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P1
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POD Evaluation of Automated Ultrasonic Detection of Hard Alpha Inclusions in Titanium Alloys
D.S. Lozhkova, S.I. Trifonova, FSUE "VIAM", Moscow, Russia
Abstract:
The problem of POD of NDT is very important for Russian aerospace industry nowadays. Using FAAACС 3...
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Abstract: minimize
The problem of POD of NDT is very important for Russian aerospace industry nowadays. Using FAAACС 33.14 data is inexpedient because of significant difference between Russian and foreign titanium disks ultrasonic testing NDT manuals. Probability of defect detection versus its size curves are necessary for the deficiency evaluation of gas-turbine engine basic parts. Evaluation of gas-turbine engine basic parts deficiency is necessary for new procedure of resource calculation introduction.
Special research for reliability evaluation of automated titanium disks ultrasonic testing was made in FSUE “VIAM”. Special requirements for specimens with synthetic hard alpha inclusions were developed. Method of obtaining hard alpha inclusions with required nitride concentration was also developed. Using these requirements special titanium specimens with known size of hard alpha inclusions were manufactured. Further these specimens were inspected by different operators according to industrial manual of automated immersion UT inspection of titanium disks. Available places inspection was made with different wave types (longitudinal and shear) using transducer with different frequencies. As a result of automated UT inspection statistic information about defects which were found or missed was collected.
Mathematical means based on MIL-HDBK-1823A algorithm was developed for processing of collected statistic data. Preliminary curves of defect detection versus its size were obtained with this mathematical means.
These curves are preliminary because of shortage experimental data for plotting real curves. It is expedient use mathematical modeling data to add an experimental data. Mathematical model simulating automated UT inspection processes is to consider different defects forms and orientation. Our team is working on this problem now.
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P2
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MPT Inspection of Helicopters’ Driving Roller Chains Parts
V.S. Bondareva, T.D. Pavlova, A.V. Stepanov, FSUE "VIAM", Moscow, Russia
Abstract:
The work on control of parts of the drive roller chains for helicopters was carried out At the All-...
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Abstract: minimize
The work on control of parts of the drive roller chains for helicopters was carried out At the All-russian scientific research institute of aviation materials “VIAM”. The objective of this work was to detect radial cracks extending from a hole for the axle of the roller on the outer surfaces of the plates links, as well as transverse cracks on the surface of the rollers.
In this work optimum modes of the magnetization were designed and developed, indicator materials, which ensuring control on the conventional level of sensitivity “B”, was selected, and the demagnetization parts of roller chains was conducted.
The material of the inner and outer plates chain is steel “У7А”, surface - oxidation, the material of rollers is steel “20X”. Inspection of the parts was conducted by the residual magnetization method (RMM).
For inner and outer plates inspection it was selected a suspension, prepared on the basis of a concentrate of fluorescent magnetic powder “Diagma -1613” (the firm “Orion-M”). The plates were magnetized by the horizontal defectoscope for non-destructive testing (NDT) “UNIMAG 905 MDS”: circular magnetization, AC 1300A.
For the inspection surfaces of rollers it was selected a suspension, prepared on the basis of the black magnetic powder by specifications 6-14-1009-79 (the company “Anker”). Concentration of powder in the suspension was 20 g/l. The rollers were magnetized by the horizontal defectoscope for non-destructive testing (NDT) “UNIMAG 905 MDS”: circular magnetization, AC 1000A.
The proposed method will allow to carry out the control of parts of the drive roller chains for helicopters, to identify defects, as at the stages of production, and in the process of exploitation, to enhance the reliability and to increase the safety of aviation equipment.
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P3
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Types of Production and Operational Defects of the Multilayer Glued Constructions and Polymer Composite Materials Products and Methods to Detect Them
V.V. Murashov, FSUE "VIAM", Moscow, Russia
Abstract:
The defects caused by a low degree of curing of polymer matrix and deviations of material compositi...
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Abstract: minimize
The defects caused by a low degree of curing of polymer matrix and deviations of material composition from standard parameters in the whole volume of an article are attributed to the first hazard group (the highest degree of hazard). Defects caused by undercuring of the matrix lead to a decrease in heat-resistance, to a sharp reduction of such operational characteristics as water- and moisture resistance, to a decrease in resistance to attacks of aggressive environments . Deviations in chemical composition in a significant volume of components lead to essential changes in strength and elastic properties and worsen operational reliability.
Exfoliations are ascribed to the second group of hazard. An influence of exfoliations on material properties depends significantly on the type of the stressed state. Compression strength of exfoliated material may essentially decrease depending on occurrence depth and length of the exfoliation.
Cracks are attributed to the third hazard group of defects. Cracks create a high concentration of stresses, break integrity of a composite material by subjecting it and its separate elements to environmental attacks.
Local zones with a raised content of fibers, matrix or pores belong to the fourth group of defects. The hazard degree of such defects depends, finally, on size, shape and arrangement of a defect.
Folds, striae, cavities, foreign particles, crumples, joints and overlappings of reinforcing filler are ascribed to the fifth hazard group. Joints and overlappings basically influence on physical-mechanical characteristics through a change of material structure. Crumples, folds, striae and foreign particles have a very similar effect on physical-mechanical properties of materials.
Spalling of edges of holes and pockets, tearing of surface layers, chips and holes are included in the sixth hazard group because they are stress concentrators reducing load-bearing ability of materials.
The defects referred to the fiber curvature in the layer plane and to an insignificant deviation of the reinforcement angle from a preset value belong to the seventh hazard group.
Acoustic, radiation (X-ray), thermal, radio wave, optical and other tech-niques of nondestructive testing are applied to detect macro-defects in PCM constructions.
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P4
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Inspection Options for Detecting Various Types of Impact Damage in Composite Structures
D. Roach, R. Duvall, S. Neidigk, T. Rice, Sandia National Laboratories, Albuquerque, USA
Abstract:
Aircraft structures made from polymer-matrix composites are vulnerable to damaged created by impact...
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Abstract: minimize
Aircraft structures made from polymer-matrix composites are vulnerable to damaged created by impact from ground vehicles/equipment, as well as from events such as hail and bird strikes. These impacts can create internal damage that is not visually detectable and thus of great concern from a damage tolerance and safety standpoint. The focus of this study is on the detection of damage stemming from a variety of impact types and the relationship between inspection capabilities and the damage resistance of carbon/epoxy tape laminates. Panels of varying thicknesses were impacted with a variety of impactors (hardened, hail, bumpers) where the input energy was derived from both high velocity-low mass and low velocity-high mass scenarios. Impact location was also varied in order to study the effect on substructure elements. Different nondestructive inspection (NDI) methods were applied to damage stemming from impacts in the vicinity of the failure threshold energies (FTE) of these composites. FTE is defined as the minimum amount of energy required to create initial delamination damage in the structure. Relationships between failure threshold velocity and the ratio of panel thickness to impactor diameter were determined and the sensitivities of multiple nondestructive inspection (NDI) methods were intercompared. NDI testing included both hand-held A-scan or meter response methods, as well as wide area C-scan mapping techniques. Rapid, “Go/No-Go” NDI devices were assessed to establish the viability of using gate-check inspections on in-service aircraft to identify damage of concern. The inspection portion of this impact study seeks to determine the ability of conventional and advanced NDI to detect hidden impact damage that is at or below the level referred to as Barely Visible Impact Damage (BVID). This study will allow flaw detection to be adequately judged based on the effects of impact on the structural integrity of composites. It will aid maintenance engineers in assessing whether an incident could have caused damage to a structure, and if so, what type of inspection technique should be applied to resolve the extent of damage.
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P5
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Estimation of Probability of Detection Curves Based on Theoretical Simulation of the Inspection Process
L. Zhao, C. Carpentier, R.M. Sanderson, C. Schneider, TWI, Cambridge, UK
Abstract:
Estimation of probability of detection (POD) curves by NDT typically relies on the manufacture of l...
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Abstract: minimize
Estimation of probability of detection (POD) curves by NDT typically relies on the manufacture of large numbers of realistic defect specimens, followed by practical trials of the inspection procedure. These are costly and time consuming activities. POD curves could be generated more rapidly and more cost-effectively if theoretical simulation of PODs were shown to be sufficiently representative of actual inspection performance.
This paper compares the predictions of two such simulation-based POD models with pre-existing evidence from EDF Energy’s Capability Statement for manual ultrasonic testing (UT). One of the models is an in-house software tool called PODPEDGE, which calls the EDF Energy code PEDGE. The other POD tool is part of the CIVA code developed by CEA.
Overall the PODs predicted by both tools were consistent with pre-existing evidence. Where like-for-like comparisons were possible, there was also remarkably good agreement between them. In many respects, the CIVA software offers broader functionality than the PODPEDGE tool, eg different materials and component geometries. However, PODPEDGE has the advantage of faster run-times and can therefore produce more accurate point estimates of POD (within a specified run-time). PODPEDGE also includes an internal estimate of model accuracy, based on error flags available within the PEDGE code.
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P6
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Improving the Reliability of Automated Non-Destructive Inspection
N. Brierley, The Manufacturing Technology Centre, Coventry, UK
P. Cawley, T. Tippetts, Imperial College London, UK
Abstract:
Automated data acquisition is increasingly common in industrial NDE, driving a recent multiple incr...
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Abstract: minimize
Automated data acquisition is increasingly common in industrial NDE, driving a recent multiple increase in the availability of data. The data analysis remains a mostly manual task, performed by a skilled operator - a rather painstaking task given that much of data contains no indications. Partial automation, using software to prioritise regions of interest, could simultaneously increase inspection reliability and decrease data analysis time, by optimising the use of the operator’s time. The project set out to produce such a software system general enough to fit a wide array of NDE applications, focussing on two specific examples: the ultrasonic inspection of power station rotor bores and the ultrasonic immersion inspection of aerospace titanium turbine discs. The paper presented reviews the progress made, identifies some of the obstacles encountered and demonstrates the developed capabilities using example software outputs.
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P7
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Systematic Evaluation of CT Scanners
S. Amrhein, M. Kaloudis, M. Rauer, Hochschule Aschaffenburg, Germany
Abstract:
Since the beginning of the usage of X-ray computer tomography (CT) in industry particularly for rel...
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Abstract: minimize
Since the beginning of the usage of X-ray computer tomography (CT) in industry particularly for reliability and quality testing, the question of performance, reliability and significance of the several different CT systems comes up. Considering different performances, resolutions and inspection volumes it gets more and more difficult for the user to make the best choice for his application.
Beside the measurement technology the testing technology is an increasing area X-ray CT is used for. For the detection of voids, impurities and inhomogeneities in materials such as plastics and metals it is essential to know the limits of the system with respect to the application.
Though until now the well-known probability of detection (POD) method is only used in safety-related or very critical tasks this method is applicable to characterise the detection performance of CT scanners. In the case of X-ray CT under certain conditions it is possible to use the hit/miss method of POD theory.
A new procedure is introduced, which allows to determine the limits of detection ability of CT scanners by means of the POD method. For this purpose a new test specimen has been developed in which well-defined defect sizes in the range from 40 µm to 200 µm have been positioned. As bulk materials aluminum and stainless steel have been used. First POD curves have been gained after inspecting the test specimen using a µ-CT scanner.
This procedure allows comparing on the market available CT measuring and analysing systems and providing a method to find out, which defect size is overlooked by the CT system used and which defect sizes can be found.
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P8
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3D Ultrasonic NDE of the Spot Welds in Automotive Industry
E. Jasiuniene, L. Mazeika, V. Samaitis, Kaunas University of Technology, Kaunas, Lithuania
R.M. Sanderson, TWI, Cambridge, UK
Abstract:
Spot welds are widely used in the automotive industry to join sheets of metal. Dimensions of the sp...
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Abstract: minimize
Spot welds are widely used in the automotive industry to join sheets of metal. Dimensions of the spot weld nugget determine the strength of the welded joint; therefore it is important to determine the actual nugget diameter and to check its integrity. Ultrasonic non-destructive evaluation of spot welds has been used for many years; however destructive methods are still used due to their higher reliability.
The most popular ultrasonic NDE method for testing spot welds is manual pulse-echo using conventional probes. The evaluation of the spot weld is done by analyzing the resultant A-scans. In this case, reliability of the inspection is affected by selection of the correct probe diameter and accurate positioning of the probe in the centre of the spot weld. In manual pulse echo testing, in order to determine if nugget is of correct size, the diameter of the probe must be approximately equal to the smallest allowable weld diameter. Also it is very important to position the probe in the centre of the spot weld. If the selected probe is too big or not correctly centred, the weld will be evaluated as bad because of occurrence of intermediate echoes in the A-scan.
The application of the 2D matrix array for the spot weld testing would overcome these problems. The selection of the correct probe diameter and positioning of the probe in the centre of the spot weld becomes less important, because the ultrasonic array could reconstruct the 3D image of the spot weld, if advanced signal processing techniques are used.
The objective of this work was to develop the signal processing algorithm, which would enable the reconstruction of a 3D spot weld image from the full matrix capture data collected using a 2D ultrasonic matrix array. For this, an enhanced total focusing method was used. The proposed signal processing algorithm was verified using the finite element model of a good weld, and two types of bad welds - an undersized weld and the weld with the pore.
The obtained results show that use of the 2D matrix array for non-destructive evaluation of the spot welds allows reconstruction of the 3D spot weld image and could be used to check the reliability of the conventional spot weld testing.
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P9
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Reliability Considerations for Emerging Digital Radiography Standards & Practices
L. Schaefer, Blue Origin, Kent, USA
Abstract:
As the conversion in Industrial Radiographic imaging from film to digital continues, new constraint...
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Abstract: minimize
As the conversion in Industrial Radiographic imaging from film to digital continues, new constraints & sources of variation are introduced which touch IC, HF and AP components of our comprehensive NDE reliability equation. Hence we ask the question, what does good look like in a digital world. This paper will review published and emerging ASTM, ISO, EN, standards & practices, from both an equivalence and an optimization perspective. Producibility of the controls and metrics will be also examined in the context of detection reliability for human and automated interpretations.
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P10
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Decomposition of Residual Joint Line Conditions in Solid State Welding for PAUT Reliability Measurement
L. Schaefer, Blue Origin, Kent, USA
Abstract:
Solid state welding has given the Aerospace industry many advantages over fusion welding since its ...
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Abstract: minimize
Solid state welding has given the Aerospace industry many advantages over fusion welding since its introduction in the 1990s. It has also created its own set of unique integrity assessment challenges. In order to correctly size the structures for basic strength and lifecycle dynamics we need to be able to quantify the performance of NDE, or eNDE. Ideally this performance will be mapped to different levels of strength and related joint bond conditions. This presentation looks at solid state welded structures and attempts to establish a transfer function for PAUT and other NDE. A proposal is made on how to define the residual joint line condition, and estimate total bond at the lower bound of material properties.
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P11
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Review of ASTM E2862, Practice for Probability of Detection Analysis for Hit/Miss Data for Proto EC Exams of Weldments
L. Schaefer, Blue Origin, Kent, USA
Abstract:
Recently "practical" standards and practices have been released which attempt to distill the parent...
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Abstract: minimize
Recently "practical" standards and practices have been released which attempt to distill the parent guideline: MIL-HNBK-1823A, to a more "user friendly" format. Concerns are raised, especially in the area of experimental design, as to whether practices such as E2862 will adequately control the quality of reliability data. This presentation examines a case history in eddy current examination of welds where the outcome of 2862 is compared against the 1823A. The gap analysis will provide recommendations for improved controls in the ASTM practice.
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P12
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Implementing NDE Technology and Effective Integration to a US Highway Agency Bridge Management Program
H. Aktan, Western Michigan Univ., Kalamazoo, USA
H. Wiggenhauser, BAM, Berlin, Germany
U. Attanayake, Western Michigan Univ., Kalamazoo, USA
Abstract:
The state trunkline system managed by the Michigan Department of Transportation (MDOT) comprised of...
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Abstract: minimize
The state trunkline system managed by the Michigan Department of Transportation (MDOT) comprised of 9,695 miles and carries 51 percent of total statewide traffic. There are 4,413 bridges on the trunkline and 40 percent is on freeways. Total bridge deck area maintained by the MDOT is 49 million square feet (i.e., 75 percent of the bridge deck area of all Michigan’s highway bridges). Michigan has eleven corridors on National/International significance. The decision principles to guide the management, operation, and investments on these corridors include strategies to reduce delays and minimize impacts during inspection as well as construction. One of the strategies explored by MDOT is to incorporate and integrate NDE technologies to bridge management.
The authors were charged for organizing a workshop for MDOT engineers and administrators for understanding the state of the practice NDE technologies. The goal of the workshop was to provide technology transfer to MDOT staff regarding the effective implementation of readily available and proven NDE technology, and how NDE is most effectively integrated into the specific components of the bridge management program. The workshop presentations would focus on those NDE technologies that have been successfully used by other Highway Agencies, and the advantages and drawbacks of a particular technology. Presentations include specific examples of how the NDE was used as part of a successful bridge management program; the level of difficulty or specialized training needed for operation and data interpretation; and lessons learned.
The article will discuss the outcome of the workshop including MDOT administrators’ and engineers’ reliability expectations. The article will also describe the road map to NDE technology integration to the highway agency bridge management program.
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P13
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Pipeline Girth Welds Inspection Using Automated Ultrasonic Testing (AUT) with Zonal Discrimination – Simulation of POD Curves Using CIVA Software
B. Chapuis, CEA LIST, Gif-sur-Yvette, France
F. Jenson, SAFRAN, Magny Les Hameaux Cedex, France
L. Pomié, Technip France, Paris La Défense, France
G. Di Crisci, J. Hamilton, Technip UK, Westhill, UK
Abstract:
The inspection of pipeline girth welds can be performed by automated ultrasonic testing systems com...
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Abstract: minimize
The inspection of pipeline girth welds can be performed by automated ultrasonic testing systems composed of several channels (different transducers or multi-element probes with a set of different focal laws). These systems allow, with a single scan along the circumference of the pipe, a complete examination of the weld using the zonal discrimination approach. However, the use of these systems is subjected to the demonstration of their performances confronted to realistic degradations of their environment. This demonstration is synthesized in a qualification dossier and is supported by experimental sensitivity analysis to several influencing factors (pipe temperature, error in the positioning of the sensors…) and POD curves determination. This requires a large amount of experiments.
In order to reduce the cost and time required today to determine a POD curve for a given inspection method simulation can be used.
Simulations of typical girth welds inspection configurations using CIVA software are performed. Many influencing factors can be taken into account in CIVA such as the material and geometry of the specimen, the location, orientation and geometry of the flaw, the orientation and wedge geometry of the probe. Uncertainty propagation is performed using a Monte Carlo sampling strategy to get POD curves. In accordance to the DNV recommended practices a cumulative lognormal distribution is used to approximate POD curves based on Hit/Miss data. Purely numerical POD curves can therefore be obtained for a single channel and for the global inspection system. The whole computation scheme to get the numerical POD curves using CIVA software and its dedicated POD module will be presented. The possibility to merge simulated data with experimental data is also evoked.
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P14
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Qualification Status of NDT Technologies for Main Primary Component PSI in the Olkiluoto 3 New EPR Power Plant
J. Laube, G. Guse, Framatome, Erlangen, Germany
Abstract:
Before application of remote controlled ultrasonic (UT) and eddy current (ET) inspections a rigorou...
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Abstract: minimize
Before application of remote controlled ultrasonic (UT) and eddy current (ET) inspections a rigorous qualification programm must be applied. For the Olkiluoto 3 EPR, the qualification of systems, procedures and personnel is done in accordance with the ENIQ methodology.
The qualification project team consists of experts from different nationalities including France, Finland and Germany.
Approximately 26 different qualifications have been performed and documented under this program for Olkiluoto 3. This presentation will provide information, highlights and experiences of this extensive qualification project for the main primary EPR components. Moreover the qualification process improvements, lessons learned, and overview of the advanced tooling that has been developed and verified in course of these works will be discussed particularly addressing:
- Scope of inspection
- Provisions made to facilitate In-Service Inspections (ISI) on the primary components of
OL-3
- Co-operation between supplier, inspection body, licensee, qualification body and the Finnish authority
- Qualification process in accordance to YVL 3.8 which is the Finnish implementation of ENIQ methodology
- Qualification procedure
- Examples of achieved qualifications
- Gain of experiences and development of sophisticated tooling
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P15
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Precise Inspection Results are Leading to Longer Inspection Intervals Due to the Use of Phased Array and Analysis Techniques (e.g. SAFT) Using the Example of Hollow-Bored Axles and Shafts
N. Schmarje, Framatome, Erlangen, Germany
F. Wolfsgruber, Actemium Cegelec, Nürnberg, Germany
G. Engl, Erlangen, Germany
D. Bröckl, E. Zaus, Framatome, Erlangen, Germany
Abstract:
The demand for higher detection sensitivity and greater analysis precision has grown in the last ye...
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Abstract: minimize
The demand for higher detection sensitivity and greater analysis precision has grown in the last years. One example from the railway industry addresses the direct link between sensitivity for cracks and the inspection interval. If the inspection systems are more sensitive, techniques may be implemented to allow improved differentiation between real flaws such as cracks in the base material versus false indications such as road stone in the paint layer. At the same time, simple, quick and user-friendly acquisition and analysis of inspection data is necessary to allow high inspection productivity while minimizing or eliminating improper interpretations by human analysts responsible for the review of inspection results. Improper interpretations may be first safety relevant and second very costly, if repairs or replacement of the tested parts are initiated. The continuing effort to avoid these issues has spurred more and more automation in both acquisition and data analysis.
In many cases the Phased Array technique solves some of these challenges. To be able to use different incident angles helps to differentiate between real flaws or echoes generated by the inspection part geometry. If an angle sweep is acquired during scanning it is also possible to do a SAFT reconstruction to enhance the data allowing clearer representations of any detected flaws. This was done in one of the examples that will be presented. The task was to detect a ligament in a U groove seam within a BWR CRDM housing. Using a specially designed Phased Array probe and SAFT, AREVA was able to clearly size the ligament and justify leaving the component in service.
The second example is the inspection of hollow axles for the railway industry. To overcome the apparent conflict of high detection sensitivity and no false calls, AREVA invented a new inspection technique which combines the advantages of conventional UT probes that are optimized for detection and Phased Array probes that are optimized for sizing and SAFT reconstructions.
The applications are all supported by a UT system with advanced software that enables a high degree of automation.
By realizing these features, justification to increase the time between inspections and thereby reduce costs overall are realized.
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P16
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Probability of Detection of Ultrasonic In-Service Inspection of Hollow Axles
M. Carboni, Politecnico di Milano, Italy
C. Gilardoni, Gilardoni, Mandello del Lario, Italy
S. Cantini, Lucchini RS, Lovere, Italy
S. Beretta, Politecnico di Milano, Italy
Abstract:
Hollow axles, widely employed in High Speed and Very High Speed railways applications, are typicall...
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Abstract: minimize
Hollow axles, widely employed in High Speed and Very High Speed railways applications, are typically inspected by the ultrasonic testing method applied using a suitable boreprobe roto-translating along the longitudinal bore. Different ultrasonic transducers, emitting shear waves at 2-4 MHz and at different refraction angles in steel, are used to inspect the whole external surface of the axle in order to individuate cracks and defects at press-fit seats and at the body, especially along geometrical transitions. The structural integrity of the wheel-set is then based, together with other factors, on the efficient and reliable determination of the Probability of Detection (POD) curve of the boreprobe. For a given probes configuration, the POD curve is function of UT equipment, its calibration and its inspection parameters, therefore the same UT equipment could develop different POD curves as a function of the operating procedure normally defined by wheel-set manufacturers or end users. It is then important to split the absolute performances of the UT equipment by the different performances obtainable with different calibration and operation procedures. In order to derive such curves, a statistically representative sample of natural defects is needed.
For this purpose, ten full-scale hollow axles, made of a quenched and tempered alloyed railway steel, were fatigue tested using a dedicated bench in order to develop two natural fatigue cracks in each of them. Different artificial defects were also introduced on the external surface on one of the axles by EDM. A total set of 28 semi-circular defects (17 natural and 11 artificial) was then obtained in a range of depths from 0.4 mm to 12 mm. Such a set allowed the experimental derivation of the POD curve of the boreprobe following the “signal response” approach. A general analysis of different calibration method leads to a comparison between different POD obtainable with the same UT inspecting device. A final part of the research consisted in the optimization of the boreprobe itself, by means of suitable numerical simulations, in terms of frequency, dimension of the transducer, angle of refraction and location of the defect/crack.
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P17
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Evaluation of the Reliability of Ultrasonic Testing Russian Railway Transport
V. Konshina, University of a Railway Transportation, St. Petersburg, Russia
A. Shevelev, Inst. for bridges & NDT, St. Petersburg, Russia
G. Dymkin, University of a Railway Transportation, St. Petersburg, Russia
Abstract:
Algorithms to estimate ultrasonic testing method based on the integrated use of indicators of relia...
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Abstract: minimize
Algorithms to estimate ultrasonic testing method based on the integrated use of indicators of reliability and accuracy, and built according to the nature of techniques, features of their application and evaluation purposes (comparison techniques, the introduction of new methods, containing test procedures, etc.). On the basis of the main provisions of ISO 5725-1, 5725-2 the estimate reproducibility and repeatability of measured characteristics determine the design of reflectors and real defects and reliability of non-destructive, including ultrasonic inspection of railways
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P18
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Observer POD for Radiographic Testing
D. Kanzler, Applied Validation of NDT, Berlin, Germany
C. Müller, BAM, Berlin, Germany
M. Bertovic, Berlin, Germany
J. Pitkänen, Posiva, Eurajoki, Finland
Abstract:
The radiographic testing is an important non-destructive testing method, especially in industrial a...
more
Abstract: minimize
The radiographic testing is an important non-destructive testing method, especially in industrial areas where people could be injured in case of failing of a component. There it is a mighty method to find volumetric defects. As bigger the penetrated length of the defect in the component is, as bigger is the radiographic contrast. The detectability of volumetric defects in its turn is not only depending on the contrast but also on the noise, the defect area and its shape, . The currently applied POD approach uses mostly only the contrast and the noise as detection threshold. This does not reflect accurately the results of evaluations by human observers. A new approach is introduced, using the widely applied POD evaluation and additionally a detection threshold depending on the area of the defect. The presentation shows the process of calculating the POD curves with simulated data by the modeling software aRTist and with artificial reference data. This approach was developed within a joint project with the company POSIVA, which is constructing a final depository for high active nuclear fuels in Finland. Radiographic testing is one of the NDT-methods they use to test the electron beam welds of the copper canisters. The copper canisters will be used in the depository as a corrosion barrier within the waste management concept.
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P19
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Economic Assessment and Modelling of Inspection Using the Inspection Value Method (IVM) – How POD Adds Value and Reduces Risk
M. Wall, ESR Technology, Abingdon, UK
Abstract:
Inspection plays a vital role in manufacturing quality control and plant maintenance but managers a...
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Abstract: minimize
Inspection plays a vital role in manufacturing quality control and plant maintenance but managers are increasingly aware that economy both in manufacture and plant management are vital to competitive success.
The Inspection Value Method (IVM) is a decision making tool and cost-benefit method for assessment of inspection that crucially takes into account the performance and reliability (POD, false calls) of the NDE method. Key cost drivers such as access, inspection, mitigation and consequential costs can be included. On this basis, different inspection options can be properly compared, and the added-value and risk reduction arising from the inspection quantified.
Originally developed in the UK National NDT Centre at Harwell in the early 1990s, the IVM method can be used at a high level as a strategic tool, for example to optimise the inspection strategy for a pipeline network; or at a more detailed level to optimise inspection parameters such as coverage, the threshold and sensitivity used, to select the best NDE method (s), or to demonstrate the value of introducing a new or more reliable inspection method.
The paper describes the IVM approach and model, showing the importance of POD and false calls to the value of inspection. A number of practical examples are included to illustrate the benefits including inspection of a subsea pipeline, optimising coverage in ship hull inspection, and detecting localised damage mechanisms such as in Microbially induced corrosion (MIC) or corrosion under insulation (CUI).
The examples show that the value and risk reduction arising from inspection is dependent on a number of key drivers including the inspection reliability (POD, false calls), performance parameters including coverage, speed and sensitivity and the number and spatial distribution of defects present.
A very similar method has been applied in the US aerospace industry to aid introduction of new inspection technology. The method can be combined with time-dependent models or historical reliability data to optimise the inspection interval,quality and frequency of inspection.
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P20
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Damage Localization via Transmissibility Power Mode Shape
Y.L. Zhou, R. Perera, Technical University of Madrid, Spain
Abstract:
Damage localization plays an increasingly important role in structural health monitoring of numerou...
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Abstract: minimize
Damage localization plays an increasingly important role in structural health monitoring of numerous engineering applications. In order to achieve this goal, many methods have been developed relating to the dynamic features between the healthy and damaged statuses. Especially the variation of natural frequencies and mode shapes data have been undertaken investigation.
Transmissibility has been of continuing interest to the scientific communities in recent years and became a well studied topic due to its property that only depends on the output signal.
In this paper a method of damage localization by using transmissibility power mode shape is proposed. Above all, transmissibility is implemented in the frequency domain from the output data measurements after choosing a reference point. Then, average transmissibility to different reference points would be calculated. Consequently, transmissibility power mode shape is constructed via the transmissibility as to a particular point apart from the boundary points. Henceforth, modal parameters and damage localization indices are generalized to analyze the structural properties and identify as well as localize the damages under different loading conditions. Finally, the Gaussian white noise is added into the numerical simulation to illustrate the feasibility of the proposed damage localization parameters in engineering applications. Experimental results confirm the excellent performances of the method not only able to detect and localize damage but also to assess different damage levels.
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P22
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What are the Influencing Factors on Inspection Performance of UT Testing on the Wheel Set Hollow Axle in the Context of Education and Brush Up Examination?
T. Heckel, BAM, Berlin, Germany
D. Kanzler, Applied Validation of NDT, Berlin, Germany
T. Dobberphul, C. Müller, M. Rosenthal, BAM, Berlin, Germany
M. Bertovic, Berlin, Germany
R. Holstein, DGZfP Ausbildung und Training, Berlin, Germany
F. Sondermann, DGZfP Ausbildung und Training, Wittenberge, Germany
Abstract:
About 500 examination results of manual UT testing on hollow axles of wheel sets with artificial an...
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Abstract: minimize
About 500 examination results of manual UT testing on hollow axles of wheel sets with artificial and natural flaws were compared with a sophisticated phased array reference investigation and the mechanical measured flaw data and evaluated statistically. The aim of the investigation is to improve the training and the set up of examinations. The POD and the variance of echo amplitudes are analyzed with respect to the parameters of the ultrasonic probe used and the age and experience of the inspectors and also the number of recertification examination. The future investigation should focus on the factors, identified during this investigation, which influence the inspection quality and decrease variation in the inspection results, as well as provide with recommendations on how to improve the education of the operating personnel. A comparison of results from manual and mechanized testing of the wheel sets hollow axles provides a hint how to make this type of testing more reliable.
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P23
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Investigation of Multiple Parameter Influences on the POD of Mechanized UT-Testing
T. Dobberphul, R. Boehm, T. Heckel, C. Müller, M. Rosenthal, BAM, Berlin, Germany
J. Pitkänen, Posiva, Eurajoki, Finland
U. Ronneteg, SKB, Oskarshamn, Sweden
Abstract:
For long-term storage of spent nuclear fuel in Sweden and Finland SKB and Posiva has developed a ca...
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Abstract: minimize
For long-term storage of spent nuclear fuel in Sweden and Finland SKB and Posiva has developed a canister consisting of a nodular cast iron insert surrounded by a copper shell. Non-destructive testing of the canister components is crucial to verify that each canister will contain the required properties. In order to determine the reliability of developed NDT techniques POD studies have been done for some of the developed phased array ultrasonic techniques based on data from artificial defects like flat-bottom and side-drilled holes. The POD calculation formulas have been adapted to take into account the influence of the variations in inspection depth and the complex phased array ultrasonic properties like; frequency, focus depth, time gain corrected amplitudes etc. Specially, has the complex interaction of the sound wave with the material properties in the test specimen been accounted for. The features of the method are presented and the results are discussed
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P25
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Improvements in Post-Processing of Signals Acquired from a Lambwaves Based SHM System for Detecting Corrosion in Aluminum Plates
B.J. Guilheme de Aragão, T.F. de Abreu Santos, V.A. de Assis, P.H. de Oliveira Lopes, A. Fernandes Mazoni, R.F. Larico Chavez, E. Sanches Silva, CPqD, Campinas, Brazil
Abstract:
This work presents a technique to detect corrosion comprised of PZT sensors attached on aluminum pl...
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Abstract: minimize
This work presents a technique to detect corrosion comprised of PZT sensors attached on aluminum plates and a technique of signal analysis. Corrosion is related to mass loss, represented by a circular damage with depths in the range of 0.04 mm to 0.5 mm on a 300x200x2 mm aluminum plate. In order to eliminate several types of interference and to compare signals from non damaged and damaged plates, correlation techniques and wavelet transform analysis is used. The characteristics of the Lambwave signals are: scattering, time of flight and others estimated from time signals (The frequencies used are 100, 150, 370 kHz). The established correlation function helps to identify the intensity of the artificial damage (depth) with the aid of algorithms on the behavior of the scales wavelet transform. This approach provides satisfactory initial preliminary results on artificial damage detection in aluminum plates.
Proposed research:
Currently the problem found during the post-processing of data is the low sensitivity of conventional techniques for small amounts of mass loss. Furthermore, it is necessary to carry out a statistical validation of the SHM system. The response signals can include additional reflections from borders.
One way to solve the problem described above is by improving the sensitivity of the system response, followed by signal processing of the results. Data processing with wavelet and other wavelet training techniques improves system response based on a baseline (damage free) and a known answer (damage of known size). To validate the system, i.e., to verify if the improvement does not cause destabilization, the POD 90/95 curve is determined using the experimental results, with and without improvement.
The objective of this part of the work is to investigate and develop a mathematical post-processing method of the data obtained with aluminum plates, including: Determination and application of wavelet decomposition and relating them to the discontinuities for improve system response. Development of a control module for training. Damage location using blind search and investigation of search algorithms to find variations in the wavelet scales. Finding out sizes and appropriate thresholds for the system under investigation and for small mass losses
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P26
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Towards the Integration of a Knowledge-Based Approach in SHM
I. Buethe, F. Ansari, M. Fathi, C.-P. Fritzen, Y. Niu, Universität Siegen, Germany
Abstract:
Structural Health Monitoring (SHM), as a method to monitor structures continuously, is gaining incr...
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Abstract: minimize
Structural Health Monitoring (SHM), as a method to monitor structures continuously, is gaining increasing interest in the NDE community. In its basic form, it aims to detect one defined kind of damage in the area of inspection. Additional levels also perform the localization and classification of damages as well as the damage assessment and prediction. To achieve damage prognosis, attempting to forecast system performance, it is e.g. necessary to measure in some way the current loading (usage monitoring) on the structure and estimate the future loading environment as well as to use a damage evolution model. This way the remaining useful life can be predicted. Many SHM systems are currently using only one specific source of information to extract knowledge regarding the structure’s state. Moreover the output of many SHM systems tends to be black or white, often not taking into account uncertainties. This limits the reliability performance of these systems. In the area of Knowledge Management (KM) there are already many available techniques which may perform the reasoning under uncertainty and the decision-making by using different knowledge technologies and information sources. Such approaches incorporate technological risks e.g. constraints on software or hardware development, and non-technological risk associated with economic factors of SHM e.g. cost, present value, and return on investment. Those risk parameters have an influence on maintenance programs, the advancement of SHM systems, and ultimately on decision-making. This contribution proposes to integrate the systematic approaches from KM into the SHM study in order to improve the reliability of SHM systems.
Via data management and the combined use of multiple algorithms, already used in the SHM community, in a knowledge-based decision making toolbox, it is possible to achieve a higher level of information. In such a way, it fosters optimal usage of SHM algorithms developed for different aims, and therefore improve the reliability of the analysis result. Furthermore this concept also may help to push the SHM study forward to more practical usages and promote the condition-based maintenance.
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