Calibrating and Cross-Sectional Equalizing of the Sensitivity of Ultrasonic Phased Array Inspection of Welds

NDT World ◽  
2016 ◽  
Vol 19 (3) ◽  
pp. 17-27
Author(s):  
Нурматов ◽  
Islam Nurmatov ◽  
Лапидус ◽  
Aleks Lapidus ◽  
Пасси ◽  
...  
Keyword(s):  
Cross Section ◽  
Phased Array ◽  
Flaw Detector ◽  
Practical Implementation ◽  
Flat Bottom ◽  
Entire Cross Section ◽  
Cross Sectional ◽  
Common Reference ◽  
Amplitude Correction ◽  
Ultrasonic Phased Array

Introduction. The approach and practical implementation for the sensitivity calibration and its equalizing within entire insonified cross-section of the material have been presented in the article for 3 most common reference artificial reflectors, namely the flat bottom hole (FBH) situated at parallel to the weld bevel plane, the EDM notch (N), and the side drilled hole (SDH). The method. The issue of inhomogeneous sensitivity over cross-section covered through phased array (PA) sectorial scan plan is due to several factors, which are highlighted and explained. 5 of them are independent on the reference reflector’s shape. In addition the FBH and N reference reflectors are characterized by the strong dependency of the echo amplitude on the angle, under which the ultrasonic wave hits their surface (factor 6, which differs the FBH and N from the omnidirectional SDH). The approach for equalizing the sensitivity over sectorial-scan-insonified cross-section of the material for all types of reference reflectors has been proposed and explained. It is based on the ability of ultrasonic PA flaw detector to implement each pulsing-receiving cycle among the plurality of the scan-plan-forming set of focal laws with individually and independently settled gain and other key settings including Distance Amplitude Correction / Time Corrected Gain (DAC / TCG). The Sonotron NDT’s ISONIC Series PA instruments (ISONIC 3510, ISONIC 2010, and ISONIC 2009 UPA Scope) are featured with the said ability uniquely: in the said units the DAC / TCG mechanism is used purely for compensating the dependency of echo amplitude on the material travel distance while the feature of varying Gain per Focal Law is utilized just for the forming of easy-reproducible Angle Gain Compensation (AGC) plan. Both the DAC / TCG and AGC plans are created independently on each other with use of the same reference reflectors. The results. Combining of the independent DAC / TCG and AGC mechanisms for the first time ever provides the equalizing of the sensitivity for all types of reference reflectors independently on their X, Y position over the entire cross-section of the material — this is confirmed by a number of experimental results presented. Conclusion. At last the single group sectorial scan only becomes sufficient for the complete coverage of the whole cross-section of the weld. This allows reducing the dimensions of required PA probes and wedges in use and the width of the area for the scanning along the fusion line. And finally this increases the maximal possible speed of scanning along with reducing of the inspection cost.

Velocity Field and Energy Dissipation in Viscoplastic Flow in Tubes of Non-Circular Cross-Section

2014 ◽  
Author(s):  
Mario F. Letelier ◽  
Dennis A. Siginer ◽  
Felipe Godoy
Keyword(s):  
Energy Dissipation ◽  
Velocity Field ◽  
Yield Stress ◽  
Cross Section ◽  
Mechanical Energy ◽  
Longitudinal Velocity ◽  
Circular Cross Section ◽  
Viscoplastic Flow ◽  
Entire Cross Section ◽  
Cross Sectional

An analytical method for determining the velocity field, shear stress and energy dissipation in viscoplastic flow in non-circular straight tubes is presented. Bingham’s model of fluid is used for the case of tubes with several cross-sectional contours that can be arbitrarily chosen through a shape factor imposed in the solution for the longitudinal velocity. The analysis is extended to steady flow in tubes in which the cross-section contour exhibits sharp corners. In these cases three flow zones are distinguished: stagnant, non-zero deformation, and plug zones. The method provides the expressions for determining the boundaries and characteristics of those three zones for a wide variety of cross-section shapes. In particular the dynamics of plug-zones for large values of the yield stress and for contours that markedly differ from circumferences is analyzed. Energy dissipation is determined throughout the entire cross-section, so that the effect of shape on mechanical energy loss is assessed in terms of the yield stress and viscosity of the fluid. Some general expressions that help understand energy dissipation mechanisms are derived by using natural coordinates for the velocity field and related variables. These results draw on several recent works from other researchers and the present authors, which have highlighted the significant difficulty of determining the zones of zero deformation in viscoplastic flow when the related solid boundaries are not elementary.

scholarly journals Accounting Comparability and the Accuracy of Peer-Based Valuation Models

2015 ◽  
Vol 90 (6) ◽  
pp. 2571-2601 ◽  
Author(s):  
Steven Young ◽  
Yachang Zeng
Keyword(s):  
Cross Section ◽  
Foreign Firms ◽  
Future Market ◽  
Entire Cross Section ◽  
Cross Sectional ◽  
Cross Border ◽  
Multiple Method ◽  
Empirical Tests ◽  
Accounting Comparability ◽  
Sample Window

ABSTRACT We examine the link between enhanced accounting comparability and the valuation performance of pricing multiples. Using the warranted multiple method proposed by Bhojraj and Lee (2002), we demonstrate how enhanced accounting comparability leads to better peer-based valuation performance. Empirical tests using firms from 15 European Union (EU) countries over the period 1997–2011 (with comparable peers selected from the entire cross-section of foreign firms) document significant improvement in valuation performance measured as pricing accuracy, the ability of value estimates to explain cross-sectional variation in observed price, and the ability of the pricing multiple to predict future market-to-book multiples. Findings for a series of identification tests suggest that enhanced valuation performance is the consequence of improvements in the degree of cross-border accounting comparability that occurred during the sample window, and that a significant fraction of comparability gain operates through improved peer selection.

On-Line Phased-Array Ultrasonic System: OPUS to Control Pressure Sheath of Flexible Pipe During Manufacturing

2016 ◽  
Author(s):  
Mickaël Mélot ◽  
Julien Berthon
Keyword(s):  
Phased Array ◽  
Ultrasonic Waves ◽  
Quality Level ◽  
Flexible Pipe ◽  
Operation Condition ◽  
Cross Sectional ◽  
Flexible Pipes ◽  
Internal Fluid ◽  
Ultrasonic Phased Array ◽  
On Line

Flexible pipes are made up of several different layers specifically designed to meet the requirements of our clients and API17J / ISO13628-2. In the pursuit of ever more efficient and reliable solutions, even in the world’s harshest and deepest offshore environments, TECHNIP’s R&D activity is focused on extending its product range by introducing new products and materials. As part of this innovation program, new polymers are constantly being investigated to assess their potential as a pressure sheath. The pressure sheath is the most critical thermoplastic sheath within the structure. Its role is to contain internal fluid and transfer internal pressure to the pressure vault layer outside it. To fulfill that mission, this polymer must be leakproof and perform over wide temperature and pressure range. In operation condition, the presence of small flaws within the pressure sheath could propagate leading to failure and significant environmental and operational damages. Therefore, the manufacturing of such a polymer layer must conform with ever-higher levels of reliability and quality. This is the reason why a visual inspection of pressure sheath according to API17J / ISO13628-2 standards is mandatory. As a leitmotiv, TECHNIP dedicates a lot of effort, not only to extend the limits of the possible by introducing new materials, but also to take inspection further beyond standard requirements by developing dedicated on-line NDT control systems able to ensure layer high quality. Many people are familiar with the medical applications of ultrasonic imaging in which ultrasonic waves are used to create highly detailed cross-sectional pictures of internal organ. Medical echography is commonly performed with specialized multielement probe known as phased-array and their accompanying hardware and software. The applications of ultrasonic phased-array technology are not limited to medical diagnosis and in recent years, increasing use of these systems can be observed in industrial environment. Nevertheless, although phased-array systems on the market can provide new levels of information and visualization, they are manually and locally operated and are inappropriate to control polymer sheath over several kilometers during manufacturing. This paper presents a specific and automated ultrasonic system dedicated to manufacturing control of thermoplastics such as the pressure sheath. Developed by TECHNIP, and based on cutting edge ultrasonic technology used in aerospace and medicine, OPUS is a world-class NDT system able to prove that our pressure sheaths meet design criteria and achieve the highest quality level.

Sandwich Beam Analysis

1972 ◽  
Vol 39 (3) ◽  
pp. 773-778 ◽  
Author(s):  
D. Krajcinovic
Keyword(s):  
Cross Section ◽  
Static Load ◽  
Sandwich Beam ◽  
Beam Theory ◽  
Simple Algebra ◽  
Sandwich Beams ◽  
Consistent Theory ◽  
Entire Cross Section ◽  
Cross Sectional ◽  
Beam Analysis

A consistent theory of sandwich beams subjected to static load is presented. The theory is developed under the assumption that the Bernoulli’s hypothesis is valid for each lamina independently but not for the entire cross section as a whole. It is shown that the generalized displacement may be chosen in such a way that the set of equations governing the motions for which the beam remains straight on one, and a set of equations describing bending and shear types of motions on the other hand are independent. Furthermore, after some simple algebra, separate equations for each generalized displacement are derived. The normal stress is given in the from which is familiar from strength of materials with two additional terms embodying the influence of the cross-sectional distortion (deviation from classical beam theory).

Inner Detection of Corrosion by Ultrasonic Phased Array in Underground Compressed Natural Gas Storage Well

2016 ◽  
Author(s):  
Cunjian Miao ◽  
Weican Guo ◽  
Zhangwei Ling ◽  
Ping Tang
Keyword(s):  
Natural Gas ◽  
Ultrasonic Testing ◽  
Phased Array ◽  
Testing System ◽  
Ultrasonic Frequency ◽  
General Corrosion ◽  
Entire Cross Section ◽  
Compressed Natural Gas ◽  
Corrosion Condition ◽  
Ultrasonic Phased Array

Compressed natural gas (CNG) storage well is a kind of pressure vessel buried underground. The detection of corrosion, which may be induced by the surrounding soil and different medium, is important for the safety security of the well, and protects it from CNG leakage or casing explosion. Among non-destructive examination techniques for corrosion detecting, the ultrasonic techniques are popularly utilized, in which the phased array approach can offer distinct advantages. To investigate both reliability and applicability of the phased array technique in the storage well, a complex design with a 512-element ultrasonic phased array that covered the entire cross-section was discussed, and phased array parameters were determined, including array elements, array element size, ultrasonic frequency and so on. An ultrasonic testing system was designed based on the above design, including a frame for holding phased array probes, a specific vessel for storing ultrasonic cards and other components, and an in-pipe robot designed for instruments’ moving in the storage well. The general corrosion condition described by thickness images were captured by the ultrasonic testing system with B, C and D-scan functions, in which circumferential electronic linear scanning was performed by the phased array probes and axial scanning was done by a mechanical scanning device. A method for minimizing the external pressure from water column necessary for coupling was put forward in the scanning and detection process. The sample for CNG storage well with artificial defects was built in laboratory environments and experiments were conducted to validate detection effects, and the phased array technique provided good sensitivity and efficiency, which may lead to a successful application in CNG storage well examination.

scholarly journals Application of Dual Focused Ultrasonic Phased Array Transducer in Two Orthogonal Cross-Sections for Inspection of Multi-Layered Composite Components of the Aircraft Fuselage

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1689 ◽  
Author(s):  
Renaldas Raišutis ◽  
Olgirdas Tumšys
Keyword(s):  
Spatial Resolution ◽  
Cross Sections ◽  
Phased Array ◽  
Complex Geometry ◽  
Ultrasonic Waves ◽  
Internal Defect ◽  
Flat Bottom ◽  
Aircraft Fuselage ◽  
Array Transducer ◽  
Ultrasonic Phased Array

Our previous studies have shown that the application of the proposed technique of a dual focused ultrasonic beam in two orthogonal cross-sections in passive (elevation) and active (azimuth) apertures of linear ultrasonic phased array transducer (ULPAT) enhances the 3D spatial resolution in the case of the inspection of conventional defects (flat bottom holes) or measurement of thickness of multi-layered metal composites. The objective of this work is to apply the proposed technique to enhance the spatial resolution of the ULPAT in the cases of detection and sizing demonstration of internal defects possessing spatially complex geometry, and during the inspection of defective multi-layered thin composite components (e.g., GLARE) of the aircraft fuselage. The specially prepared aluminium specimen possessing an internal defect of complicated geometry (crescent-shaped) was investigated. The simulation results and experiments demonstrate the resolution enhancement, higher amplitude of the reflections (e.g., 2.5 times or +8 dB) and spatial improvement in the defect detection even in the case of the non-perpendicular incidence of ultrasonic waves to the complex geometry surface of the internal defect. During the experiments, the multi-layered GFRP-metal based composite sample GLARE 3-3/2 was investigated in the case of the single-side access to the surface of the sample. The internal artificial delamination type defect of 25 mm was detected with a higher accuracy. Compared to the limitations of conventional ULPAT, the relative error (32%) (at the −6 dB level) of lateral defect dimensions estimation was completely reduced.

A Model to Predict Phased Array Ultrasonic Testing Signals from a Flat-Bottomed Hole in Two Medium

2006 ◽  
Vol 321-323 ◽  
pp. 501-504 ◽  
Author(s):  
Sung Jin Song ◽  
Joon Soo Park ◽  
Hak Joon Kim ◽  
Un Hak Seong ◽  
Suk Chull Kang ◽  
...  
Keyword(s):  
Phased Array ◽  
Steel Specimen ◽  
Measurement Model ◽  
Beam Model ◽  
Flat Bottom ◽  
Ultrasonic Signals ◽  
Array Transducer ◽  
Ultrasonic Phased Array ◽  
Set Up ◽  
Pulse Echo

In this study, the expanded multi-Gaussian beam model is adopted to develop a model to calculate the ultrasonic beam fields radiated from an ultrasonic phased array transducer. Combining this beam model with three other components including time delays, a far-field scattering model and a system efficiency factor, we develop a complete ultrasonic measurement model for predicting the phased array ultrasonic signals that can be captured from a flat-bottom hole in a steel specimen in a pulse-echo set-up using an array transducer mounted in a solid wedge. This paper describes the complete model developed with its key ingredients.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 70-71
Author(s):  
Brian L. Rhoades
Keyword(s):  
Cross Section ◽  
Reaction Chamber ◽  
Objective Lens ◽  
Reduced Cross Section ◽  
Cross Sectional ◽  
Structural Investigations ◽  
Transmission Electron ◽  
Dynamic Experiments ◽  
Successful Design ◽  
Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

Sign in / Sign up

Export Citation Format

Share Document