1、Designation: E2001 18Standard Guide forResonant Ultrasound Spectroscopy for Defect Detection inBoth Metallic and Non-metallic Parts1This standard is issued under the fixed designation E2001; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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. Scope*1.1 This guide describes a procedure for detecting defects inmetallic and non-metallic parts using th
3、e resonant ultrasoundspectroscopy method. The procedure is intended for use withinstruments capable of exciting and recording whole bodyresonant states within parts which exhibit acoustical or ultra-sonic ringing. It is used to distinguish acceptable parts fromthose containing defects, such as crack
4、s, voids, chips, densitydefects, tempering changes, and dimensional variations that areclosely correlated with the parts mechanical system dynamicresponse.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard doe
5、s 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This internation
6、al standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committ
7、ee.2. Referenced Documents2.1 ASTM Standards:2E1316 Terminology for Nondestructive ExaminationsE1876 Test Method for Dynamic Youngs Modulus, ShearModulus, and Poissons Ratio by Impulse Excitation ofVibrationE2534 Practice for Process Compensated Resonance TestingVia Swept Sine Input for Metallic and
8、 Non-Metallic PartsE3081 Practice for Outlier Screening Using Process Com-pensated Resonance Testing via Swept Sine Input forMetallic and Non-Metallic Parts3. Terminology3.1 DefinitionsThe definitions of terms relating to conven-tional ultrasonics can be found in Terminology E1316.3.2 Definitions of
9、 Terms Specific to This Standard:3.2.1 resonant ultrasonic spectroscopy (RUS), na nonde-structive examination method, which employs resonant ultra-sound methodology for the detection and assessment of varia-tions and mechanical properties of a test object. In thisprocedure, whereby a rigid part is c
10、aused to resonate, theresonances are compared to a previously defined resonancepattern. Based on this comparison the part is judged to be eitheracceptable or unacceptable.3.2.2 swept sine method, nthe use of an excitation sourceto create a transient vibration in a test object over a range offrequenc
11、ies. Specifically, the input frequency is swept over arange of frequencies and the output is characterized by aresonant amplitude response spectrum.3.2.3 impulse excitation method, nstriking an object witha mechanical impact, or electromagnetic field (laser and/orElectromagnetic Acoustic Transducer
12、(EMAT) causing mul-tiple resonances to be simultaneously stimulated.3.2.4 resonant inspection (RI), nany induced resonantnondestructive examination method employing an excitationforce to create mechanical resonances for the purpose ofidentifying a test objects conformity to an established accept-abl
13、e pattern.4. Summary of the Technology (1)34.1 Introduction:4.1.1 In addition to its basic research applications inphysics, materials science, and geophysics, Resonant Ultra-sound Spectroscopy (RUS) has been used successfully as an1This guide is under the jurisdiction of ASTM Committee E07 on Nondes
14、truc-tive Testing and is the direct responsibility of Subcommittee E07.06 on UltrasonicMethod.Current edition approved Nov. 1, 2018. Published November 2018. Originallyapproved in 1998. Last previous edition approved in 2013 as E2001 - 13. DOI:10.1520/E2001-18.2For referenced ASTM standards, visit t
15、he 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 the list of references at the end ofthis guide.*A Summ
16、ary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established
17、 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.1applied nondestructive testing tool. Resonant ultrasound spec-troscopy in commercial, nondestructive testing ha
18、s a fewrecognizable names including, RUS Nondestructive Testing,Acoustic Resonance Spectroscopy (ARS), Resonant Inspection(RI) and Process Compensated Resonance Testing (PCRT).Early references to this body of science often are termed the“swept sine method.” It was not until 1990 (2) that the nameRes
19、onant Ultrasound Spectroscopy appeared, but the twotechniques are synonymous. Additionally, impulse methods,like the striking of a rail car wheel with a hammer, andlistening for the responses, have been used for over 100 yearsto detect the existence of large cracks. RUS based techniquesare commonly
20、used to evaluate metallic and nonmetallicmaterial and finished parts made from a variety of processesincluding casting, forging, sintering, machining and additivemanufacturing. In these situations, a part is vibratedmechanically, and defects are detected based on changes in thepattern of resonances
21、or variations from analytically or numeri-cally calculated or measured acceptable spectra. RUS measuresall resonances of the part in a defined frequency range ratherthan scanning for individual defects. In a single measurement,RUS-based techniques can test for numerous defects includingcracks, chips
22、, cold shuts, inclusions, voids, posority, oxides,contaminants, missed processes or operations, and variations indimension, hardness, porosity, nodularity, density, and heattreatment. Since the RUS measurement yields a whole-bodyresponse, it is often difficult to discriminate between defecttypes. Th
23、e technique is effective for detecting parts withstructural anomalies, but less effective for diagnosing the exactlocation or cause of an anomaly within a part. Nevertheless, foran expansive range of parts RUS provides accurate, fast,quantitative and cost-effective results that require no humanjudgm
24、ent, making 100 % examination of a part populationpossible. Many theoretical texts (3) discuss the relationshipbetween resonances and elastic constants and include thespecific application of RUS to the determination of elasticconstants (4). The technology received a quantum increase inattention when
25、 Migliori published a review article, includingthe requisite inexpensive electronic designs and proceduresfrom which materials properties could be measured quicklyand accurately (5). The most recent applications includestudies in ultrasonic attenuation, modulus determinations, ther-modynamic propert
26、ies, structural phase transitions, supercon-ducting transitions, magnetic transitions, and the electronicproperties of solids. A compendium of these applications maybe found in the Migliori (1) text. Resonant ultrasound spec-troscopy also found use in the study of the elastic properties ofthe Apollo
27、 moon rocks (6).4.1.2 This guide is intended to provide a practical introduc-tion to RUS-based nondestructive testing (NDT), highlightingsuccessful applications and outlining failures, limitations, andpotential weaknesses. Vibrational resonances are consideredfrom the perspective of defect detection
28、 in 4.2.In4.3 and 4.4,a review of some of the types of RUS measurements are givenand 4.6 examines the common practice of using the impulseexcitation method. In 4.6, some example implementations andconfigurations of RUS systems and their applications arepresented. Finally, the guide concludes with a
29、discussion ofconstraints, which limit the effectiveness of RUS.4.2 Mode Shapes and Defects:4.2.1 Resonant ultrasound spectroscopy/NDT techniques,operate by driving a part at given frequencies and measuring itsmechanical response (Fig. 1 contains a schematic one embodi-ment of a RUS apparatus). The p
30、rocess proceeds in smallfrequency steps over some previously determined region ofinterest. During such a sweep, the drive frequency typicallybrackets a resonance. When the excitation frequency is notmatched to one of the parts resonance frequencies, very littleenergy is coupled to the part; that is,
31、 there is little mechanicalvibration. At resonance, however, the energy delivered to thepart is coupled generating much larger mechanical vibrations.A parts resonance frequencies are determined by the standarddynamic equations of motion, which include variables formass, stiffness, and damping. The m
32、ass, stiffness, and dampingproperties are determined by geometry, density, and materialelastic constants of the part. The required frequency windowand data collection parameters for a scan depend on the partgeometry, mass, material properties, and the characteristics ofthe defects of interest.4.2.2
33、Exciting a part at its resonance frequencies will causethe part to deform in an array of patterns that correspond toFIG. 1 Schematic of the Essential Electronic Building Blocks to Employ RUS in a Manufacturing EnvironmentE2001 182different frequencies. These deformation patterns are calledmode shape
34、s. Bending, torsional (twisting) and extensional(breathing) modes are common shapes in simple geometrieslike cylinders. More complex and/or localized variations onthese shapes will be excited in more complex geometries. Alarge enough frequency range excited by either a swept sine orimpulse input wil
35、l excite multiple harmonics of the same modeshape (first bending mode, second bending mode, and so on).Fig. 2 shows an example of mode shapes excited in a portionof the resonance spectra for a basic cylinder. Modes 7 and 8 area pair of degenerate bending modes (see 4.3.4.1 for a descrip-tion of dege
36、nerate modes). Mode 9 is a torsional mode. Mode10 is an extensional mode. Modes 11 and 12 are the nextharmonic of the bending mode. Mode 13 is the next harmonicof the torsional mode.4.2.3 Different mode shapes have varying sensitivities togeometric variations, material state variations, and flaws in
37、parts. Knowledge of the mode shape helps to determine whatqualities of the part affect those frequencies. The resonancefrequencies of a part correlate directly to its stiffness (resis-tance to deformation). Reducing the part stiffness by reducingthe relevant elastic constant lowers the associated re
38、sonantfrequency for most modes. If a defect, such as a crack, isintroduced into a region under strain, it will reduce theeffective stiffness in that area and cause a downward shift ofthe frequency of resonant modes that introduce strain at thecrack. For example, a crack may reduce the ability of the
39、 partto resist twisting, thereby reducing the effective stiffness andfrequency of a torsional mode. Geometric variations also affectresonance modes to varying degrees. For example, increasingthe length of a cylinder will lower resonant frequencies ofbending modes more than torsional or extensional m
40、odes.Torsional modes in a cylinder remain constant for fixed length,independent of diameter variation. Variation in the size of agiven defect also changes which modes are affected and themagnitude of that effect. A large defect can be detected readilyby its effect on the first few modes. Smaller def
41、ects have moresubtle effects on stiffness, requiring higher frequencies (high-order modes) to be detected. Detection of very small defectsmay require using the frequency corresponding to the fiftieth,or even higher, mode. In the cylinder example, some modes donot produce strain in the end of the cyl
42、inder, therefore, theycannot detect end defects. To detect this type of defect, a morecomplex mode is required, the description of which is beyondthe scope of this specification.Adefect in the cylinder end willreduce the effective stiffness for this type of mode, and thus,will shift downward the fre
43、quency of the resonance. In general,it must be remembered that most modes will exhibit complexmotions, and for highly symmetric objects, can be linearcombinations of several degenerate modes, as discussed in4.3.2.4.3 General Approaches to RUS/NDT:4.3.1 Test Evaluation Methods (1)Once a fingerprint h
44、asbeen established, for conforming parts, numerous algorithmscan be employed to either accept or reject the part. Forexample, if a frequency 650 Hz can be identified for allconforming parts, the detection of a peak outside of thisboundary condition will cause the computer code to signal a“test rejec
45、t” condition. The code, rather than the inspector,makes the accept/reject decision. The following sections willexpand on some of these sorting criteria.4.3.2 Frequency Shifts:4.3.2.1 Resonant ultrasound spectroscopy measurementsgenerally produce strains (even on resonance) that are wellwithin the el
46、astic limit of the materials under test, that is, theatomic displacements are small in keeping with the “nonde-structive” aspect of the testing. If strains are applied above theelastic limit, a crack will tend to propagate, causing a mechani-cal failure. Note that certain important engineering prope
47、rties,for example, the onset of plastic deformation, yield strength,etc., generally are not derivable from low-strain elastic prop-erties. Sensitivity of the elastic properties of an object to thepresence of a crack depends on the stiffness and geometry ofthe sample under test. This concept is expan
48、ded upon under4.4.3.4.3.2.2 Fig. 3 shows an example of the resonance spectrumfor a conical ceramic part. Several specific types of modes areFIG. 2 Examples of Modes of Vibration Matched to Their Peaks in a Resonance SpectrumE2001 183present in this scan, and their relative shifts could be used todet
49、ect defects as discussed above; however, the complexity issuch that, for NDT purposes, some selections must be made sothat only a portion of such a large amount of information isused. For simple part geometries, the mode type and frequencycan be calculated, and selection of diagnostic modes can bebased on these results. For complex geometries, empiricalapproaches have been developed to identify efficiently diag-nostic modes for specific defects. In this process, a technicianmeasures the spectra for a batch of known good and bad parts.The spectra are compared to identify
