into the conventional 12 octahedral slip systems inelastic range.

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