1、Designation: E3081 16Standard Practice forOutlier Screening Using Process Compensated ResonanceTesting via Swept Sine Input for Metallic and Non-MetallicParts1This standard is issued under the fixed designation E3081; the number immediately following the designation indicates the year oforiginal ado
2、ption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes a general procedure for using theprocess compen
3、sated resonance testing (PCRT) via swept sineinput method to perform outlier screening on populations ofnewly manufactured and in-service parts. PCRT excites theresonance frequencies of metallic and non-metallic test com-ponents using a swept sine wave input over a set frequencyrange. PCRT detects a
4、nd analyzes component resonance fre-quency patterns, and uses the differences in resonance patternsbetween acceptable and unacceptable components to performnon-destructive testing. PCRT frequency analysis compares theresonance pattern of a component to the patterns of knownacceptable and unacceptabl
5、e populations of the samecomponent, and renders a pass or fail result based on thesimilarity of the tested component to those populations. Fornon-destructive testing applications with known defects ormaterial states of interest, or both, Practice E2534 covers thedevelopment and application of PCRT s
6、orting modules thatcompare test components to known acceptable and unaccept-able component populations. However, some applications donot have physical examples of components with known defectsor material states. Other applications experience isolated com-ponent failures with unknown causes or causes
7、 that propagatefrom defects that are beyond the sensitivity of the currentrequired inspections, or both. In these cases, PCRT is appliedin an outlier screening mode that develops a sorting moduleusing only a population of presumed acceptable productioncomponents, and then compares test components fo
8、r similarityto that presumed acceptable population. The resonance differ-ences can be used to distinguish acceptable components withnormal process variation from outlier components that mayhave material states or defects, or both, that will causeperformance deficiencies. These material states and de
9、fectsinclude, but are not limited to, cracks, voids, porosity, shrink,inclusions, discontinuities, grain and crystalline structuredifferences, density-related anomalies, heat treatmentvariations, material elastic property differences, residual stress,and dimensional variations. This practice is inte
10、nded for usewith instruments capable of exciting, measuring, recording,and analyzing multiple, whole body, mechanical vibrationresonance frequencies in acoustic or ultrasonic frequencyranges, or both.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parenth
11、eses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate
12、safety and health practices and determine the applica-bility of regulatory limitations prior to use. Some specifichazards statements are given in Section 7 on Hazards.2. Referenced Documents2.1 ASTM Standards:2E1316 Terminology for Nondestructive ExaminationsE2001 Guide for Resonant Ultrasound Spect
13、roscopy forDefect Detection in Both Metallic and Non-metallic PartsE2534 Practice for Process Compensated Resonance TestingVia Swept Sine Input for Metallic and Non-Metallic Parts3. Terminology3.1 Definitions:3.1.1 The definitions of terms relating to conventionalultrasonic examination can be found
14、in Terminology E1316.3.2 Definitions:3.2.1 broadband, nthe range of frequencies, excitationparameters, and data collection parameters developed specifi-cally for a particular part type.3.2.2 classification, nthe labeling of a teaching set of partsas acceptable or unacceptable.1This test method is un
15、der the jurisdiction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.06 onUltrasonic Method.Current edition approved Dec. 1, 2016. Published December 2016. DOI:10.1520/E308116.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or
16、contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international s
17、tandard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.
18、2.3 false negative, npart failing the sort but deemed byother method of post-test/analysis to have acceptable or con-forming specifications.3.2.4 false positive, npart passing the sort but exhibiting aflaw (either inside the teaching set of flaws or possibly outsidethe teaching set range of flaws) o
19、r nonconforming to specifi-cation.3.2.5 margin part, na single part representative of a parttype that is used to determine measurement repeatability andfor system verification.3.2.6 Process Compensated Resonant Testing (PCRT),nPCRT is a nondestructive examination method that en-hances RUS with patte
20、rn recognition capability. PCRT moreeffectively discriminates resonance frequency shifts due tounacceptable conditions from resonance frequency shifts dueto normal, acceptable manufacturing process variations. Theprocess employs the measurement and analysis of acoustic orultrasonic resonance frequen
21、cy patterns, or both. PCRT patternrecognition tools identify the combinations of resonance pat-terns that most effectively differentiate acceptable and unac-ceptable components. In outlier screening applications, statis-tical scoring of the resonance frequencies is used to comparecomponents of the p
22、resumed acceptable population, quantifyprocess variation, and characterize component populations.3.2.7 quality factor (Q factor), ndimensionless propertyof resonance peak that describes the peak shape, that is, widthrelative to the peak center frequency; peaks with higher Qfactor values are narrower
23、 and sharper.3.2.8 resonance spectra, nthe recorded collection of reso-nance frequency data, including frequency peak locations andthe characteristics of the peaks, for a particular part.3.2.9 Resonant Ultrasound Spectroscopy (RUS), nBasicRUS was originally applied in fundamental research applica-ti
24、ons in physics and materials science (1)3. Other recognizablenames include acoustic resonance spectroscopy, acoustic reso-nant inspection, and resonant inspection. Guide E2001 docu-ments RUS extensively. RUS is a nondestructive examinationmethod that employs the measurement and analysis of acoustico
25、r ultrasonic resonance frequencies, or both, for the identifi-cation of acceptable variations in the physical characteristics oftest parts in production environments. In this procedure anisolated, rigid component is excited, producing oscillation atthe natural frequencies of vibration of the compone
26、nt. Diag-nostic resonance frequencies are measured and compared toresonance frequency patterns previously defined as acceptable.Based on this comparison, the part is judged to be acceptableor, if it does not conform to the established pattern, unaccept-able.3.2.10 sort, nfor outlier screening applic
27、ations, a softwareprogram capable of classifying a component as acceptable oroutlying.3.2.11 teaching set, nfor outlier screening applications, agroup of like components including examples of only pre-sumed acceptable production components representative of therange of acceptable variability.3.2.12
28、work instruction, nstepwise instructions developedfor each examination program detailing the order and applica-tion of operations for PCRT examination of a part.4. Summary of Practice4.1 Introduction:4.1.1 Many variations on resonance testing have been ap-plied as nondestructive examination tools to
29、 detect structuralanomalies that significantly alter component performance. Thedetails of this basic form of resonance testing are outlined inGuide E2001.4.1.2 Process Compensated Resonance Testing (PCRT) is aprogressive development of the fundamental principles ofRUS, and can employ various methods
30、 for enhancing thediscrimination capability of RUS. Throughout the 1990s,application of RUS for production NDT led to better under-standing of the challenges associated with differentiatingresonance variations caused by structural anomalies fromresonance variations from normal and acceptable process
31、variation in mass, material properties and dimensions (2), (3).PCRT first became commonly used in the production exami-nation of metal and ceramic parts in the late 1990s (4). By theearly 2000s, PCRT had essentially developed into the robustNDT capability it is today (5).4.1.3 PCRT is a comparison t
32、echnology using a swept sinewave to excite the components through a range of resonancefrequencies determined by the parts mass, geometry, andmaterial properties. In outlier screening applications, the reso-nance spectrum is then compared to resonance spectra forpresumed acceptable components. The da
33、tabase of presumedacceptable components is established through the collection ofa teaching set of components that represent the range ofacceptable process variation. PCRT outlier screening applica-tions are taught to be insensitive to variations associated withacceptable components and identify reso
34、nance variations thatindicate outlier components. PCRT outlier screening can useZ-score statistical analysis of frequencies for a large number ofresonance modes to determine frequency averages and fre-quency deviation and set limits for each value. A componentthat exceeds either the frequency averag
35、e or frequency devia-tion limits is flagged as outlier. PCRT outlier screening can alsouse pattern recognition and statistical scoring using theMahalanobis-Taguchi System (MTS) to evaluate a test com-ponent for similarity to the training population using a smallernumber of resonance modes. A compone
36、nt that exceeds theMTS-based limits is flagged as an outlier. In one examinationcycle, PCRT-based outlier screening can identify outlier partsthat may contain a single anomaly or combinations ofanomalies, as listed in 1.1. The PCRT measurement yields awhole body response, finding structurally-signif
37、icant anoma-lies anywhere within the part, but it is generally not capable ofdetermining the type or location of the anomaly.4.1.4 PCRT outlier screening can be applied to new parts inthe production environment, to parts currently in service, or ina combined program in which parts are initially clas
38、sified as3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.E3081 162free of substantial anomalies in production, and then periodi-cally re-examined with PCRT in order to monitor for theaccumulation of fatigue and damage resulting from use. Oneexample of a
39、PCRT outlier screening application is gas turbineengine blades. Outlier screening is used to detect materialanomalies and conditions resulting from out-of-control manu-facturing processes for new production blades. For in-serviceblades, outlier screening detects unexpected side effects fromrepair pr
40、ocesses and non-repairable conditions from in-serviceaging/damage.4.1.5 This practice is intended to provide a practical guide tothe application of PCRT-based outlier screening to metallic andnon-metallic parts. It highlights the steps necessary to producerobust and accurate test applications and ou
41、tlines potentialweaknesses, limitations and factors that could lead to misclas-sification of a part. Some basic explanations of resonances, andthe effects of anomalies on them, are found in 4.2. Somesuccessful applications and general description of the equip-ment necessary to successfully apply PCR
42、T for classification ofproduction parts are outlined in 5.1 and 5.2, respectively.Additionally, some constraints and limitations are discussed in5.3. The general procedure for developing a part-specific PCRTapplication is laid out in 6.1.4.2 Resonance and the Effect of Anomalities:4.2.1 The swept si
43、ne method of vibration analysis operatesby driving a part at given frequencies (acoustic throughultrasonic, depending on the part characteristics) and measur-ing its mechanical response. Fig. 1 contains a schematic for oneembodiment of a PCRT apparatus. The swept sine waveproceeds in small frequency
44、 steps over a previously determinedbroadband frequency range of interest. When the excitationfrequency is not matched to one of the parts resonancefrequencies, very little energy is coupled to the part; that is,there is essentially no vibration. At resonance, however, theenergy delivered to the part
45、 is coupled, generating much largervibrations.Aparts resonance frequencies are determined by itsgeometry, density, and material elastic constants (mechanicallyequivalent to mass, stiffness, and damping) of the material. Anexample of the resonance spectra for a part is shown in Fig. 2for reference.4.
46、2.2 If a structural anomaly, such as a crack, is introducedinto a region under strain, it will change the effective stiffnessof a part (decrease stiffness for a crack). That is, the partsresistance to deformation will change and will shift some of theparts resonant frequencies (downward for decreasi
47、ng stiff-ness). Voids in a region can reduce mass and increase certainresonant frequencies. In general, any change to a part that altersthe structural integrity, changes a geometric feature or affectsthe material properties will alter its natural resonance frequen-cies. Graphic examples of the effec
48、ts of various anomalies onresonances are presented in Guide E2001.4.2.3 For example, the torsional (twisting) (Fig. 3) resonantmodes represent a twisting of a part about its axis. In the simpleexample of a long cylinder, these resonances are easilyidentified because some of their frequencies remain
49、constantfor a fixed length, independent of diameter.Acrack will reducethe ability of the part to resist twisting, thereby reducing theeffective stiffness, and thus, the frequency of a torsional modeboth shifts to a lower value and then alters the mode shape.Other resonances representing different resonance mode shapesof the part will not be affected in the same manner.Also, a largestructural anomaly can be detected readily by its effect on thefirst few resonant frequencies. However, smaller structuralanomalies have much more subtle and localized effects onstiffness,
