Probabilistic evaluation of the area of coverage of a probe used for eddy current non-destructive inspections

2020 ◽  
Vol 64 (1-4) ◽  
pp. 11-18
Author(s):  
Noritaka Yusa ◽  
Takuma Tomizawa ◽  
Haicheng Song
Keyword(s):  
Eddy Current ◽  
Gaussian Function ◽  
Probability Of Detection ◽  
Steel Plates ◽  
Detection Model ◽  
Probabilistic Evaluation ◽  
Proposed Model ◽  
Scanning Line ◽  
Non Destructive ◽  
Type 316L Stainless Steel

This study proposes a method to probabilistically evaluate the area of coverage of nondestructive inspections to detect defects on a surface of a structure. For the specific problem, this study considers the effect of the distance between two neighboring scanning lines on the detectability of eddy current testing against near-side cracks. Thirty-eight type 316L stainless steel plates having a fatigue crack were prepared, and eddy current examinations were performed with a sufficiently fine scanning pitch. The full width at half maximum of the spatial distribution of the amplitude of the signals was approximated using a Gaussian function. A probability of detection model considering the distance between two neighboring scanning lines is proposed because in actual inspections a scanning line does not always run directly above a crack. The results demonstrated that the proposed model enables a reasonable probabilistic evaluation of the effect of the distance between two neighboring scanning lines.

A New Approach to Improve the Probability of Detection of Eddy Current Inspection

2013 ◽  
Vol 712-715 ◽  
pp. 2026-2029
Author(s):  
Wu Bo Zhang ◽  
Shu Li Pan ◽  
Ping Jie Huang ◽  
Di Bo Hou ◽  
Guang Xin Zhang
Keyword(s):  
Eddy Current ◽  
Crack Size ◽  
Probability Of Detection ◽  
Metallic Structures ◽  
New Approach ◽  
Eddy Current Inspection ◽  
The Common ◽  
Pod Analysis ◽  
Non Destructive ◽  
Evaluation Techniques

Eddy current testing is now a widely used Non Destructive Test (NDT) method for determining the size of cracks in metallic structures. The probability of detection (POD) is a key metric in assessing the effectiveness of nondestructive evaluation techniques. The POD analysis using common method is studied and modified. The eddy current sensor effective is discussed to support the proposed method. The new method is shown better result in improve the POD than the common one. The estimates of POD as a function of crack size will be valuable for future model-assisted POD study.

Evaluation of detection capability of eddy current probes with stochastic decision threshold for inspecting pits on austenitic stainless steel welding

2021 ◽  
pp. 1-15
Author(s):  
Jing Wang ◽  
Haicheng Song ◽  
Takuma Tomizawa ◽  
Noritaka Yusa ◽  
Yuanjin Ling
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Defect Detection ◽  
Eddy Current ◽  
Probability Of Detection ◽  
Decision Threshold ◽  
The Novel ◽  
Detection Capability ◽  
Stainless Steel Welding ◽  
Proposed Model

It is still a big challenge to calculate the probability of defect detection for inspecting pits on austenitic stainless steel welding using traditional POD models. Because we determine the decision threshold, the POD curve has a lot of changes as the decision threshold changes, there is no clear reason to insist which threshold is reasonable. This study proposes a new probability of detection (POD) model to quantitatively assess the detection capability of eddy current probes for inspecting pits on austenitic stainless steel welding. The experimental results show that the proposed model is more reasonable than traditional ones. The novel POD model was employed to analyze three eddy current probes, uniform, TR, plus-point probes on austenitic stainless steel welding. The results reveal that the uniform eddy current probe has the best detection capability for inspecting pits on among the three probes.

Experimental verification of improved probability of detection model considering the effect of sensor’s location on low frequency electromagnetic monitoring signals

2020 ◽  
Vol 64 (1-4) ◽  
pp. 191-199
Author(s):  
Haicheng Song ◽  
Noritaka Yusa
Keyword(s):  
Monte Carlo Simulation ◽  
Health Monitoring ◽  
Low Frequency ◽  
Probability Of Detection ◽  
Detection Model ◽  
Proposed Model ◽  
Reasonable Approach ◽  
Multiple Defect ◽  
Electromagnetic Monitoring ◽  
Sensor Locations

Structural health monitoring (SHM) is a promising method for maintaining the integrity of structures. A reasonable approach is necessary to quantify its detection uncertainty by taking into account the effect of random sensor locations on inspection signals. Recent studies of the authors proposed a model that adopts Monte Carlo simulation to numerically obtain the distribution of inspection signals influenced by random sensor locations. This model can evaluate the effect not only of multiple defect dimensions but also of the placement of sensors on the detection uncertainty. However, its effectiveness has only been confirmed using pseudo-experimental signals generated by artificial pollution. This study aims to examine the effectiveness of the proposed model in quantifying the detection uncertainty of SHM methods using the experimental signals of low frequency electromagnetic monitoring for inspecting wall thinning in pipes. The results confirm the capability of the proposed model to correctly characterize the distribution of inspection signals affected by random sensor locations and to determine the reasonable probability of detection.

scholarly journals A Study of the Automated Eddy Current Detection of Cracks in Steel Plates

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Ehsan Mohseni ◽  
Hamid Habibzadeh Boukani ◽  
Demartonne Ramos França ◽  
Martin Viens
Keyword(s):  
Eddy Current ◽  
Fatigue Cracks ◽  
Experimental Tests ◽  
Signal Amplitude ◽  
Scanning Speed ◽  
Probability Of Detection ◽  
Steel Plates ◽  
Surface Probe ◽  
Surface Fatigue ◽  
Current Test

AbstractApplying life estimation approaches to determine in-service life of structures and plan the inspection schedules accordingly are becoming acceptable safety design procedures in aerospace. However, these design systems shall be fed with reliable parameters related to material properties, loading conditions and defect characteristics. In this context, the role of non-destructive (NDT) testing reliability is of high importance in detecting and sizing defects. Eddy current test (ECT) is an electromagnetic NDT method frequently used to inspect tiny surface fatigue cracks in sensitive industries. Owing to the new advances in robotic technologies, there is a trend to integrate the ECT into automated systems to perform NDT inspections more efficiently. In fact, ECT can be effectively automated as to increase the coverage, repeatability and scanning speed. The reliability of ECT scanning, however, should be thoroughly investigated and compared to conventional modes of applications to obtain a better understanding of the advantages and shortcomings related to this technique. In this contribution, a series of manual and automated ECT tests are carried out on a set of samples using a split-D reflection differential surface probe. The study investigates the level of noise recorded in each technique and discuss its dependency on different parameters, such as surface roughness and frequency. Afterwards, a description of the effect of crack orientation on ECT signal amplitude is provided through experimental tests and finite element simulations. Finally, the reliability of each ECT technique is investigated by means of probability of detection (POD) curves. POD parameters are then extracted and compared to examine the effect of scanning index, frequency and automation on detection reliability.

Probabilistic evaluation of detection capability of eddy current testing to inspect pitting on a stainless steel clad using multiple signal features

2020 ◽  
Vol 64 (1-4) ◽  
pp. 47-55
Author(s):  
Takuma Tomizawa ◽  
Haicheng Song ◽  
Noritaka Yusa
Keyword(s):  
Stainless Steel ◽  
Eddy Current ◽  
Pressure Vessels ◽  
Eddy Current Testing ◽  
Probability Of Detection ◽  
Current Testing ◽  
Multiple Signal ◽  
Signal Features ◽  
Inner Surface ◽  
Drill Holes

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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