October 7, 2013
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| 13:00 |
Opening |
| 13:30
(close)
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Keynote Presentations |
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| Session chair: |
U. Ewert, DGZfP-Fachausschuss Durchstrahlungsprüfung, Berlin, Germany |
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L. Schaefer, Blue Origin, Kent, USA |
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1
13:30
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A Path Forward for NDE Reliability
W.D. Rummel, D & W Enterprises, Littleton, USA
Abstract:
Nondestructive Evaluation (NDE) is an essential element in modern industry and to advanced technolo...
more
Abstract: minimize
Nondestructive Evaluation (NDE) is an essential element in modern industry and to advanced technology challenges. The NDE role is diverse and ranges from quality assurance of products and systems produced to critical roles in risk analysis and structure integrity assurance in the life cycle management of modern structures and systems. The development and application of fracture mechanics was a revolution in the role and requirements for NDE applications. NDE technology knowledge and practices were challenged to provide quantified detection capabilities and supporting data for specific applications. I led a team to provide detection capabilities data for NDE procedures intended for application to the National Aeronautics and Space Administration (NASA), Space Shuttle. The metric and data developed were the origin of “Probability of Detection – POD”. POD is now recognized and used throughout the world as a tool for quantifying NDE capability assessment and for support of NDE reliability advancements.
Previous workshops have addressed understanding NDE variables in detection, data collection and measurement analysis procedures, and alternative methods of estimating detection capabilities and applications including model assisted POD. A suggested path forward includes development of an NDE engineering protocol and a formalized protocol for “calibration” of NDE measurement tools. Requirements for “calibration” and validation of sensors for various applications includes sensors for “Structural Health Monitoring”
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2
14:10
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A Plenary View on the Vigor of our NDE Reliability Models
C. Müller, BAM, Berlin, Germany
D. Kanzler, Applied Validation of NDT, Berlin, Germany
M. Skender, BAM, Berlin, Germany
M. Bertovic, Berlin, Germany
R. Holstein, DGZfP Ausbildung und Training, Berlin, Germany
J. Pitkänen, Posiva, Eurajoki, Finland
U. Ronneteg, SKB, Oskarshamn, Sweden
Abstract:
Using the Modular Reliability Model the three different main influencing elements, i.e. intrinsic ...
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Abstract: minimize
Using the Modular Reliability Model the three different main influencing elements, i.e. intrinsic capability (IC), application parameters (AP) and the human factors (HF), are, in the first instance, investigated separately. . The intrinsic capability stands for the pure physical-technological process of the signal detection caused by the waves or the rays from a material defect in the presence of noise (caused by the material and the devices). This intrinsic capability is the upper bound of the possible reliability. Already when measuring this intrinsic capability for thick walled components the original one-parameter POD must be extended to a multi-parameter POD, where, in addition to the defect size, a number of additional physical parameters, such as the grain size distribution (or attenuation), defect depth, and angle or surface roughness, must be considered. For real life cycle assessments it is necessary to evaluate the signal response from real defects. The industrial application factors, e.g. coupling conditions, limited accessibility, heat and environmental vibrations, diminish the reliability. The amount of reduction can be determined quantitatively, if the underlying conditions are controlled. In case they are not controlled it is necessary to count for a fluctuation in the reliability in the field anyway. The third group of important influencing factors are the human factors, which do not only cover the individual performance capability of the inspectors but also the design of the working place,the procedure, the teamwork quality, interaction with systems, the organization, and finally, the relationship between the companies involved in the inspection process and to which extend the responsible parties are aware of it. When comparing an “ideal inspection” with a “real inspection” it is worth whileto look how the existing practices, rules and standards support reliable testing and where the “delta” is. In the context of vigor, with respect to the industrial end user, it needs to be shown how the level of reliability of NDE, influenced by the different factors, has an impact on acceptance or rejection of safety critical parts.
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| 14:50 |
Break |
| 15:20
(close)
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Session 1 - New Methods I |
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| Session chair: |
D. Forsyth, TRI, Austin, USA |
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J.H. Kurz, DB Systemtechnik, Brandenburg-Kirchmöser, Germany |
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3
15:20
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NDE Reliability Enhancement Using Model Assisted POD
L.J. Bond, T.A. Gray, J.N. Gray, W.Q. Meeker, Iowa State University, Ames, USA
P. Ramuhalli, Pacific Northwest National Laboratory, Washington, USA
Abstract:
Challenges being faced for in-service inspection (ISI) and monitoring to ensure the enduring safety...
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Abstract: minimize
Challenges being faced for in-service inspection (ISI) and monitoring to ensure the enduring safety of civil infrastructure, and at the same time reduce the costs of operation and maintenance. There are some concerns regarding effectiveness of current ISI for detection of early degradation, such as in relation to life extension. With a leak-before-break design philosophy degradation and cracking is highly unlikely to impact safety. However, if more proactive management of material degradation, is to be adopted new methodologies are needed. These challenges have been highlighted with nuclear power industry license extensions to permit operation from 40-60 years, and consideration of the feasibility of a second license extension from 60-80 years. There is a need to avoid surprises when ISI is performed at an outage and a response degradation of reduction in inspection intervals can be expensive. Attention is also being focused on small modular reactors (SMR) that are being considered for deployment with reduced ISI requirements and enhanced on-line monitoring. The situation is further complicated by the improvements in inspection technology that is detecting “indications” that have most probably been in structures since manufacture but are only now being seen. With new technology there is a merging between NDE and that which has been considered structural health monitoring (SHM). Advanced diagnostics, and prognostics, is being used for active components to enable condition based maintenance (CBM), and programs are reducing failures. Attention is now moving to seeking to quantify POD for monitoring early degradation of passive components, for example concrete, cables, pipes, and reactor pressure vessels. This paper will consider model assisted POD in the context of the requirements for NDE and on-line monitoring, diagnostics and prognostics, looking towards legacy nuclear power plants, next generation SMR, and potentially other structures which merge applications of on-line monitoring for both SHM and prognostics. There is a need to move performance metrics beyond methods for macro-defects, such as crack detection and sizing, to address early degradation and prognostics.
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4
16:00
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Evaluation of Radiographic Testing Performance with an Advanced POD Approach
D. Kanzler, Applied Validation of NDT, Berlin, Germany
C. Müller, BAM, Berlin, Germany
J. Pitkänen, Posiva, Eurajoki, Finland
Abstract:
POD is the most often used approach for the evaluation of the reliability of non-destructive testin...
more
Abstract: minimize
POD is the most often used approach for the evaluation of the reliability of non-destructive testing methods in critical areas. But especially for those cases the requirements for a sufficient amount of data, adequate type of defects and the statistical requirements are high. The claim for checking these requirements is not new, but never the less often ignored. Especially the large amount of data for critical real defects seems too often to be not really solvable. In this presentation we show an approach to use real defect data with knowledge from former testing results with the same equipment, in a useful adequate way. Furthermore we introduce a method to evaluate the real defect description parameters for the radiographic testing. This approach was used for a joint project with the company POSIVA, which is building a final depository for spent nuclear fuel in Finland. Radiographic testing is one of the NDT-methods they use to test the electron beam weld of the copper canister. The copper canister will be used in the deposit as a corrosion barrier within the deposit concept. Through the high sophisticated manufacturing methods of the canister there are almost no material defects, which could be used for reliability evaluation. In this context the idea of Bayesian Updating of the POD with real defect data with former results from artificial defect data was born to get a useful evaluation.
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5
16:20
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Merging of Experimental and Simulated Data Sets with a Bayesian Technique in the Context of POD Curves Determination
B. Chapuis, CEA LIST, Gif-sur-Yvette, France
N. Dominguez, Airbus Group Innovations, Toulouse, France
P. Willaume, T. Yalamas, PHIMECA Engineering, Cournon d'Auvergne, France
F. Jenson, SAFRAN, Magny Les Hameaux Cedex, France
Abstract:
POD curves are usually described using a parametric model which relates the probability to detect a...
more
Abstract: minimize
POD curves are usually described using a parametric model which relates the probability to detect a specific defect to one of its geometrical characteristics, usually its size. The parameters of the model are estimated following a statistical procedure applied to a set of inspection results which are obtained thru dedicated experimental campaigns. Statistical significance requires that 60 to 80 mock-ups containing realistic flaws are fabricated and inspected by several inspectors. This costly and time consuming process must be done for each NDT procedure for which a measure of NDT reliability is required. Consequently, cost and time reduction of POD trials is currently a major issue. One way to achieve cost reduction is to replace some of the required experimental data with numerical simulation results. This idea follows the concept of Model Assisted POD (MAPOD). POD curves are no longer estimated from a fully empirical dataset but rather from a mix of experimental and simulated data. Simulations are performed using physics-based models, whose predictions are validated for the considered application case. In order to make the approach suitable for industrial needs, it is required that uncertainties introduced in the process thru the merging of simulation and experimental data are assessed. In this paper, a statistical method based on Bayesian updating is proposed, which mixes numerical simulations and information brought by the measurements. Traditionally, POD curves are assessed using Maximum Likelihood Estimation methods using either hit/miss or signal response data. This article only deals with hit/miss data. Following Berens article, the POD is modelled by a log-logistics function. Hit/miss data is treated as a Bernoulli’s variable and Bayesian updating is performed on the POD model to assess the posterior distributions of the POD parameters assuming non-informative prior distributions on them. Finally, Monte Carlo simulations are run to assess the confidence band POD. A practical implementation of the approach to a high frequency eddy current inspection for fatigue cracks is presented.
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| 16:40 |
Break |
| 17:10
(close)
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Session 2 - New Methods II |
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| Session chair: |
D. Forsyth, TRI, Austin, USA |
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J.H. Kurz, DB Systemtechnik, Brandenburg-Kirchmöser, Germany |
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6
17:10
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Simulation-Supported POD for Ultrasonic Testing – Recommendations from the PICASSO Project
F. Schubert, Fraunhofer IKTS, Dresden, Germany
N. Dominguez, Airbus Group Innovations, Toulouse, France
V. Dorval, C. Gilles-Pascaud, R. Raillon-Picot, CEA, Gif-sur-Yvette, France
H.-U. Baron, J. Farnhammer, MTU Aero Engines, München, Germany
T. Barden, Rolls-Royce, Bristol, UK
J.-Y. Chatellier, Snecma, Moissy Cramayel, France
Abstract:
The objective of the European project PICASSO (Improved reliability inspection of aeronautic struct...
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Abstract: minimize
The objective of the European project PICASSO (Improved reliability inspection of aeronautic structures by simulation-supported POD) was to build a new and original concept of simulation-supported Probability of Detection (POD) curves based on Non Destructive Testing simulations. This new methodology is based on the replacement of some of the experimental data with simulation results to obtain accurate and reliable POD curves with significantly less personnel and material costs. The present paper presents the main results of the PICASSO project for ultrasonic testing and addresses the most crucial aspects of the new approach, e.g. the definition of the noise level, the validation of the modeling tools, the combination of experimental and numerical data, and the specification of the uncertainty parameters and their statistical distribution. From the results recommendations for the practical use of simulation-supported POD curves are given.
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7
17:30
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Quantifying NDE Reliability from ENIQ Qualification Information
I. Virkkunen, M. Kemppainen, K. Miettinen, Trueflaw, Espoo, Finland
Abstract:
The current trend towards risk-informed inspection planning, increasing requirements on plant safet...
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Abstract: minimize
The current trend towards risk-informed inspection planning, increasing requirements on plant safety and aging of power plants increase the importance of quantifying NDE reliability in the Nuclear industry. At the same time, there's large body of work already done to ensure NDE reliability in the form of inspection qualification. In Europe, this mostly takes the form of ENIQ-style qualification. However, attempts to infer quantitative NDE reliability information from existing qualification data have met with limited success. In particular, numerous approaches have been tried to estimate POD curves based on qualification data. These include the MIL-HDBK-1823A statistical approach, Bayesian approach and others. Unfortunately, this work has, to date, been largely unsuccessful due to lack of data or test pieces for statistical analysis, or in some cases due to improper distribution of available data.
The present paper introduces an alternate approach for estimating NDE reliability from existing qualifications. In stead of focusing on the actual inspection results gathered from the qualification trials (which are few in number), the approach focuses on the qualification requirements, i.e. test piece trials and related pass-fail criteria. A set of relevant performance criteria (i.e. POD curve or sizing error) is then tested against the qualification requirements to determine the pass probability for an inspector having such a performance. The pass probabilities can be calculated (e.g.) using Monte-carlo method. The highest performance that will likely fail qualification can be used as a lower limit estimate of performance for inspectors who will pass the qualification.
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8
17:50
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Simulation Assisted POD in the Aeronautical Context
F. Reverdy, M2M-NDT, Les Ulis, France
N. Dominguez, Airbus Group Innovations, Toulouse, France
S. Mahaut, CEA, Gif-sur-Yvette, France
F. Jenson, SAFRAN, Magny Les Hameaux Cedex, France
Abstract:
Performances and reliability of NDT operations are often quantified through the determination of Pr...
more
Abstract: minimize
Performances and reliability of NDT operations are often quantified through the determination of Probability of Detection (POD), which can then be used in lifecycle management approaches like the damage tolerance design. Cost issues often limit the possibility to access POD curves. Recent progress in NDT models and POD methodology by means of uncertainty propagation through simulation codes open the door to powerful simulation-based POD curves. This helps to drastically decrease the cost of a POD study. In the present paper we present applications of POD curves obtained using simulation for the aircraft industry. The use of such results in justification documents requires careful validation and robustness demonstration. This paper proposes solutions to address these issues and progress towards a use in the industry.
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9
18:10
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Estimating Probability of Detection Curves Related to Eddy Current Sender – Receiver Probes
A. Rosell, GKN Aerospace, Trollhättan, Sweden
G. Persson, H. Wirdelius, Chalmers Univ. of Technology, Göteborg, Sweden
Abstract:
Sender – receiver probes are commonly used in eddy current procedures for crack detection. Such pro...
more
Abstract: minimize
Sender – receiver probes are commonly used in eddy current procedures for crack detection. Such probes give in general a non-linear signal response as a function of the crack size. Berens approach is the classical method used for analysis in probability of detection (POD) assessments. This statistical parametric method requires 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 around the linear regression line. If the eddy current procedure is showing a non-linear response characteristic then the method for estimating the POD curve must have a different approach. 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. Such an estimation requires a large number of calculations where input parameters are selected from their estimated distributions of variation. The finite element method is used for the eddy current signal response predictions within this work. In order to manage a large number of calculations at several crack sizes we suggest the use of a meta-model approach. The meta-model is then used for POD estimation according to proportion of signal response above the detection level at different crack sizes, a method which do 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 but must include essential parameters, including their variations, relevant in the specific crack size range. This work describes the sender-receiver probe model and concludes, by the use of design of experiments, the essential parameters and how they relate to the inspection set up. The suggested meta-model approach is then evaluated with respect to the result of the model based POD curve estimation. The result of the non-parametric POD curve estimated by the use of the meta-model is compared to the classical approach of analysis.
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| 18:30 |
Poster Evening |
October 8, 2013
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| 09:00
(close)
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Session 3 - New Methods III |
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| Session chair: |
L.J. Bond, Iowa State University, Ames, USA |
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M. Carboni, Politecnico di Milano, Italy |
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10
09:00
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A Review of POD Estimation from Multiple Sources of Data
D. Forsyth, TRI, Austin, USA
Abstract:
In the process of estimation of probability of detection (POD), the collection of relevant data can...
more
Abstract: minimize
In the process of estimation of probability of detection (POD), the collection of relevant data can be expensive and difficult. This has led to efforts to combine data from multiple sources, including from multiple experiments, from experiments on simple canonical geometries, from data collected in actual field inspection performance, and from data generated by simulation. Different mathematical approaches have been tried, including Bayesian updating of POD parameters, "transfer functions" to estimate differences between experimental data and POD target inspections, and direct modification of modeled data by experiment and the reverse of modifying experimental data by modeled data followed by a POD fit.
In this presentation, we will review some of these previous efforts and recent progress. These include a NATO Research and Technology Organisation Committee on the use of field data, and the efforts of many researchers involved in the Model Assisted POD (MAPOD) Working Group.
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11
09:40
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The Potential in Simulations and Meta-Modeling for Understanding and Development of NDE
P. Hammersberg, G. Persson, H. Wirdelius, Chalmers Univ. of Technology, Göteborg, Sweden
Abstract:
By combining detailed mathematical modeling of the physics in ultrasonic non-destructive testing wi...
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Abstract: minimize
By combining detailed mathematical modeling of the physics in ultrasonic non-destructive testing with a broader empirical model-building using the response surface methodology, several interesting problem characteristics has been observed; (1) It is possible to generate realistic synthetic probability-of-detection curves (POD) for specific testing procedures with a remarkable resemblance with experimentally determined POD-curves, without detailed physical modeling of parameters at the systems level; (2) The meta-model of the complex system resolve difficult contrasts from the experimental set-up; (3) The meta-model play an important role for early parameter studies building knowledge of the development of robust testing procedures. The combined methodology rests on a verified and accurate simulation of the ultrasonic data collection, an overlaying procedure for screening system parameters for building of system describing meta-models and the use of Monte-Carlo simulations of the detectability response. The successful results in (1) appears to be more related to the choice of the right statistical distribution of the input variables rather than detailed physical modeling of each parameter combination, pointing at the hypothesis that small models errors cancel-out and/or are drenched by the overall variability of system parameters. This procedure opens for sub-sequent parameter studies of at an elevated system performance level.
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12
10:00
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Simulation Based POD Estimation for Radiographic Testing of Turbine Blades
H.-U. Baron, MTU Aero Engines, München, Germany
C. Bellon, A. Deresch, BAM, Berlin, Germany
B. Henkel, MTU Aero Engines, München, Germany
Abstract:
During manufacturing of turbine blades in some cases pores can appear. A pore is a possible startin...
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Abstract: minimize
During manufacturing of turbine blades in some cases pores can appear. A pore is a possible starting point of a crack, which can cause breakage of the blade.
Here radiographic inspection is employed for finding such pores within the turbine blade roots.
As a measure for the reliability of the inspection the probability of detection (POD) is evaluated. It is possible to estimate the POD using radiographic simulation software.
The simulation software aRTist is applied to a real example from the aero engine manufacturing industry.
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| 10:20 |
Break |
| 10:50
(close)
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Session 4 - New Methods IV |
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| Session chair: |
L.J. Bond, Iowa State University, Ames, USA |
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M. Carboni, Politecnico di Milano, Italy |
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13
10:50
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The Reliability of Model-Based NDT in Civil Engineering Using Vibration-Based Inspection Method Including Models Coupling Quality
M. Deeb, V. Zabel, Bauhaus-Universität Weimar, Germany
Abstract:
The estimation of the probability of detection (POD) of a certain damage in a structure by means of...
more
Abstract: minimize
The estimation of the probability of detection (POD) of a certain damage in a structure by means of non-destructive testing is usually based on the statistical evaluation of experiments with a large number of test specimens. In civil engineering this approach is usually rather impractical due to the uniqueness and size of the considered systems. Therefore it is suggested to replace the large number of physical tests by numerical simulations what leads to the so-called model-assisted probability (MAPOD) of detection approach.
To identify global damage in civil engineering structures, the application of vibration-based methods has become popular in recent years. Several damage detection methods that are based on vibration measurements were developed in previous years. In this contribution the POD of damage in a civil engineering structure by means of vibration measurements is considered.
Vibration tests using different levels of damage severity as well as a variety of test setups, excitations and response measurements are simulated numerically. An important issue in this context is an appropriate modelling of the damage to be detected, such that the simulated signals are representative for signals that would be measured on a physical structure. The damage indicator applied here is related to the energy of the signal that is derived from structure response. The quality of the results is influenced by several aspects including the coupling of the different stages of analysis.
From the results the influence of the considered parts of the methodology is estimated such that an assessment of both the parts of the analyses and the global result is possible in terms of the POD.The contribution demonstrates the capability of combining numerical simulations and the methodologies to determine a POD for a certain damage that were developed for non-destructive testing. This implies also uncertainties and challenges. However, in situations where a large test series cannot be performed, such as for most civil engineering structures, the proposed methodology is a sensible approach.
Future work will be related to different kinds and locations of structural damage and alternative approaches for the evaluation of the probability of damage detection (POD).
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14
11:10
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Validation of the Rotating UT Probe for In-Service Inspections of Freight Solid Axles by Means of the MAPOD Approach
M. Carboni, Politecnico di Milano, Italy
C. Gilardoni, Gilardoni, Mandello del Lario, Italy
S. Cantini, Lucchini RS, Lovere, Italy
Abstract:
The present scenario of freight applications in Europe is characterized by a trend towards rolling ...
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Abstract: minimize
The present scenario of freight applications in Europe is characterized by a trend towards rolling stock renewal and a new approach to periodical inspection and maintenance; this is a consequence of some evidences coming from service and showing potential inconsistency in general safety levels. A specific NDT technique, based on more than 40 years of service experience on passenger wheel-sets inspection, is here proposed for periodical NDT on freight wheel-sets. The ultrasonic testing technique is based on a rotating probe-holder to be applied at the ends of the mounted axle and able to inspect its critical sections with different angled probes. To inspect such critical sections such as press fits and geometrical transitions, the testing device is characterized by a set of ultrasonic transducers emitting longitudinal waves at a typical nominal frequency of 4 MHz and at different angles into the axle. The structural integrity of the wheel-set is then based, together with other factors, on the determination of the Probability of Detection (POD) curve of the rotating probe. An experimental campaign to derive the POD curve can be costly and time consuming, especially considering the determination of its confidence range. For this reason, in the present research, a Model-Assisted POD (MAPOD) approach was considered. Initially, different sets of artificial defects, obtained by EDM, were introduced on the external surface of three solid axles made of A1N steel grade. All the defects were then inspected by a rotating probe, with the aim to derive their response, considering 4 MHz and 2.25 MHz transducers. The effect of the different time of flight characterizing the defects located at the different sections of the axles was, instead, determined by suitable numerical simulations carried out using the CIVAnde dedicated software package. Combining experimental and numerical results allowed to derive the MAPOD curve for the considered rotating probe with less effort with respect to the traditional experimental approach and to optimize the set-up of the rotating probe itself. As a result, the MAPOD curves of the rotating probe device are compared to the POD of standard UT inspection from axle end and a simulation of the reliability of inspection intervals is presented.
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15
11:30
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Methods to Assess the Quality of Non-Destructive Testing in Civil Engineering Using POD and GUM for Static Calculations of Existing Structures
S. Feistkorn, BASE, Berlin, Germany
A. Taffe, HTW, Berlin, Germany
Abstract:
To draw reliable conclusions from results gained with non-destructive testing methods in civil-engi...
more
Abstract: minimize
To draw reliable conclusions from results gained with non-destructive testing methods in civil-engineering (NDT-CE) it is important to know about the quality of results. Since recent times, the POD (probability of detection) according to MIL-HDBK-1823A and Berens Report is established in non-destructive testing in civil engineering (NDT-CE) to assess the reliability of qualitative testing problems. For determining the uncertainty of measurements of quantitative (metric) problems the Guide (Guide to the Expression of Uncertainty in Measurements - GUM) is used in NDT-CE.
Now, a new approach is to adapt both methods to get statistic secured measurement results with NDT-CE from existing structures like pre-stressed bridges.
This paper introduces, in which fields of static calculations based on stochastic models NDT-CE results analyzed with POD and the Guide can be used.
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16
11:50
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Reliability Considerations of NDT by Probability of Detection (POD) Determination Using Ultrasound Phased Array – Results from a Project in Frame of the German Nuclear Safety Research Program
J.H. Kurz, DB Systemtechnik, Brandenburg-Kirchmöser, Germany
S. Dugan, ENSI, Brugg, Switzerland
A. Jüngert, MPA Universität Stuttgart, Germany
Abstract:
Reliable assessment procedures are an important aspect of maintenance concepts. Non-destructive tes...
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Abstract: minimize
Reliable assessment procedures are an important aspect of maintenance concepts. Non-destructive testing (NDT) methods are an essential part of a variety of maintenance plans. Fracture mechanical assessments require knowledge of flaw dimensions, loads and material parameters. NDT methods are able to acquire information on all of these areas. However, it has to be considered that the level of detail information depends on the case investigated and therefore on the applicable methods. Reliability aspects of NDT methods are of importance if quantitative information is required. Different design concepts e.g. the damage tolerance approach in aerospace already include reliability criteria of NDT methods applied in maintenance plans. NDT is also an essential part during construction and maintenance of nuclear power plants. In Germany, type and extent of inspection are specified in Safety Standards of the Nuclear Safety Standards Commission (KTA). Only certified inspections are allowed in the nuclear industry. The qualification of NDT is carried out in form of performance demonstrations of the inspection teams and the equipment, witnessed by an authorized inspector. The results of these tests are mainly statements regarding the detection capabilities of certain artificial flaws. In other countries, e.g. the U.S., additional blind tests on test blocks with hidden and unknown flaws may be required, in which a certain percentage of these flaws has to be detected. The knowledge of the probability of detection (POD) curves of specific flaws in specific testing conditions is often not present. This contribution will present the results of a research project designed for POD determination of ultrasound phased array inspections of real cracks. The continuative objective of this project is to generate quantitative POD results. Different POD applications will be shown. The distribution of the crack sizes of the specimens and the inspection planning will be discussed, and results of the ultrasound inspections will be presented. Furthermore, additional considerations for POD determination of phased array inspections of real cracks will be discussed. In the context of the results, the remaining uncertainty of the inspections has to be taken into consideration for failure analysis.
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| 12:10 |
Lunch |
| 13:00
(close)
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Session 5 - Human Factors |
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| Session chair: |
C. Müller, BAM, Berlin, Germany |
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J. Pitkänen, Posiva, Eurajoki, Finland |
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17
13:00
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Safety and Reliability – Resilience Engineering Prevents Systems from Failing
B. Fahlbruch, TÜV NORD EnSys Hannover, Berlin, Germany
Abstract:
Incidents, near-misses and quality problems are signs of the system’s drift to danger. How do these...
more
Abstract: minimize
Incidents, near-misses and quality problems are signs of the system’s drift to danger. How do these negative outcomes develop, which processes support the drift to danger? An integrated view on safety and reliability will be presented with a focus on human, organizational and inter-organizational factors. The process of NDT can be affected not only by the inspector, organizational and inter-organizational factors may promote the system’s drift to danger as recent examples will show. Time or production pressure, inappropriate procedures or leadership as well as conflicting goals can lead inspectors to perform their inspection task not in the planned way. Resilience engineering helps to manage and prevent unexpected and unwarranted outcomes.
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18
13:40
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Improving Inspection Reliability Through Operator Selection & Training
B. McGrath, L. Carter, AMEC, Warrington, UK
Abstract:
A number of years ago the UK’s Health & Safety Executive sponsored a series of three projects inves...
more
Abstract: minimize
A number of years ago the UK’s Health & Safety Executive sponsored a series of three projects investigating the application of manual ultrasonics, which endeavoured to establish the necessary steps that ensure a reliable inspection is performed. The results of the three projects were each reported separately on completion and also presented at number of international conferences.
This paper summarises the results of these projects from the point of view of operator performance. The correlation of operator ultrasonic performance with results of aptitude tests is presented along with observations on the impact of training and qualifications of the operators. The results lead to conclusions on how the selection and training of operators could be modified to improve reliability of inspections.
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19
14:00
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We Know How To Improve Inspection Reliability - Why Don’t We Do It?
L. Carter, B. McGrath, AMEC, Warrington, UK
Abstract:
The PANI projects, sponsored by the UK’s Health & Safety Executive, were completed and reported in ...
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Abstract: minimize
The PANI projects, sponsored by the UK’s Health & Safety Executive, were completed and reported in 2007. However, when NDT vendor companies were subsequently surveyed in 2010 it was found that only a small number had taken steps to change the way they operated in the light of the findings from these projects. In addition, few respondents could see how the results from the PANI projects were relevant to other NDT Techniques.
This paper summarises the results of the PANI projects with respect to the impact of the organisation on the reliability of inspections covering the inspection process and the role of the client. The results of the survey are presented which highlights the best media for communicating results. The relevance of the human factors lessons from these manual ultrasonic investigations to the application of other NDE techniques is emphasised.
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20
14:20
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Holistic Risk Assessment and Risk Prevention Approach to the Mechanized NDT and the Inspection Procedure
M. Bertovic, Berlin, Germany
C. Müller, BAM, Berlin, Germany
J. Pitkänen, Posiva, Eurajoki, Finland
U. Ronneteg, SKB, Oskarshamn, Sweden
B. Fahlbruch, TÜV NORD EnSys Hannover, Berlin, Germany
Abstract:
The difficulty to deal with human factors in non-destructive testing (NDT) stems from their diversi...
more
Abstract: minimize
The difficulty to deal with human factors in non-destructive testing (NDT) stems from their diversity and complexity – no single human or organizational factor is responsible for the entire fluctuations in the NDT performance. The typical approach to decrease the variability in the inspection results had been found in replacing manual NDT with mechanized methods. However, even though some human errors can be avoided by automating the process, there are new risks that can arise from its application and need to be further investigated. To address this problem, a combination of theoretical and practical approaches should be applied, where the source of error is not seen only in the operator, but also in his interaction with social and technical systems, as well as the organization.
An analysis of potential risks in the use of mechanized inspections methods for spent fuel canisters has shown potential for human error in acquisition, as well as in the evaluation of the gathered results. Assessed causes of those errors lay in the operator, but also in the organization and in shortcomings of the inspection procedure. The aim of the analysis was to provide with preventive measures and optimization recommendations. Those include further automation of the process, application of human redundancy, improvements of the inspection procedure, hardware and software improvements etc. Before improvements can be made, there is a need to understand the resulting processes and the influence of their interaction on the inspection results. The results have shown that when working with an automated system, one must avoid over relying on its proper functioning and form appropriate trust towards automation. Furthermore, human redundancy should be applied only in cases where the redundant operators are completely unaware of each other, in order to avoid the effects of social loafing and shirking.
Inspection procedure is one of the most important tools in the application of NDT. On an example of ultrasonic data evaluation, the results will show an improvement of an NDT instruction as a result of consideration of the effectiveness, efficiency and user satisfaction.
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|
| 15:00 |
Break |
| 15:30
(close)
|
Session 6 - Applications in Industry I |
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| Session chair: |
U. Ronneteg, SKB, Oskarshamn, Sweden |
|
G. Selby, EPRI, Charlotte, USA |
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21
15:30
|
How Are We Still Flying? Contributions of NDE Reliability Within Overall Risk Management for Airframes.
L. Schaefer, Blue Origin, Kent, USA
Abstract:
In-service health monitoring of riveted Aluminum Fuselage & Wing structures has been a vital compon...
more
Abstract: minimize
In-service health monitoring of riveted Aluminum Fuselage & Wing structures has been a vital component of continued air-worthiness validation for both civilian and military aircraft around the world. The characteristics & variation of acute and chronic modes of degradation, as well as the NDE sensing strategies applied to detect them, are complex and have undergone considerable development over the past 3 decades. Often times, as we have seen in recent early Boeing fuselage failures beyond the visual damage tolerance assumptions, we are challenged to understand, in a modular way, the reliability of applied NDE. This paper conducts a literature review of the technologies, modeling, and reliability assessments deployed for the inspection of riveted Aluminum aircraft structure. From this review we will attempt to understand how well this segment of NDT is working, and what trends are occurring.
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22
16:10
|
Novel Approach for Improving Reliability of Phased Array Ultrasonic Testing and Monitoring of Pressure Swing Adsorber Vessels Integrity against Fatigue Cracking
M.G. Lozev, BP Products North America, Naperville, USA
M. den Ouden, Applus RTD, Rotterdam, Netherlands
K.-H. Dust, BP Europe, Lingen, Germany
R. Brodzinski, BP Products North America, Naperville, USA
R. Spencer, E. Todorov, EWI, Columbus, USA
L. Le Ber, M2M-NDT, Les Ulis, France
M. Czubanowski, TÜV NORD EnSys, Hamburg, Germany
Abstract:
Stringent requirements for non-destructive, pre-start-up testing and on-line assurance against fati...
more
Abstract: minimize
Stringent requirements for non-destructive, pre-start-up testing and on-line assurance against fatigue cracks in Pressure Swing Adsorber (PSA) vessels at BP site in Germany were enforced by the TÜV-Nord, an authorized representative of the German Technical Inspection Authority. This paper summarizes the results of developing and deploying an advanced ultrasonic phased array technology for reliable detection and monitoring of fatigue cracking, and reducing the risk of missing fatigue cracks, avoiding potential hydrogen leaks and catastrophic failure of the vessels.
TÜV-Nord as a third party was involved in all stages of development. Fitness for Service assessment to define crack critical sizes was performed. High frequency ultrasonic linear phased array probes, electronics and advanced imaging as the most promising technology were selected. An inspection procedure that did not require scaffolding, opening the vessel and removing the paint coating was developed and optimized via modelling and simulations. A novel validation method using Modelled Assisted Probability of Detection (MAPOD) approach was applied. Portable mock-ups with statistically valid population of real and realistic cracks were used to perform high rigor POD study. Vendor’s equipment, procedure and operator were qualified during open and blind trials. An approval from TÜV-Nord on technology, techniques and vendor was obtained. A fully automated ultrasonic phased array testing of 10 PSAs at BP site in Germany was completed and inspection results were accepted by TÜV-Nord.
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23
16:30
|
Numerical Evaluation of ROC of Potential Mapping
S. Keßler, cbm, TU München, Germany
C. Gehlen, TU München, Germany
Abstract:
The corrosion of the reinforcement is often the major cause for the end of service life of reinforc...
more
Abstract: minimize
The corrosion of the reinforcement is often the major cause for the end of service life of reinforced concrete structures. Cracks due to corrosion are the first visible sign of the deterioration process. But in this stage the deterioration process is advanced. Now, it is too late for a cost-effective and pro-active maintenance strategy. Once the corrosion process is initiated, corroding areas can be detected non-destructively through potential mapping. So, the inspection results coming from potential mapping are of vital importance to ensure the safety and reliability of our infrastructure.
The crucial factor for successful corrosion detection is a good probability of detection of potential mapping. But the knowledge about the accuracy of the measurement method itself is not sufficiently well known. The problem is the knowledge about the true corrosion condition state, which is only identifiable by replacement of concrete cover. No owners will agree to open a whole structure for evaluating the accuracy of an inspection method. In order to solve that problem an approach based on numerical models is pursued in this research.
The aim of the paper is the numerical analysis of the accuracy of the inspection method potential mapping. What are the advantages and disadvantages of the numerical analysis of probability of detection and receiver operating characteristics? What are the consequences for the measurement procedure in practice? Is it possible to derive recommendation for a suitable evaluation method of potential mapping?
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| 19:30 |
Workshop Dinner |
October 9, 2013
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| 09:00
(close)
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Session 7 - Applications in Industry II |
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| Session chair: |
M.G. Lozev, BP Products North America, Naperville, USA |
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U. Ronneteg, SKB, Oskarshamn, Sweden |
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24
09:00
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Inputs for the Performance of an Industry Round Robin to Determine the Reliability of Remote Visual Examination
G. Selby, J. Lindberg, EPRI, Charlotte, USA
M.T. Anderson, P. Ramuhalli, Pacific Northwest National Laboratory, Washington, USA
Abstract:
Globally, regulators have challenged the reliability and capabilities of remote visual examinations...
more
Abstract: minimize
Globally, regulators have challenged the reliability and capabilities of remote visual examinations for reactor internals inspections. In the United States, the Electric Power Research Institute (EPRI) is cooperating with the U.S. Nuclear Regulatory Commission (NRC) – Office of Research, and their contractor, Pacific Northwest National Laboratory (PNNL) to determine the capabilities and reliability of remote visual examination. This project is currently in progress, and consists of a complex multi-year, three phase industry round robin program that began in 2010 with phase 2 testing being completed in February 2013.
The focus of this industry round robin program is to quantify the current capabilities of remote visual examination technology, including equipment, procedures, and personnel to determine the reliability of remote visual examination for detection of cracking in austenitic stainless steel reactor internals components. This paper will discuss the testing approach being used, and the key attributes being tested as part of this industry round robin.
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25
09:20
|
The Benefits of Structured Inspection Qualification Programs
G. Selby, T. Seuaciuc-Osorio, EPRI, Charlotte, USA
Abstract:
Periodic inspection of critical components in a nuclear power plant is an essential item toward ens...
more
Abstract: minimize
Periodic inspection of critical components in a nuclear power plant is an essential item toward ensuring the safe operation of the facility and in imparting trust in the public it serves; ensuring the reliability of these inspections, therefore, is an important activity for all regulatory bodies and the industry as a whole. In order to do so, qualification programs have been established across the industry which can vary in approach from country to country. This paper discusses the benefits of a structured inspection qualification program such as the one implemented in the United States of America, highlighting the positive improvements it brings to issues of reliability and showing how it provides supporting data to answer questions of probability of detection and sizing performance, which are important in statistical analysis of failure risks; how it ensures repeatability; and how, being structured, it can potentially allow for direct measurements of the reliability of the program itself¾finally leading to the conclusion that a structured inspection qualification program brings invaluable benefits to reliability, which is its essential objective.
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26
09:40
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Advantages of AREVA GmbH Qualified Visual Inspections in Accordance with ENIQ
E. Tsvetkov, Framatome, Erlangen, Germany
Abstract:
The visual inspection is one of the most important NDT methods in nuclear power plants. The accredi...
more
Abstract: minimize
The visual inspection is one of the most important NDT methods in nuclear power plants. The accredited Testing Laboratory of AREVA GmbH, IBOO-G has done different qualifications in accordance with the ENIQ methodology. The variety of qualifications carried out in many European countries has shown that the accredited Testing Laboratory is able to carry out qualifications due to the requirements of the domestic qualification bodies and of the nuclear power plant operators.
The main advantages of a qualification and of an inspection carried out by the accredited Testing Laboratory of AREVA, IBOO-G are:
1.Development of specific equipment for each qualification within the Testing Laboratory.
Based on the requirements and on an accessibility study specific equipment is developed for the different inspection objects. The development of the equipment includes the choice of a camera and the construction/adaptation of a manipulator. The development of equipment within the Testing Laboratory from the same personnel who carry out the qualification and the inspection excludes the potential loss of information in the communication that could appear in case various personnel are involved in the development of equipment, realization of the qualification and the implementation of the inspection.
2.Implementation of the inspection by the same personnel who carry out the qualification.
Personnel who will perform the inspection are involved in the qualification process. They carry out the practical trials, prepare the technical justification and the inspection procedure. This means, that the personnel are more familiar with the inspection technique when it comes to implementation of the inspection.
3.Preparation of a specific inspection procedure for each qualification.
The development of specific equipment results in the preparation of a new technical justification and a new inspection procedure. In this way is possible to take the experience from previous qualifications and inspections into account in order to optimize the current qualification.
Realizing the increasing of the importance of ENIQ, AREVA GmbH, IBOO-G is continuously carrying out practical trials and improving its visual inspection technique and is able to cope with any customer requirements.
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|
| 10:00 |
Break |
| 10:30
(close)
|
Session 8 - Reliability of SHM |
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| Session chair: |
L. Schaefer, Blue Origin, Kent, USA |
|
M. Wall, ESR Technology, Abingdon, UK |
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27
10:30
|
Time Dependent Probability of Detection for Ultrasonic Structural Health Monitoring
J. Fisher, SwRI, San Antonio, USA
Abstract:
Ultrasonic inspection and structural health monitoring (SHM) of metal components has been demonstra...
more
Abstract: minimize
Ultrasonic inspection and structural health monitoring (SHM) of metal components has been demonstrated to be effective for detection and monitoring of fatigue-induced damage, corrosion damage, etc. However, traditional probability of detection (POD) approaches as used for nondestructive evaluations (NDE) are not directly applicable to SHM given (1) the fixed positions of the ultrasonic probe(s) and (2) the time-dependent nature of both the observations and the structural conditions. The fixed positions of the probes means that there is a lack of variation in SHM sensor response due to human factors, as has been previously discussed. This paper attempts to expand on previous efforts to define a meaningful POD for SHM of a given structure, by developing a framework for time-dependent POD based on gradual changes in the structure. The possibility of applying this philosophy to a structure monitored using guided waves will be discussed.
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28
11:10
|
Characterizing the Performance of Lamb Wave Based SHM Systems – A Two-Step Approach Based on Simulation-Supported POD and Reliability Aspects
F. Schubert, B. Frankenstein, G. Lautenschläger, M. Röllig, L. Schubert, Fraunhofer IKTS, Dresden, Germany
Abstract:
The performance of conventional NDE systems with one or a few sensors can be adequately described b...
more
Abstract: minimize
The performance of conventional NDE systems with one or a few sensors can be adequately described by classical POD concepts. In the case of Lamb wave based structural health monitoring (SHM) the situation is more complex. In SHM a larger number of permanently installed sensors arranged in a network configuration are often used. For this problem the conventional POD concept needs to be adapted since POD becomes a function of position or more general, a function of the specific network configuration. Moreover, the long-term behavior of sensors and electronics plays an important role since their degradation directly affects the POD of the SHM system over time. In the present paper a two-step approach to characterize the performance of Lamb wave based SHM systems based on POD and reliability aspects is presented.
In a first step we introduce a new POD concept for Lamb wave based sensor networks where the effective network aperture is used as a virtual scanning device. Therefore the conventional POD methods already known from classical UT can be directly transferred to SHM. The only exception is the location-dependent POD determined by the specific network configuration. For this purpose a simulation platform is presented that allows the calculation of location-dependent POD values and additionally offers the possibility to optimize the network configuration if the statistical distribution of flaws is empirically known. In a second step we address the age-dependent performance of sensors and electronics by presenting results of an extensive experimental and simulation-supported reliability study on CFRP integrated sensor systems. Environmental tests have been done to investigate the reliability of ultrasonic transducers and electronic components in the longterm. The tested sensor package concept has been specifically designed with respect to functionality (high efficiency of Lamb wave coupling) and reliability of hardware components. We discuss how these aspects can be incorporated in the classical POD framework. As a final result for the description of SHM system reliability we propose a time-dependent or age-related POD, i.e. a POD time curve, rather than a single POD value.
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29
11:30
|
Influences on Reliability and Performance of AU Based SHM Systems, Requirements and Approach for Detection Performance Assessment
C. Stolz, A. Haberl, C. Meisner, Airbus Defence and Space, Manching, Germany
Abstract:
Recent trends show an increasing need for prognostics and lifetime estimations for damage critical ...
more
Abstract: minimize
Recent trends show an increasing need for prognostics and lifetime estimations for damage critical structures in various industries. Military aviation is a major application area for Structural Health Monitoring (SHM) systems. Out of numerous SHM approaches being under investigation, sensor-based Acousto Ultrasonics (AU) systems which use guided waves for damage detection have great potential of meeting the future needs of autonomous life prognostics. Besides the technical development and integration of such systems, ways for the aeronautical certification are explored.
The reliability of SHM systems is a key issue for certification. Common understanding for assessing the performance and reliability in terms of damage detection is needed. Therefore the Probability of Detection (POD) is a major indicator. Existing approaches used in the field of NDT based on testing are not fully applicable to POD assessments due to restricted test efforts. Simulation based assessments will help to minimise the test effort to an acceptable scope. Simulation techniques need basic knowledge of wave propagation physics, material properties of monitored structures and influencing parameters. Detailed validation of the simulation techniques tools are necessary to satisfy the certification issues.
This paper presents reliability aspects in the context of sensor-based AU systems. Several influencing parameters on system reliability will be investigated. Effects of sensor integration, environmental conditions and guided wave modes on detection reliability will be considered.
The characterisation of performance and ways of an POD assessment of sensor-based AU systems will be discussed. Requirements for simulation tools are considered.
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30
11:50
|
Manual UT vs Permanently Installed Sensors
F. Cegla, Imperial College London, UK
Abstract:
The quantification of a complex system’s reliability is extremely difficult. The reliability of NDE...
more
Abstract: minimize
The quantification of a complex system’s reliability is extremely difficult. The reliability of NDE techniques is strongly influenced by the physics of the measurement technique, the procedure with which the NDE technique is applied and human factors that can lead to differences between actual and desired outcomes. The NDE group at Imperial College London has developed permanently installed ultrasonic thickness monitoring tools which allow frequent acquisition as well as automatic evaluation of ultrasonic wall thickness estimates. Several thousand sensors have been deployed in field and some of the outcomes from site data will be presented. The factors that influence the system’s performance will be discussed in this paper with a view to giving an indication of the different aspects that are important when trying to evaluate the reliability of a monitoring system compared to discrete manually collected conventional inspections.
|
|
| 12:10 |
Lunch |
| 13:00
(close)
|
Session 9 - Integrated Solutions I |
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| Session chair: |
J. Fisher, SwRI, San Antonio, USA |
|
F. Schubert, Fraunhofer IKTS, Dresden, Germany |
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31
13:00
|
NDE Reliability: Current Challenges and Actions in the USA
G. Selby, EPRI, Charlotte, USA
Abstract:
Often we perform NDE in order to comply with regulatory or other requirements, without taking credi...
more
Abstract: minimize
Often we perform NDE in order to comply with regulatory or other requirements, without taking credit for the reduction in flaw population that it provides. This reduction in flaw population can form part of the technical basis for the integrity of a system and potentially for a reduced inspection schedule in the future. One way to perform this analysis is by using probabilistic fracture mechanics. A current example in the US is the Extremely Low Probability of Rupture (xLPR) project, whose purpose is to verify the integrity of PWR piping systems that include nickel-alloy welds. The xLPR analysis will calculate the rupture probability by Monte Carlo simulations using probability distributions for flaw introduction, flaw growth, flaw coalescence, inspection reliability, leak detection reliability, and application of mitigations. The inspection reliability inputs include both probability of detection (POD) and probability of correct sizing. The POD has been calculated using a logistic statistical analysis of thousands of data points acquired during NDE qualifications. Questions remain as to whether, and how, to adjust this POD curve to account for the differences between the qualification environment and the environment in the power plant. Recent operational experience has highlighted the need for such an accounting.
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32
13:40
|
NDT Reliability in the Organizational Context of Service Inspection Companies
R. Holstein, DGZfP Ausbildung und Training, Berlin, Germany
D. Kanzler, Applied Validation of NDT, Berlin, Germany
C. Müller, BAM, Berlin, Germany
M. Bertovic, Berlin, Germany
Abstract:
Much of NDT-Reliability-Research in the past was done in the field of two high risk industries: (at...
more
Abstract: minimize
Much of NDT-Reliability-Research in the past was done in the field of two high risk industries: (atomic) power plants and aircrafts. The responsible organizations have been well aware of the risks and founded projects to understand and optimize critical steps during production, operation and maintenance. But the use of NDT is not limited to these two fields. The risks during operation of chemical plants, trains or windmills are different from the area above but evident. The coverage by legal regulations is relatively low. Instead of this owner responsibility, product liability and financial issues are the driving forces to do inspections and to use non-destructive testing. The different targets and financial issues are influencing the practice of NDT-inspections. A survey of this practice and its results are shown.
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33
14:00
|
Evaluating POD in Real Situations and the ‘Delta’ Factor
M. Wall, ESR Technology, Abingdon, UK
Abstract:
The use of Probability of Detection (POD) to characterise the reliability of non-destructive testin...
more
Abstract: minimize
The use of Probability of Detection (POD) to characterise the reliability of non-destructive testing is well established in safety critical and other industries including aerospace, nuclear and offshore. There are established methodologies for determining reliability from POD trials and increasingly by modelling. POD provides an important input to integrity and safety assessments.
For a variety of reasons POD in real situations may differ to that established in trials; for example due to human or environmental factors(HF) or application related (AP) factors such as defect tightness or characteristics, coatings, thresholds and sensitivities used, or component geometry or thickness. This difference between the POD in trials or modelling and real situations is referred to as the “delta-factor”. What would be the effect on POD if a crack was a facetted stress corrosion crack rather than fatigue, or if the crack was under compression? What would be the effect of combining NDT techniques or repeat inspection?
This paper shows a number of approaches used by NNDTC to evaluate the “delta” of reliability measurements to the field performance of NDT including: use of human reliability data, such as that arising from PISCIII; empirical measurements; the use of NDE simulators; derivation of the delta-factor using POD models; and use of POD trial data in real situations.
POD models developed by NNDTC are used to show how parametric differences can be assessed. An example is given of the use of “spot-the-ball” simulators intrinsic within these models and an NDE simulator developed for railway axle inspection can be used to evaluate operator effects. Methodologies for correcting for human factors using data from PISC III and comparison of automated and manual UT inspection are also described.
|
|
| 14:20 |
Break |
| 14:50
(close)
|
Session 10 - Integrated Solutions II |
|
| Session chair: |
J. Fisher, SwRI, San Antonio, USA |
|
F. Schubert, Fraunhofer IKTS, Dresden, Germany |
|
|
38
|
Test1
A. Schmidt, DGZfP, Berlin, Germany
Abstract:
TestKufa
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34
14:50
|
Practical Estimation of Probability of Detection in Modern Industrial Nondestructive Testing Systems
D. Forsyth, TRI, Austin, USA
Abstract:
The United States Air Force MIL-HDBK-1823 is a widely accepted document that describes practical an...
more
Abstract: minimize
The United States Air Force MIL-HDBK-1823 is a widely accepted document that describes practical and statistical tools for the estimation of probability of detection (POD) for nondestructive testing (NDT) systems. MIL-HDBK-1823 is well suited to analysis of most NDT systems that provide a scalar response (i.e. signal amplitude) in response to a discontinuity that can be characterized by a single scalar dimension. This discontinuity might be a fatigue crack in a known location, where the aspect ratio of the crack is understood and thus the crack can be represented in one dimension.
Modern NDT systems collect multi-dimensional data on components of engineered structures. The relevant discontinuities for the initial quality and long term operation of these engineered structures can be complex and multidimensional, such as distributed porosity or delaminations in composite materials. Rigorous measure of NDT system capability is still needed for quality control, risk assessment, and optimal engineering design.
In this presentation, we will discuss options for applying the principles of MIL-HDBK-1823 to these types of NDT systems. Multiple case studies will be presented.
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35
15:10
|
Reliability Studies, a Tool in the Development of Techniques for NDT of the Canister for the Swedish Spent Nuclear Fuel
U. Ronneteg, SKB, Oskarshamn, Sweden
M. Bertovic, Berlin, Germany
Abstract:
The Swedish KBS-3 design for the disposal of spent fuel is based on encapsulation of the fuel in ca...
more
Abstract: minimize
The Swedish KBS-3 design for the disposal of spent fuel is based on encapsulation of the fuel in canisters consisting of cast iron inserts and an outer 5 cm thick shield of copper. The canisters are embedded in bentonite clay and will be disposed in crystalline bedrock at a depth of about 500 m. To verify that the canisters fulfil the requirements, an extensive programme for quality control is developed. In this programme the use of non-destructive testing (NDT) is vital and therefore it is very important to develop reliable NDT methods.
Commonly, the reliability of NDT in the nuclear field is only analyzed on a technical basis, and only in the stage of the technical justification of the methods. Within the development of mechanical ultrasonic inspection techniques for the canister for the spent nuclear fuel, reliability analyses are used as an integrated tool already in the development phase. Sophisticated POD-calculations (Probability of Detection) are used to analyze the detection capabilities and thereby identify the weak spots and the needs for further improvement. Additionally, the reliability analyses also focus on the human factors during the application of mechanical inspection techniques, especially in the field of evaluation of collected data. Aided by the eye tracking methodology, the written instructions and their use during the data evaluation were experimentally investigated. The results will serve as a basis for optimization of the instructions and definition of needs for specific operator training.
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36
15:30
|
The Time Evolution of Actual Condition and Apparent Condition for an Inspected System
D. Horn, AECL, Chalk River, Canada
Abstract:
The actual condition of a system may not be identical to its apparent condition as reported from in...
more
Abstract: minimize
The actual condition of a system may not be identical to its apparent condition as reported from inspections. The apparent condition can be biased by non-detection of actual flaws, false calls of non-existent defects, incorrectly characterized indications, and lack of results from uninspected regions. Reliability analysis tools, such as probability of detection, false call estimation, and assessment of sizing uncertainty, are commonly used to compensate for the difference between the actual and apparent condition. However, these static corrections neglect the time evolution of the system condition, which may, over the system life cycle, diverge from the condition assumed by its operators.
In this work, we model the unobserved, underlying condition of a large system over decades of service life. Maintenance and repair activities, all contingent upon earlier inspection results, are included in the model. The apparent condition at each inspection date is then calculated by filtering the underlying condition through inspection reliability analysis. In this particular case study, a large historical data set permits us to compare predicted inspection results to those obtained over many years. The assumed distribution of degradation rates, effectiveness of repair, and inspection reliability parameters can then be adjusted to provide a more accurate picture of the actual system condition.
The history and predicted future life of a system are best obtained from this type of model, which permits evaluation of alternative scenarios for inspection priorities, assessment of repair effectiveness, and meaningful planning for end-of-life or life extension.
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37
15:50
|
Reliable Evaluation of the Acceptability of the Weld for Final Disposal Based on the Canister Copper Weld Inspection Using Different NDT Methods
J. Pitkänen, Posiva, Eurajoki, Finland
D. Kanzler, Applied Validation of NDT, Berlin, Germany
D. Brackrock, G. Brekow, C. Müller, BAM, Berlin, Germany
M. Bertovic, Berlin, Germany
U. Ewert, Teltow, Germany
Abstract:
The inspection of the sealing weld is an important phase for the evaluation of the acceptability of...
more
Abstract: minimize
The inspection of the sealing weld is an important phase for the evaluation of the acceptability of final disposal canister, but the weld is only a part of the 3D-shielding of copper shell. The main tasks for reliable NDT evaluation requires an extensive parameters evaluation - which contains typical inspection related items like repeatability, S/N-ratio, POD, setting up the equipment for inspection and all practices for inspections. The other parameters are material parameters, the variation of which must be taken into account in the evaluation of NDT-reliability. Further parameters include human factors and their interaction with technical systems; the effects of which were studied on an example of the evaluation of eddy current data. Final parameters are related to evaluation of detected defects, which means sizing and base for acceptance and this can be done in different ways. Some examples are given and results are compared with different methods for instance between radiographic testing and ultrasonic testing with raw data analysis and PA-SAFT results. Also preliminary curves for the evaluation of 55-defect metallographic results will be shown from EB-weld measurements. Some practical items concerning copper inspections will be also discussed related to acceptability.
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|
| 16:10 |
Break |
| 16:40 |
Poster Evaluation Session |
October 10, 2013
|
| 09:00 |
Introduction - Break-out-Sessions |
|
Overall moderation:
R. Holstein, DGZfP Ausbildung und Training, Berlin, Germany
B. McGrath, AMEC, Warrington, United Kingdom |
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| 09:30
(close)
|
Break-out Sessions |
|
Group 1
New Reliability Methods:
MultiparameterPOD, MAPOD, Bayesian
D. Forsyth, TRI, Austin, USA
P. Calmon, CEA LIST, Gif-sur-Yvette, France
|
Group 2
Reliability of SHM
J. Fisher, SwRI, San Antonio, USA
F. Schubert, Fraunhofer IZFP, Dresden, Germany |
Group 3
Human Factors
M. Bertovic, C. Müller, BAM, Berlin, Germany |
Group 4
Applications in Industry
U. Ronneteg, SKB, Oskarshamn, Sweden
W.D. Rummel, D & W Enterprises, Littleton, USA |
Group 5
Integrated Solutions and the “Delta”
G. Selby, EPRI, Charlotte, USA
L. Carter, AMEC, Warrington, United Kingdom |
|
|
| 12:00 |
Lunch |
| 13:00 |
Workshop Summary & Closure (end ca. 14:00) |