A methodology for predicting probability of detection for ultrasonic testing

2001 ◽  
Author(s):  
William Q. Meeker
Author(s):  
Xiaosong Du ◽  
Leifur Leifsson ◽  
William Meeker ◽  
Praveen Gurrala ◽  
Jiming Song ◽  
...  

Abstract Model-assisted probability of detection (MAPOD) and sensitivity analysis (SA) are important for quantifying the inspection capability of nondestructive testing (NDT) systems. To improve the computational efficiency, this work proposes the use of polynomial chaos expansions (PCEs), integrated with least-angle regression (LARS), a basis-adaptive technique, and a hyperbolic truncation scheme, in lieu of the direct use of the physics-based measurement model in the MAPOD and SA calculations. The proposed method is demonstrated on three ultrasonic testing cases and compared with Monte Carlo sampling (MCS) of the physics model, MCS-based kriging, and the ordinary least-squares (OLS)-based PCE method. The results show that the probability of detection (POD) metrics of interests can be controlled within 1% accuracy relative to using the physics model directly. Comparison with metamodels shows that the LARS-based PCE method can provide up to an order of magnitude improvement in the computational efficiency.


2012 ◽  
Vol 544 ◽  
pp. 72-76
Author(s):  
Jun Zhang ◽  
Hui Ding ◽  
Ming Li ◽  
Guan Bing Ma

Reliability analysis of the procedure of ultrasonic technique before inspection has been proved to be essential to ensure the equipment operation safety. The conventional evaluation methods are based on statistical models and a remarkable sample size is needed to get a accurate result. In this work, the Bootstrap model for small sample data is established based on the re-sampling technique. The probability of detection (POD) curves in different conditions are calculated based on the Bootstrap model, and used for quantitative analysis the influence of inspection parameter on stainless steel auto ultrasonic testing result. The calculated result based on bootstrap model is compared with which based on model assisted POD method. The results indicate that Bootstrap model is an efficient tool for the reliability analysis of inspection with small sample data, and insure the inspection result.


Author(s):  
Pradipta Sarkar ◽  
William Q. Meeker ◽  
R. Bruce Thompson ◽  
Timothy A. Gray ◽  
Warren Junker

2020 ◽  
Vol 17 (2) ◽  
pp. 209
Author(s):  
Jeffry Jamil ◽  
Syed Yusainee Syed Yahya ◽  
Rosnah Zakaria

Non-destructive testing (NDT) is a method of testing and analysis that relies on the application of physical principles to determine the integrity of materials without causing damage. The existence of weld discontinuity can affect the service ability of the structures. Ultrasonic testing Phases Array (UTPA) is advanced ultrasonic testing technology widely practiced in many industries. The multiple ultrasonic elements and electronic time delay will create constructive and destructive interference and steering capability, which could improve detectability compared to a single element of conventional UT. The multi displays presented in A-Scan, S-scan, B-Scan, and C-Scan of UTPA equipment capable of locating, inspecting, and characterise defects within the welded component. Two carbon steel plates with thickness 18 mm and 24 mm were prepared and cut to V-shape configuration and welded using shielded metal arc welding (SMAW) process, labelled as NDE-8826 and NDE-8827 respectively. Both samples were induced with artificial defects of the weld. 16 elements of phased array probe with 0.5 mm pitch and 4 MHz were carried out for this study with encoded scanning to identify weld discontinuity plotted in different types of UT displays. Additional testing was performed using conventional ultrasonic testing (UT) using a 4 MHz probe to compare with the UTPA results and the acceptability of each defect detections. The length and datum of toe crack, slag, and lack of inter run fusion detected by UTPA in NDE-8826 give the same value as the actual value. However, the localisation of the defect is slightly different at 1.0 mm for UT detection. While the detection value for slag gives the same values for UT and UTPA, which also the same as the actual values. The detection of lack of penetration and lack of fusion in sample NDE-8827 was precisely can be detected by UT and UTPA; hence their datum value has slightly different in the centerline crack and porosity at 2.0 mm for UT measurement, and as for UTPA, it was found that the porosity at 3.0 mm which higher value compared to the actual value, 250 mm. From the result, a relevant indication from the UTPA and conventional UT collected it was found that the UTPA technique is capable of improving the Probability of Detection (POD) of defects compared to the conventional UT.


2020 ◽  
pp. 4-17
Author(s):  
V. G. Badalyan

The effectiveness of methods and means of ultrasonic non-destructive control (ultrasonic control) is evaluated by the probability of detecting defects and the reliability of the results of the control. In this work, we reserch the behavior of PoD(a) – the defect detection function, which describes the dependence of the probability of detection of defects on their height, and estimates the reliability of control by means of ROC analysis of the control data. An analysis of the PoD curves obtained by ultrasonic testing with ultrasonic flaw detection and ultrasonic flaw detection instruments demonstrates significantly greater reliability of the use of defectometry techniques and devices. ROC curves constructed using ultrasonic defectometry data make it possible to evaluate the reliability of control of defects of various heights. Analysis of ROC curves provides additional information for optimizing ultrasonic control techniques. The studies were carried out on the data array of ultrasonic testing of welded joints with real cracks.


Author(s):  
D. Shahriari ◽  
A. Zolfaghari ◽  
M. Jahazi ◽  
P. Bocher

Welded structures are examined nondestructively, particularly for critical applications where weld failure can be catastrophic, such as in pressure vessels, load-bearing structural members, and power plants. Ultrasonic Testing (UT) is used in the examination of welds in thinner and thicker gauge materials where the size and location of the flaws are important to detect and interpret. Despite the advantages of the ultrasonic technique, the classification of defects based on ultrasonic signals is still frequently questioned, since the analysis and the identification of defect types depend exclusively on the experience and knowledge of the operator. The problem becomes more acute when high inspection rates, high probability of detection, and low number of false results are required. Thus, the correct classification of the type of flaw present in the material reduces measurement errors, increasing the confidence in the test and consequently the safety of the welded structure during service. In the present study, a new algorithm that allows for the detection and measurement of the length and type of weld defects is proposed. The system is based on a coupled dynamic and static patterns in an A-Scan and uses the defects cited in DIN EN 1713 standard as reference for evaluation. The proposed expert system has been evaluated and validated by examining several specimens containing various types of natural (non-artificial) defects identified in the mentioned standard. The results indicate that, the proposed algorithm has a clear potential in automatic defect detection and presents many advantages to the manual method for defect detection and characterization.


Author(s):  
Dongliang Lu ◽  
Jason Skow ◽  
Sean Keane

The probability of detection (POD) describes the ability of an in-line inspection (ILI) tool to detect cracks and is one of the key performance indicators for ILI system qualification. The POD of an ILI tool is often specified by the vendor as the probability of a feature above a certain threshold size being detected by the tool. To verify the POD performance of ILI tools, selected pipeline sections from the ILI runs are excavated and inspected. The excavation data provide valuable information that can be used to assess the performance that the ILI tool achieved in a field environment. This paper analyzes the performance of an ultrasonic testing (UT) tool in detecting stress corrosion cracking (SCC) features using the ILI run results and excavation data from several operating pipelines. Analysis of the excavation data shows that the POD for SCC features is dependent on both the maximum depth and the longest interacting length of the feature. As the SCC becomes deeper and longer, the POD increases. An analytical POD model is described in which the POD of the UT tool for SCC features is modeled as a function of the maximum depth and the longest interacting length. Parameters of the POD model are estimated using a maximum likelihood method based on the ILI and excavation data. The analytical POD model provides refined means to evaluate the POD performance for SCC features of the tool. The methodology described in this paper can be used for similar analyses of POD performance of other tools or for other types of features.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 47-55
Author(s):  
Takuma Tomizawa ◽  
Haicheng Song ◽  
Noritaka Yusa

This study proposes a probability of detection (POD) model to quantitatively evaluate the capability of eddy current testing to detect flaws on the inner surface of pressure vessels cladded by stainless steel and in the presence of high noise level. Welded plate samples with drill holes were prepared to simulate corrosion that typically appears on the inner surface of large-scale pressure vessels. The signals generated by the drill holes and the noise caused by the weld were examined using eddy current testing. A hit/miss-based POD model with multiple flaw parameters and multiple signal features was proposed to analyze the measured signals. It is shown that the proposed model is able to more reasonably characterize the detectability of eddy current signals compared to conventional models that consider a single signal feature.


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