1、Designation: E2534 10Standard Practice forProcess Compensated Resonance Testing Via Swept SineInput for Metallic and Non-Metallic Parts1This standard is issued under the fixed designation E2534; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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 compensated resonance testing
3、 (PCRT) via swept sineinput method to identify metallic and non-metallic partsresonant pattern differences that can be used to indentify partswith anomalies causing deficiencies in the expected perfor-mance of the part in service. This practice is intended for usewith instruments capable of exciting
4、, measuring, recording,and analyzing multiple whole body mechanical vibrationresonant frequencies within parts exhibiting acoustical ringingin the audio, or ultrasonic, resonant frequency ranges, or both.PCRT is used in the presence of manufacturing processvariance to distinguish acceptable parts fr
5、om those containingsignificant anomalies in physical characteristics expected tosignificantly alter the performance. Such physical characteris-tics include, but are not limited to, cracks, voids, porosity,shrink, inclusions, discontinuities, grain and crystalline struc-ture differences, density rela
6、ted anomalies, heat treatmentvariations, material elastic properties differences, residualstress, and dimensional variations.1.2 This practice uses inch pound units as primary units. SIunits are included in parentheses for reference only, and aremathematical conversions of the primary units.1.3 This
7、 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents
8、2.1 ASTM Standards:2E1316 Terminology for Nondestructive ExaminationsE2001 Guide for Resonant Ultrasound Spectroscopy forDefect Detection in Both Metallic and Non-metallic Parts3. Terminology3.1 Definitions:The definitions of terms relating to conventional ultrasonicexamination can be found in Termi
9、nology E1316.3.2 Definitions of Terms Specific to This Standard:3.2.1 resonant ultrasound spectroscopy (RUS)Basic RUS(1)3was originally applied in fundamental research applica-tions in physics and materials science. A few other recogniz-able names include acoustic resonance spectroscopy, acousticres
10、onant inspection, and resonant inspection. Guide E2001documents RUS extensively. A nondestructive examinationmethod that employs the measurement and analysis of acous-tic, or ultrasound resonance patterns, or both, for the identifi-cation of acceptable variations in the physical characteristics ofte
11、st parts in production environments. In this procedure anisolated, rigid part is caused to resonate. Certain resonances aremeasured and compared to a previously defined acceptablepattern combination of resonances. Based on this comparison,the part is judged to be acceptable or, if it does not confor
12、m tothe established pattern, unacceptable.3.2.2 process compensated resonant testing (PCRT)anondestructive examination method which is an enhancementto RUS providing greater ability to identify resonant frequencyshifts due to flaws and unacceptable variations in componentsin the presence of acceptab
13、le resonant frequency shifts ac-countable to normal manufacturing process variations. Theprocess employs the measurement and analysis of acoustic orultrasound, or both resonance patterns for the identification ofunacceptable variations in the physical properties of examinedparts in production enviro
14、nments. In classic RUS, this proce-dure in an isolated, rigid part is caused to resonate. resonancesare measured and compared to a previously defined acceptablepattern of resonances. Based on this comparison the part isjudged to be acceptable or, if it does not conform to theestablished pattern, to
15、be, by default, unacceptable.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.06 onUltrasonic Method.Current edition approved March 1, 2010. Published March 2010. DOI: 10.1520/E2534-102For referenced ASTM s
16、tandards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthi
17、s practice.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 teaching seta group of like components includingexamples of known acceptable and known unacceptable com-ponents representative of the range of acceptable variabilityand
18、 unacceptable variability.3.2.4 sorta software program capable of classifying acomponent as acceptable or unacceptable.3.2.5 classificationthe labeling of a teaching set of partsas acceptable or unacceptable.3.2.6 false negative, npart failing the sort but deemed byother method of post test/analysis
19、 to have acceptable orconforming specifications3.2.7 false positive, npart passing the sort but exhibiting aflaw (either inside the teaching set of flaws or possibly outsidethe teaching set range of flaws) or nonconforming to specifi-cation.3.2.8 broadbandthe range of frequencies, excitation pa-rame
20、ters, and data collection parameters developed specificallyfor a particular part type.3.2.9 resonance spectrathe recorded collection of reso-nance frequency data, including frequency peak locations andthe characteristics of the peaks, for a particular part.3.2.10 work instructionstepwise instruction
21、s developedfor each examination program detailing the order and applica-tion of operations for PCRT examination of a part.3.2.11 margin parta single part representative of a parttype that is used to determine measurement repeatability andfor system verification.4. Summary of Practice4.1 Introduction
22、:4.1.1 Many variations on resonant testing have been used asan applied nondestructive examination tool in simple applica-tions discriminating structural anomalies that significantly alterperformance and are much greater than those seen in normalproduction parts as they vary in the population. The de
23、tails ofthis basic form of resonant testing are outlined in Guide E2001.4.1.2 Process compensated resonant testing (PCRT) is aprogressive development of the fundamental principles ofRUS, and can employ various methods for enhancing thediscrimination capability of RUS. Throughout the 1990s,applicatio
24、n of RUS for production NDT led to better under-standing of the challenges associated with differentiatingresonance variations caused by anomalies in a part fromresonance variations resulting from normal and acceptableprocess variations such as mass, density and dimension varia-tions within the acce
25、ptable tolerance for that part.(2), (3) PCRTfirst became commonly used in the production examination ofmetal and ceramic parts in the late 1990s.(4) By the early2000s, PCRT had essentially developed into the robust NDTcapability it is today.(5)4.1.3 PCRT is a comparison technology using a swept sine
26、wave to excite the components through a range of frequenciesdetermined by the parts mass, geometry, and material proper-ties, then recording the parts resonant responses to the sweptsine input signal. By comparing the resonance patterns ofknown acceptable components and unacceptable components,PCRT
27、applications are taught to be sensitive to resonancevariations associated with unacceptable components and alsotaught to be insensitive to variations associated with acceptablecomponents. This initial teaching phase produces a part spe-cific examination application, applying known statistical toolst
28、o the entirety of the collected spectra of the availableacceptable and unacceptable parts while determining a set ofrelationships of resonant frequencies representing patternsfound in the acceptable parts, and selecting those relationshipsspecifically excluding patterns found in the spectra of unac-
29、ceptable parts. This procedure yields a sort for examinationthat compares portions of the spectra of the part beingexamined to a set of relationships determined in the teachingphase. If the spectra of the examined component fall within anacceptance range of the acceptable pattern, then the part will
30、 beclassified as acceptable. In one examination cycle, PCRT-basedtechniques can test for a single anomaly, or for combinations ofanomalies, as listed in 1.1. The PCRT measurement yields awhole body response, finding structurally-significant anoma-lies anywhere within the part, but it is generally no
31、t capable ofdetermining the type or location of the anomaly. A teaching setof parts must contain both acceptable and unacceptablesamples as determined by someone knowledgeable of thedesign, validation testing, and minimum functional require-ments of the part.4.1.4 PCRT can be applied to new parts in
32、 the productionenvironment, to parts currently in service, or in a combinedprogram in which parts are initially classified as free ofsubstantial anomalies in production, and then periodicallyre-examined with PCRT in order to monitor for the accumu-lation of fatigue and damage resulting from use.An e
33、xample ofthe application of PCRT is given here with respect to gasturbine blades. Application of PCRT to the blades in theproduction environment can be used to accept only parts free ofmanufacturing and material defects such as cracks, voids,shifted cores, heat treatment irregularities, and the like
34、. Sinceturbine blades are periodically inspected throughout theiruseful lives, PCRT can be applied during these inspections toaccept only parts that are free of service induced defects suchas gamma prime solutioning, rafting, cracks, inter-granularattack, or excessive wear.4.1.5 This practice is int
35、ended to provide a practical guide tothe application of PCRT based nondestructive examination(NDT) to metallic and non-metallic parts. It highlights thesteps necessary to produce robust and accurate test applicationsand outlines potential weaknesses, limitations and factors thatcould lead to a parts
36、 misclassification. Some basic explana-tions of resonances, and the effects of anomalies on them, arefound in 4.2. Some successful applications and general descrip-tion of the equipment necessary to successfully apply PCRT forclassification of production parts are outlined in 5.1 and 5.2,respectivel
37、y. Additionally, some constraints and limitations arediscussed in 5.3. The general procedure for developing apart-specific PCRT application is laid out in 6.1.4.2 Resonances and the Effect of Anomalies:4.2.1 The swept sine method of vibration analysis operatesby driving a part at given frequencies (
38、audio through ultra-sound, depending on the part characteristics) and measuring itsmechanical response. Fig. 1 contains a schematic for oneembodiment of a PCRT apparatus. The process proceeds insmall frequency steps over a previously determined andE2534 102predicted range of interest. During such a
39、sweep, the drivefrequency brackets the expected location of a resonance. Whenthe excitation frequency is not matched to one of the partsresonance frequencies, very little energy is coupled to the part;that is, there is essentially no vibration.At resonance, however,the energy delivered to the part i
40、s coupled, generating muchlarger vibrations. A parts resonance frequencies are deter-mined by its geometry (to include the shape and dimensions)and by the density and the elastic constants (mechanicallyequivalent to mass, stiffness, and damping) of the material. Anexample of the resonance spectra fo
41、r a part is shown in Fig. 2for reference.4.2.2 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
42、resonant frequencies (downward for decreasing 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
43、frequen-cies. Graphic examples of the effects of various anomalies onresonances are presented in Guide E2001.4.2.3 For example, the torsional (twisting) resonant modesrepresent a twisting of a part about its axis. In the simpleexample of a long cylinder, these resonances are easilyidentified because
44、 some of their frequencies remain 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 re
45、sonances representing different resonant motions of thepart 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 onstiffnes
46、s, and therefore, often require higher frequencies (high-order resonant modes and harmonics) to be detected. Ingeneral, it must be remembered that most parts will exhibitcomplex motions when resonating and analyzing the relation-ship between the resonant frequencies provides one way togenerate the i
47、nformation necessary to interpret the data result-ing from measuring the frequencies of the various resonantmodes. These relationships form one basis for detecting thedifference between normal, expected variations and variationsindicating significant structural or geometric differences fromone part
48、to another. A broad body of research is availabledescribing various other nonproprietary approaches to identi-fying significant features (flaws, damage, etc) from changes intheir vibration characteristics in the presence of environment orprocess variation.(7)5. Significance and Use5.1 PCRT Applicati
49、ons and CapabilitiesPCRT has beenapplied successfully to a wide range of NDT applications in themanufacture and maintenance of metallic and non-metallicparts. Examples of anomalies detected are discussed in 1.1.PCRT has been shown to provide cost effective and accurateNDT solutions in many industries including automotive, aero-space, and power generation. Examples of successful applica-tions currently employed in commercial use include, but arenot limited to:(1) Silicon nitride bearing elements(2) Investment cast steel rocker arms(3) Cast gas turbine blades(4) Stam
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