Improved Imaging of Fatigue Crack Profile in Thick Cruciform Samples Using Ultrasonic Phased Array Models

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
S. Alavudeen ◽  
C. V. Krishnamurthy ◽  
Krishnan Balasubramaniam ◽  
D. M. Pugazhendhi ◽  
G. Raghava ◽  
...  
Keyword(s):  
Phased Array ◽  
Fatigue Cracks ◽  
Crack Depth ◽  
Potential Drop ◽  
Subzero Temperature ◽  
Virtual Experiments ◽  
Physical Measurements ◽  
Ultrasonic Phased Array ◽  
Experimental Trials

The determination of depth profile of vertical fatigue cracks generated in thick cruciform samples using an ultrasonic phased array is investigated in this paper. The cracks were formed by conducting fatigue fracture test on two mild steel cruciform specimens of 135 mm thickness: one under room temperature and the other under subzero temperature (−70°C). A semi-elliptical surface starter notch of 2 mm width and more than 400 mm length was initially created in the specimens. Alternating current potential drop technique and phased array ultrasonic technique were attempted in order to determine the depth profiles of the starter notch as well as that of the crack. Virtual experiments carried out with a finite-difference time domain based numerical model were found to be advantageous in reducing actual experimental trials, facilitate an understanding of the echo signatures, and help assess the crack depth. The profiles of the crack and the notch were verified through destructive assay of the samples and subsequent dye penetrant assisted physical measurements.

Production of Realistic Flaws and Their Meaning for Ultrasonic Testing

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
Jiri Hodac ◽  
Pavel Mares ◽  
Jaromir Janousek ◽  
Martin Linhart
Keyword(s):  
Staff Training ◽  
Ultrasonic Testing ◽  
Phased Array ◽  
Fatigue Cracks ◽  
Ultrasonic Test ◽  
P 75 ◽  
Array Technology ◽  
Ultrasonic Echo ◽  
Ultrasonic Phased Array ◽  
Test Result

This work is designed to artificially create test specimens with flaws that behave the same way as real-function flaws when observed by nondestructive testing (NDT) technologies. Thus, the understanding of the detection limitations of NDT methods is needed. In this study, real, realistic, and artificial flaws were compared by ultrasonic phased array technology. Fatigue flaws, which belong to the most common structural issues (Ruzicka, M., Hanke, M., and Rost, M., 1987, Dynamicka Pevnost a Zivotnost, CVUT, Prague, Czech Republic, p. 75), are investigated. Measurements have revealed significant differences in the amplitude of ultrasonic echo from fatigue cracks in distinct phases of crack propagation. Studied specimens with realistic flaws have demonstrated their quality for calibration, staff training, and NDT system qualification. More realistic test specimens will increase ultrasonic test result reliability.

The Quantification Research of Engine Body Defect that Tested by Ultrasonic Phased Array

2014 ◽  
Vol 494-495 ◽  
pp. 73-77
Author(s):  
Ding Bang Ma
Keyword(s):  
Nondestructive Testing ◽  
Phased Array ◽  
Fatigue Cracks ◽  
The Body ◽  
Testing Equipment ◽  
Ultrasonic Nondestructive Testing ◽  
Long Run ◽  
Ultrasonic Phased Array ◽  
Ultrasonic Emission ◽  
Array Detection

After a long run, the places of body cooperate with valve very easy to produce fatigue cracks. This cracks if not detected, extremely easy to have the accident. As the most commonly used testing equipment, ultrasonic nondestructive testing is often used to detect the engine body. However, most of the existing ultrasonic nondestructive testing equipment is used to detect whether there is a defect, there is little research the specific size of defects. According to the principle of ultrasonic emission, theoretical calculation and combined with test block, get the body phased array detection method.

Application of Ultrasonic Phased Array Techniques for Inspection of Stud Bolts in Nuclear Power Plants

2006 ◽  
Vol 110 ◽  
pp. 97-104 ◽  
Author(s):  
Sang Woo Choi ◽  
Joon Hyun Lee
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Phased Array ◽  
Nuclear Reactor ◽  
Fatigue Cracks ◽  
Ultrasonic Inspection ◽  
Phased Array Techniques ◽  
Ultrasonic Phased Array ◽  
Ultrasonic Images

The reactor vessel body and closure head are fastened with the stud bolt that is one of crucial parts for safety of the reactor vessels in nuclear power plants. It is reported that the stud bolt is often experienced by fatigue cracks initiated at threads. Stud bolts are inspected by the ultrasonic technique during the overhaul periodically for the prevention of failure which leads to radioactive leakage from the nuclear reactor. The conventional ultrasonic inspection for stud bolts was mainly conducted by reflected echo method based on shadow effect. However, in this technique, there were numerous spurious signals reflected from every oblique surfaces of the thread. In this study, ultrasonic phased array technique was applied to investigate detectability of flaws in stud bolts and characteristics of ultrasonic images corresponding to different scanning methods, that is, sector and linear scan. For this purpose, simplified stud bolt specimens with artificial defects of various depths were prepared.

An Ultrasonic Phased Array Evaluation of Cast Austenitic Stainless Steel Pressurizer Surge Line Piping Welds

2010 ◽  
Author(s):  
Aaron A. Diaz ◽  
Anthony D. Cinson ◽  
Susan L. Crawford ◽  
Traci L. Moran ◽  
Michael T. Anderson
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Ultrasonic Testing ◽  
Phased Array ◽  
Fatigue Cracks ◽  
Ultrasonic Beam ◽  
Custom Made ◽  
Ultrasonic Phased Array ◽  
Surge Line ◽  
Thermal Fatigue Cracks

A set of circumferentially oriented thermal fatigue cracks (TFCs) were implanted into three cast austenitic stainless steel (CASS) pressurizer (PZR) surge-line specimens (pipe-to-elbow welds) that were fabricated using vintage CASS materials formed in the 1970s, and flaw responses from these cracks were used to evaluate detection and sizing performance of the phased-array (PA) ultrasonic testing (UT) methods applied. Four different custom-made PA probes were employed in this study, operating nominally at 800 kHz, 1.0 MHz, 1.5 MHz, and 2.0 MHz center frequencies. The CASS PZR surge-line specimens were polished and chemically etched to bring out the microstructures of both pipe and elbow segments. Additional studies were conducted and documented to address baseline CASS material noise and observe possible ultrasonic beam redirection phenomena.

scholarly journals Effect of the Material Structure on the Noise Level in Phased Array Ultrasonic Tests

2020 ◽  
pp. 57-65
Author(s):  
Karol Kaczmarek ◽  
Leszek Grolik
Keyword(s):  
Noise Level ◽  
Phased Array ◽  
Material Structure ◽  
Test Results ◽  
Test Configuration ◽  
Treatment Processes ◽  
Ultrasonic Phased Array ◽  
Steel Grades ◽  
Low Amplitude

The article presents results of tests performed to determine the noise level in ultrasonic Phased Array testing. The tests, involving non-alloy steel S355 and austenitic steel X5CrNi18-10, were carried out applying a frequently used test configuration and 16-element 5 MHz array probes having an aperture of 10 mm ×10 mm. The obtainment of a differentiated structure, i.e. characterised by various grain sizes, required the performance of special heat treatment processes. Metallographic tests, concerning both steel grades, were performed to quantify the grain size. Specimens containing artificially made SDH Ø3 cylindrical reflectors and spherical reflectors having various diameters were made of the material prepared in the above-presented manner. The tests also involved amplitude measurements and the identification of the noise level of the reflectors. The test results enabled the quantitative determination of the signal-noise ratio, affecting the detection of low-amplitude indications.

Ultrasonic Phased Array Evaluations of Implanted and In-Situ Grown Flaws in Cast Austenitic Stainless Steel Pressurizer Surge Line Piping

2011 ◽  
Author(s):  
Susan L. Crawford ◽  
Anthony D. Cinson ◽  
Traci L. Moran ◽  
Matthew S. Prowant ◽  
Aaron A. Diaz ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Phased Array ◽  
Fatigue Cracks ◽  
Base Material ◽  
Pacific Northwest National Laboratory ◽  
Asme Code ◽  
Ultrasonic Phased Array ◽  
Surge Line

A set of circumferentially oriented thermal fatigue cracks (TFCs) were implanted into three cast austenitic stainless steel (CASS) pressurizer (PZR) surge-line specimen welds (pipe-to-elbow configuration) that were salvaged from a U.S. commercial nuclear power plant that had not been operated. Thus, these welds were fabricated using vintage CASS materials that were formed in the 1970s. Additionally, in-situ grown TFCs were placed in the adjacent CASS base material of one of these specimens. Ultrasonic phased-array responses from both types of flaws (implanted and in-situ grown) were analyzed for detection and characterization based on sizing and signal-to-noise determination. Multiple probes were employed covering the 0.8 to 2.0 MHz frequency range. To further validate the Pacific Northwest National Laboratory (PNNL) findings, an independent in-service inspection (ISI) supplier evaluated the flaws with their American Society of Mechanical Engineers (ASME) Code, Section XI, Appendix VIII-qualified procedure. The results obtained by PNNL personnel compared favorably to the ISI supplier results. All examined flaws were detected and sized within the ASME Code-allowable limits.

An Improved Quantitative Image Analyser

1977 ◽  
Vol 35 ◽  
pp. 226-227
Author(s):  
J.P. Fallon ◽  
P.J. Gregory ◽  
C.J. Taylor
Keyword(s):  
Feature Extraction ◽  
Quantitative Analysis ◽  
Frequency Content ◽  
General Sense ◽  
Physical Measurements ◽  
Quantitative Image ◽  
Image Analyser ◽  
Automatic Methods ◽  
Quantitative Results

Quantitative image analysis systems have been used for several years in research and quality control applications in various fields including metallurgy and medicine. The technique has been applied as an extension of subjective microscopy to problems requiring quantitative results and which are amenable to automatic methods of interpretation.Feature extraction. In the most general sense, a feature can be defined as a portion of the image which differs in some consistent way from the background. A feature may be characterized by the density difference between itself and the background, by an edge gradient, or by the spatial frequency content (texture) within its boundaries. The task of feature extraction includes recognition of features and encoding of the associated information for quantitative analysis.Quantitative Analysis. Quantitative analysis is the determination of one or more physical measurements of each feature. These measurements may be straightforward ones such as area, length, or perimeter, or more complex stereological measurements such as convex perimeter or Feret's diameter.

Scanning-probe microscope analysis of optical thin films: A new analytical tool in a manufacturing environment

1994 ◽  
Vol 52 ◽  
pp. 1068-1069
Author(s):  
S. P. Sapers ◽  
R. Clark ◽  
P. Somerville
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Control ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
List Type ◽  
Manufacturing Environment ◽  
Physical Measurements ◽  
Probe Microscope

OCLI is a leading manufacturer of thin films for optical and thermal control applications. The determination of thin film and substrate topography can be a powerful way to obtain information for deposition process design and control, and about the final thin film device properties. At OCLI we use a scanning probe microscope (SPM) in the analytical lab to obtain qualitative and quantitative data about thin film and substrate surfaces for applications in production and research and development. This manufacturing environment requires a rapid response, and a large degree of flexibility, which poses special challenges for this emerging technology. The types of information the SPM provides can be broken into three categories:(1)Imaging of surface topography for visualization purposes, especially for samples that are not SEM compatible due to size or material constraints;(2)Examination of sample surface features to make physical measurements such as surface roughness, lateral feature spacing, grain size, and surface area;(3)Determination of physical properties such as surface compliance, i.e. “hardness”, surface frictional forces, surface electrical properties.

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