| 1. |
- Hammersberg, Peter, 1961, et al.
(författare)
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EMULATION OF POD CURVES FROM SYNTHETIC DATA OF PHASED ARRAY ULTRASOUND TESTING
- 2012
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Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 1430:31, s. 937-944
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Konferensbidrag (refereegranskat)abstract
- Reliability of non-destructive techniques (NDT) is traditionally quantified byexperimental determined probability of detection (POD). Such multi-parameter variability studies require a significant amount of experiments for each application verified, making them extremely costly. Reducing the need of experimental data by simulations requires both a verified simulation model and a procedure for effective computer experiments. Here synthetic POD curves for ultrasonic phased array testing have been generated using simSUNDT for signal amplitude simulations and a procedure to emulate response variability by predictive (meta) modeling and Monte Carlo simulations.
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| 2. |
- Hammersberg, Peter, 1961, et al.
(författare)
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The Potential in Simulation and Metamodeling for the Understanding and Development of NDE
- 2014
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Ingår i: Materialpruefung/Materials Testing. - : Walter de Gruyter GmbH. - 0025-5300 .- 2195-8572. ; 56:11-12, s. 980-987
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Tidskriftsartikel (refereegranskat)abstract
- By combining detailed mathematical modeling of the physics involved in NDE with a broader and robust engineering approach based on the sequential steps of screening, modeling and optimization, it is possible to generate metamodels that can support NDE engineering efforts to evaluate the applicability of NDE in a wider context, as a complement to the repeatability, reproducibility and capability studies normally performed. The aim of the initial screening phase is to effectively evaluate and prioritize NDE control parameters from a wider perspective regarding the demands of a specific application and to prioritize parameters of lesser importance for the outcome on the basis of economic and practical considerations. The aim of the second and third steps is to study the influence of the important parameters and to perform sensitivity analyses of reproducibility and repeatability, for example, followed by procedure development, respectively. The methodology is straightforward when it comes to smooth response surfaces of lower order (up to second or third order). Generally, the recommendation for the screening phase is 'to be bold' for the definition of the experimental range for each parameter - meaning to make them as wide as possibly relevant for the specific application. For NDE applications not following the Berens assumption for POD studies, e. g., large cracks yield large response signals, such as the varying signal amplitudes from surface breaking notches in ultrasonic testing, the mentioned recommendation of. be-bold. screening phase may lead to incorrect prioritization of parameters. In this publication, this is illustrated by how the width of the experimental range for the control parameters tested during screening actually influences the screening results. Two basic ultrasonic testing set-ups have been compared using the SimSUNDT simulation software package: surface breaking notch (SBN) and side drilled hole (SDH). Even though the results were anticipated, they pointed out the need to further develop the screening methodology supporting NDE engineering, especially when it comes to addressing the issue of applicability. Does the data collected tell us what we actually want to know about the tested application? Or does it only tell us something about the NDE method?
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| 3. |
- Hammersberg, Peter, 1961, et al.
(författare)
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The Potential in Simulations and Meta- Modelling for Understanding and Development of NDE
- 2013
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Ingår i: 5th European-American Workshop on Reliability of NDE.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- By combining detailed mathematical modelling of the physics in NDE with a broader robust engineering approach based on the sequential steps: screening, modelling and optimization, it would be possible to generate meta-models that can support the NDE Engineering efforts to evaluate NDE applicability in a wider context, as a complement before the repeatability, reproducibility and capabilitystudies normally performed. The aim with the initial screening phase is to effectively evaluate and priorities NDE control parameters from a wider perspective relative the demand in the specific application and to fix parameters of less impact on the output response to their most economical and practical level. The aim with the second and third steps is to study how the important parameters influence and to perform sensitivity analysis of reproducibility and repeatability, for example,followed by procedure development, respectively. The methodology is straightforward when it comes to smooth response surfaces of lower order (up to second or third). The recommendation for the screening phase generally is ‘to be bold’ when it comes to the definition of the experimental range for each parameter – meaning make them as wide as possible relevant for the specific application. For NDE applications not following the Berens assumption for POD studies: large cracks yield large response signal. Such as, the varying signal amplitude from surface breaking notches in ultrasonic testing, for example. The be-bold-screening recommendation may lead to incorrect prioritization of parameters. In this paper this is illustrated by how the width of the experimental range for the control parameters tested during screening actually influence the screening result. Two basic ultrasonictesting set-ups have been compared using the SimSUNDT simulation software package: Surface Breaking Notch (SBN) and Side Drilled Hole (SDH). Even though the result was expected. It points out the need of development of the screening methodology supporting the NDE engineering, when it comes to addressing the applicability issue: does the data collected tell us what we actually want to knowabout the tested application (or does it only tell us something of the NDE method).
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| 4. |
- Liu, Qingwei, 1970, et al.
(författare)
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A Receiver Model for Ultrasonic Ray Tracing in an Inhomogeneous Anisotropic Weld
- 2014
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Ingår i: Journal of Modern Physics. - : Scientific Research Publishing, Inc.. - 2153-120X .- 2153-1196. ; 5:13, s. 1186-1201
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a receiver model for ultrasonic ray tracing simulation is described. This is a complementarypart of an existing simulation model and is the next step towards a numerical solutionto the inverse problem and thus a NDT methodology for characterization of the dendrite orientationin a weld. The establishment of the receiver model is based on the electromechanical reciprocityprinciple. A concise retrospect of the weld model and the 2D model is made. The reciprocityprinciple is applied in an original way to handle the model problem including the back wall.Experimental qualitative validations for both P and SV waves on a specific weld are also made forC-scans included in this paper. Two different cases are studied. The first is a direct incidence of anultrasonic ray towards the weld, and the second is a reflection from the back surface in the basematerial followed by an incidence to the weld. Even though mode-converted rays are excluded inthe simulations, both the P and SV probe-models show the same behavior as the experimental results.The qualitative validation though reveals that it even if a thorough time-gating of receivedinformation would enable exclusion of mode-conversion in the model, inaccuracy of experimentalresults is affecting the evaluation of the weld model.
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| 5. |
- Persson, Gert, 1963, et al.
(författare)
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POD GENERATED BY MONTE CARLO SIMULATION USING A META-MODEL BASED ON THE simSUNDT SOFTWARE
- 2012
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Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 2011:31, s. 1773-1780
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Konferensbidrag (refereegranskat)abstract
- A recent developed numerical procedure for simulation of POD is used to identify the most influential parameters and test the effect of their interaction and variability with different statistical distributions. With a multi-parameter prediction model, based on the NDT simulation software simSUNDT, a qualified ultrasonic procedure of personnel within Swedish nuclear power plants is investigated. The stochastical computations are compared to experimentally based POD and conclusions are drawn for both fatigue and stress corrosion cracks.
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| 6. |
- Persson, Gert, 1963, et al.
(författare)
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Recent survey and application of the simSUNDT software
- 2010
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Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. - 9780735407480 ; 1211, s. 2125-2132
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Konferensbidrag (refereegranskat)abstract
- The simSUNDT software is based on a previous developed program (SUNDT). The latest version has been customized in order to generate realistic synthetic data (including a grain noise model), compatible with a number of off-line analysis software. The software consists of a Windows®-based preprocessor and postprocessor together with a mathematical kernel (UTDefect), dealing with the actual mathematical modeling. The model employs various integral transforms and integral equation and enables simulations of the entire ultrasonic testing situation. The model is completely three-dimensional though the simulated component is two-dimensional, bounded by the scanning surface and a planar back surface as an option. It is of great importance that inspection methods that are applied are proper validated and that their capability of detection of cracks and defects are quantified. In order to achieve this, statistical methods such as Probability of Detection (POD) often are applied, with the ambition to estimate the detectability as a function of defect size. Despite the fact that the proposed procedure with the utilization of test pieces is very expensive, it also tends to introduce a number of possible misalignments between the actual NDT situation that is to be performed and the proposed experimental simulation. The presentation will describe the developed model that will enable simulation of a phased array NDT inspection and the ambition to use this simulation software to generate POD information. The paper also includes the most recent developments of the model including some initial experimental validation of the phased array probe model. © 2010 American Institute of Physics.
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| 7. |
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| 8. |
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| 9. |
- Rosell, Anders, 1981, et al.
(författare)
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Estimating Probability of Detection Curves Related to Eddy Current Sender – Receiver Probes
- 2013
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Ingår i: Proceedings of the 5th European-American Workshop on Reliability of NDE.
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Konferensbidrag (refereegranskat)abstract
- Sender – receiver probes are commonly used in eddy current procedures for crack detection. Such probes can give a non-linear signal response as a function of the crack size. Classical methods used for analysis in probability of detection (POD) assessments require that the signal response versus crack size can be predicted with a linear relation, which also must show a constant variance of the collected data points. One approach which can be used to overcome these limitations is to use a mathematical model of the eddy current probe – flaw interaction and use this to estimate the detection probability at specific crack sizes. This method is applied within this work, using the finite element method for the eddy current signal response predictions. In order to manage a large number of calculations at several crack sizes we propose the use of a meta-model approach. A linear meta-model is created at different crack sizes and then used for POD estimation. The number of signal responses above the detection level at specific crack sizes is then used to estimate the POD, a method which does not require any particular relation between signal response and crack size. The meta-model enables a large number of stochastic computations to be carried out in order to estimate the signal response distribution for a specific crack size. We conclude that modelling is a vital part of procedure capability estimations of eddy current procedures based on sender – receiver probe characteristics and can be used for procedure understanding, improvements and aid in experimental verifications.
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| 10. |
- Semenova, Maria, 1992, et al.
(författare)
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Comparison between three mathematical models of three well defined ultrasonic NDT cases
- 2020
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Ingår i: IOP Conference Series: Materials Science and Engineering. - 1757-8981 .- 1757-899X. ; 747:1
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Konferensbidrag (refereegranskat)abstract
- Ultrasonic nondestructive testing (NDT) is commonly used for in-service inspection in different areas. But reliability of NDT method is highly dependent on the equipment and crack features. Although, it is possible to use thoroughly validated mathematical models to avoid complicated and costly experimental work, when it is necessary to qualify new procedures. Finite Element Model (FEM) is a powerful tool, which is commonly used for such cases. In this paper three mathematical models of three well defined cases will be compared with each other.
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