1、Designation: E2534 15Standard 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 detect resonance pattern differences in metallicand non-metallic parts. The resonance differences can be usedto distinguish acceptable parts with normal process variationfrom parts with material states and defects that will causeperformance deficiencies. These m
4、aterial states and defectsinclude, 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.
5、This practice is intended 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 This practice uses inch pound units as primary units. SIunits are included i
6、n parentheses for reference only, and aremathematical conversions of the primary units.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 safety and health practices
7、and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1316 Terminology for Nondestructive ExaminationsE2001 Guide for Resonant Ultrasound Spectroscopy forDefect Detection in Both Metallic and Non-metallic Parts3. Terminology3.1 Definition
8、s:The definitions of terms relating to conventional ultrasonicexamination can be found in Terminology E1316.3.2 Definitions of Terms Specific to This Standard:3.2.1 broadbandthe range of frequencies, excitationparameters, and data collection parameters developed specifi-cally for a particular part t
9、ype.3.2.2 classificationthe labeling of a teaching set of parts asacceptable or unacceptable.3.2.3 false negative, npart failing the sort but deemed byother method of post-test/analysis to have acceptable or con-forming specifications3.2.4 false positive, npart passing the sort but exhibiting aflaw
10、(either inside the teaching set of flaws or possibly outsidethe teaching set range of flaws) or nonconforming to specifi-cation.3.2.5 margin parta single part representative of a part typethat is used to determine measurement repeatability and forsystem verification.3.2.6 Process Compensated Resonan
11、t Testing (PCRT)anondestructive examination method that enhances RUS withpattern recognition capability. PCRT more effectively discrimi-nates between resonance frequency shifts due to unacceptableconditions from resonance frequency shifts due to normal,acceptable manufacturing process variations. Th
12、e process em-ploys the measurement and analysis of acoustic or ultrasoundresonance frequency patterns, or both. PCRT pattern recogni-tion tools identify the combinations of resonance patterns thatmost effectively differentiate acceptable and unacceptablecomponents. Statistical scoring of the resonan
13、ce frequencies isused to compare components to known acceptable and unac-ceptable populations, quantify process variation, and charac-terize component populations.3.2.7 resonance spectrathe recorded collection of reso-nance frequency data, including frequency peak locations andthe characteristics of
14、 the peaks, for a particular part.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 Dec. 1, 2015. Published December 2015. Originallyapproved in 2010. Last pre
15、vious edition approved in 2010 as E2534-10.DOI: 10.1520 E2534-152For referenced ASTM standards, 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 websi
16、te.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.8 Resonant Ultrasound Spectroscopy (RUS)BasicRUS (1)3was originally applied in fundamental researchapplications in physics and materials science. Other recogniz-able names include
17、 acoustic resonance spectroscopy, acousticresonant inspection, and resonant inspection. Guide E2001documents RUS extensively. RUS is a nondestructive exami-nation method that employs the measurement and analysis ofacoustic or ultrasonic resonance frequencies, or both, for theidentification of accept
18、able variations in the physical charac-teristics of test parts in production environments. In thisprocedure an isolated, rigid component is excited, producingoscillation at the natural frequencies of vibration of thecomponent. Diagnostic resonance frequencies are measuredand compared to resonance fr
19、equency patterns previouslydefined as acceptable. Based on this comparison, the part isjudged to be acceptable or, if it does not conform to theestablished pattern, unacceptable.3.2.9 sorta software program capable of classifying acomponent as acceptable or unacceptable.3.2.10 teaching seta group of
20、 like components includingexamples of known acceptable and known unacceptable com-ponents representative of the range of acceptable variabilityand unacceptable variability.3.2.11 work instructionstepwise instructions developedfor each examination program detailing the order and applica-tion of opera
21、tions 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 detect structuralanomalies that significantly alter component performance. Thedetails of this basic form of resonance testi
22、ng are outlined inGuide 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,application of RUS for production NDT led to better
23、under-standing of the challenges associated with differentiatingresonance variations caused by structural anomalies fromresonance variation from normal and acceptable process varia-tions in mass, material properties, and dimensions (2,3). PCRTfirst became commonly used in the production examination
24、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 sinewave to excite the components through a range of resonancefrequencies determined by the parts mass,
25、 geometry, andmaterial properties. The resonance spectrum is then comparedto resonance spectra for known acceptable components andunacceptable components. The database of known acceptableand unacceptable components is established through the col-lection of a teaching set of components that represent
26、 the rangeof acceptable process variation and the unacceptable conditionsof interest. PCRT applications are taught to be sensitive toresonance variations associated with unacceptable componentsand also taught to be insensitive to variations associated withacceptable components. PCRT pattern recognit
27、ion tools iden-tify the combination of resonance frequencies that most effec-tively differentiate the acceptable and unacceptable compo-nents. Statistical tools score each component based on itssimilarity to the known acceptable and unacceptablepopulations, and establish scoring PASS/FAIL limits for
28、 eachcriteria. A component with resonance frequencies sufficientlysimilar to the acceptable components and different from theunacceptable components will pass the PCRT inspection. Acomponent that fails either criteria will be rejected. In oneexamination cycle, PCRT-based techniques can test for a si
29、ngleanomaly, or for combinations of anomalies, as listed in 1.1. ThePCRT measurement yields a whole body response, findingstructurally-significant anomalies anywhere within the part, butit is generally not capable of determining the type or locationof the anomaly. A teaching set of parts must contai
30、n bothacceptable and unacceptable samples as determined by some-one knowledgeable of the design, validation testing, andminimum functional requirements of the part.4.1.4 PCRT can be applied to new parts in the productionenvironment, to parts currently in service, or in a combinedprogram in which par
31、ts 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. One exampleof a PCRT application is gas turbine engine blades.Applicationof PCRT to the blades in
32、the production environment can detectmanufacturing and material defects such as casting shrinkage,cracks, voids, shifted cores, heat treatment irregularities, andother material variation. Since turbine blades are periodicallyinspected throughout their useful lives, PCRT can be appliedduring these in
33、-service inspections to accept only parts that arefree of service induced defects such as gamma primesolutioning, rafting, creep, cracks, inter-granular attack, andexcessive wear and fatigue.4.1.5 This practice is intended to provide a practical guide tothe application of PCRT-based nondestructive t
34、esting (NDT) tometallic and non-metallic parts. It highlights the steps neces-sary to produce robust and accurate test applications andoutlines potential weaknesses, limitations and factors thatcould lead to misclassification of a part. Some basic explana-tions of resonances, and the effects of anom
35、alies 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,respectively. Additionally, some constraints and limitations arediscussed in 5.3. The general
36、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 (acoustic throughultrasonic, depending on the part characteristics) and measur-ing i
37、ts mechanical response. Fig. 1 contains a schematic for one3The boldface numbers in parentheses refer to a list of references at the end ofthis practice.E2534 152embodiment of a PCRT apparatus. The swept sine waveproceeds in small frequency steps over a previously determinedbroadband frequency range
38、 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 is coupled, generating much largervibrations.Aparts resonan
39、ce 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.4.2.2 If a structural anomaly, such as a crack, is introducedi
40、nto 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 decreasing stiff-ness). Voids in a region can reduce mass and increa
41、se 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 effects of various anomalies onresonances are presented in Guide
42、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 constantfor a fixed length, independent of diameter.Acrack w
43、ill 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 s
44、ame 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, and therefore, often require higher frequencies (high-order resonant modes and harmonic
45、s) to be detected. Ingeneral, it must be remembered that most parts will exhibitcomplex motions when resonating. Analyzing the relationshipbetween the resonant frequencies provides one way to generatethe information necessary to interpret the data resulting frommeasuring the frequencies of the vario
46、us resonant modes.These relationships form one basis for detecting the differencebetween normal, expected variations and variations indicatingsignificant structural or geometric differences from one part toanother. A broad body of research is available describingvarious other nonproprietary approach
47、es to identifying signifi-cant features (flaws, damage, etc) from changes in theirvibration characteristics in the presence of environment orprocess variation.(6)5. Significance and Use5.1 PCRT Applications and CapabilitiesPCRT has beenapplied successfully to a wide range of NDT applications in them
48、anufacture 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,aerospace, and power generation. Examples of successfulapplications curren
49、tly employed in commercial use include,but are not limited to:(1) Silicon nitride bearing elements(2) Steel, iron, and aluminum rocker and control armsFIG. 1 PCRT System SchematicFIG. 2 Resonance Spectra (50 kHz 120 kHz) FIG. 3 Torsional Mode for CylinderE2534 153(3) Gas turbine engine components (blades, vanes, disks)(4) Cast cylinder heads and cylinder blocks(5) Sintered powder metal gears and clutch plates(6) Machined forged steel steering and transmission com-ponents (gears, shafts, racks)(7) Ceramic oxygen sensors(8) Silicon wafers(9) Gears with induction ha
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