1、Designation: E1065/E1065M 14Standard Practice forEvaluating Characteristics of Ultrasonic Search Units1This standard is issued under the fixed designation E1065/E1065M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers measurement procedures for evalu-ating certain characteristics of ultrasonic search units (alsokno
3、wn as “probes”) that are used with ultrasonic testinginstrumentation. This practice describes means for obtainingperformance data that may be used to define the acoustic andelectric responses of ultrasonic search units.1.2 The procedures are designed to measure search units asindividual components (
4、separate from the ultrasonic test instru-ment) using commercial search unit characterization systemsor using laboratory instruments such as signal generators,pulsers, amplifiers, oscilloscopes, and waveform analyzers.1.3 The procedures are applicable to manufacturing accep-tance and incoming inspect
5、ion of new search units or toperiodic performance evaluation of search units throughouttheir service life.1.4 The procedures in Annex A1 Annex A6 are generallyapplicable to ultrasonic search units operating within the 0.4 to10 MHz range. Annex A7 is applicable to higher frequencyimmersion search uni
6、t evaluation. Annex A8 describes apractice for measuring sound beam profiles in metals fromcontact straight-beam search units. Additional Annexes, suchas sound beam profiling for angle-beam search units in metaland alternate means for search unit characterization, will beadded when developed.1.5 The
7、 values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the sta
8、ndard.1.6 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 and determine the applica-bility of regulatory limitations prior to use.2. Refere
9、nced Documents2.1 ASTM Standards:2E1316 Terminology for Nondestructive Examinations2.2 Other Document:Standard Methods for Testing Single Element Pulse-EchoUltrasonic Transducers33. Terminology3.1 DefinitionsFor definitions of terms used in thispractice, see Terminology E1316.3.2 Definitions of Term
10、s Specific to This Standard:3.2.1 aperturethe dimension(s) of the active area of thepiezoelectric element of the search unit as established byexperimentation.3.2.2 bandwidth (BW) that portion of the frequency re-sponse that falls within given limits. In this text, the limits usedare the -6 dB level,
11、 as measured from the peak of the frequencyresponse. The equation used for BW is:BW 5 fu2 f1!/fc3100 (1)where:fu= upper frequency,f1= lower frequency, andfc= center frequency.Bandwidth is expressed as a percentage.3.2.3 center frequency (fc)the frequency value calculatedto be at the center of the ba
12、ndwidth limits.3.2.4 depth of field (FD)as measured on the on-axis profileof a focused search unit, that portion of the sound beam thatfalls within given limits.3.2.5 focal length (FL)for focused search units, the dis-tance from the lens to the focal point.3.2.6 focal point (Fp)for focused search un
13、its, the pointalong the acoustic axis of the beam in water at which the peak(maximum) pulse-echo amplitude response is recorded from aball target reflector.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.0
14、6 onUltrasonic Method.Current edition approved Jan. 1, 2014. Published February 2014. Originallyapproved in 1985. Last previous edition approved in 2008 as E1065 08. DOI:10.1520/E1065_E1065M-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s
15、erviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the American Institute of Ultrasonics in Medicine, 14750Sweitzer Lane, Suite 100, Laurel, MD 20707-5906.*A Summary of Changes section appears at the en
16、d of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.7 frequency responsethe pulse-echo response of thesearch unit measured as a function of frequency. (This termalso referred to as frequency spectrum.)3.2.8 nominal f
17、requency (fnom)the frequency stated on thelabel supplied by the manufacturer.3.2.9 on-axis profilea sequence of measurements madealong the acoustic axis of the beam of the search unit.3.2.10 peak frequency (fp)the frequency value at themaximum amplitude of the frequency response.3.2.11 pulse duratio
18、nthe length of the sinusoidal burstused to excite the search unit as expressed in time or numberof cycles (sometimes referred to as tone-burst).3.2.12 pulse echo sensitivitya measurement that comparesthe amplitude of the applied voltage with the amplitude of thepulse-echo voltage recorded from a spe
19、cified target.3.2.13 shock excitationa short electrical impulse that isapplied to the search unit. The impulse is typically a negative-going voltage spike of fast rise time and short duration.3.2.14 transverse profilesequence of measurements madealong a line perpendicular to the acoustic axis of the
20、 beam ofthe search unit.3.2.15 waveform durationthe time interval or durationover which the unrectified signal or echo from a specifiedtarget exceeds a selected amplitude level as related to themaximum amplitude of the signal or echo (for example, 20or 40 dB).4. Summary of Practice4.1 The acoustic a
21、nd electrical characteristics which can bedescribed from the data obtained by procedures outlined in thispractice are described as follows:4.1.1 Frequency ResponseThe frequency response may beobtained from one of two procedures: (a) shock excitation and(b) sinusoidal burst. Annex A1 describes proced
22、ures forobtaining frequency response for immersion and zero-degreecontact search units. Annex A2 describes the procedure forobtaining bandwidth characteristics.4.1.2 Relative Pulse-Echo Sensitivity (Srel)The relativepulse-echo sensitivity may be obtained from the frequencyresponse data obtained usin
23、g the sinusoidal burst proceduredescribed in Annex A1. The value is obtained from therelationship of the amplitude of the voltage applied to thesearch unit and the amplitude of the pulse-echo signal receivedfrom a specified target. Annex A3 describes the procedure forobtaining pulse-echo sensitivity
24、.NOTE 1Values for applied and received power, from which insertionloss might be determined are not covered with procedures described in thispractice.4.1.3 Time ResponseThe time response provides a meansfor describing the radio frequency (rf) response of the wave-form. A shock excitation, pulse-echo
25、procedure is used toobtain the response. The time or waveform responses arerecorded from specific targets that are chosen for the type ofsearch unit under evaluation (for example, immersion, contactstraight beam, or contact angle beam). Annex A4 describes theprocedures for measuring time response.4.
26、1.4 Electrical Impedance:4.1.4.1 Complex Electrical ImpedanceThe complex elec-trical impedance may be obtained with commercial impedancemeasuring instrumentation, and these measurements may beused to provide the magnitude and phase of the impedance ofthe search unit over the operating frequency rang
27、e of the unit.These measurements are generally made under laboratoryconditions with minimum cable lengths or external accessoriesand in accordance with the instructions of the instrumentmanufacturer. The value of the magnitude of the complexelectrical impedance may also be obtained using values re-c
28、orded from the sinusoidal burst techniques as outlined inAnnex A5.4.1.4.2 d-c ResistanceThe d-c resistance of the search unitmay provide information regarding the electrical tuning ele-ments. Measurements are made across the terminals of the unit.4.1.5 Sound Field MeasurementsThe objective of thesem
29、easurements is to establish parameters such as the on-axisand transverse sound beam profiles for immersion flat andfocused search units.4.1.5.1 Annex A6 and Annex A8 of this practice describeways for making sound field measurements for both immersionflat and focused search units in water and contact
30、 straight-beamsearch units in metal. The literature discusses several ways formaking these measurements, but the techniques described arerelatively simple and easily performed.4.1.5.2 Means are recommended for making measurementsin an immersion tank, thereby allowing either pulse-echo (balltarget) o
31、r hydrophone receiver techniques to be followed. Thegoal is to provide measurements to evaluate the characteristicsof search units or to identify changes that may occur as afunction of time or use, or both.4.1.5.3 None of the measurements of sound beam patternsare intended to define limits of perfor
32、mance. They are designedto provide a common means for making measurements thatmay be used to define the initial and inservice performance.NOTE 2No procedure is given for measuring sound beam profilecharacteristics for angle-beam search units. Several potential approachesare being considered, but hav
33、e not yet gained subcommittee agree-ment(1).4NOTE 3Frequency Response Displays. The frequency responses inFig. 1 and Fig. 2 and throughout the text are displayed as a linearamplitude (not logarithmic) response as a function of frequency. Therecording or line drawing shows only the positive component
34、 or envelopeof the responses. While this is the normal display for a spectrum analyzer,the sinusoidal burst response is shown as only one-half of the actualsinusoidal wave.5. Significance and Use5.1 This practice is intended to provide standardized proce-dures for evaluating ultrasonic search units.
35、 It is not intended todefine performance and acceptance criteria, but rather toprovide data from which such criteria may be established.5.2 These procedures are intended to evaluate the charac-teristics of single-element piezoelectric search units.4The boldface numbers in parentheses refer to a list
36、 of references at the end ofthis test method.E1065/E1065M 1425.3 Implementation may require more detailed proceduralinstructions in a format of the using facility.5.4 The measurement data obtained may be employed byusers of this practice to specify, describe, or provide aperformance criteria for pro
37、curement and quality assurance, orservice evaluation of the operating characteristics of ultrasonicsearch units. All or portions of the practice may be used asdetermined by the user.5.5 The measurements are made primarily under pulse-echoconditions. To determine the relative performance of a searchu
38、nit as either a transmitter or a receiver may require additionaltests.FIG. 1 Test Data Available from Shock Excitation ProcedureFIG. 2 Test Data Available from Sinusoidal Burst TechniqueE1065/E1065M 1435.6 While these procedures relate to many of the significantparameters, others that may be importa
39、nt in specific applica-tions may not be treated. These might include power handlingcapability, breakdown voltage, wear properties of contact units,radio-frequency interference, and the like.5.7 Care must be taken to ensure that comparable measure-ments are made and that users of the practice follow
40、similarprocedures. The conditions specified or selected (if optional)may affect the test results and lead to apparent differences.5.8 Interpretation of some test results, such as the shape ofthe frequency response curve, may be subjective. Small irregu-larities may be significant. Interpretation of
41、the test results isbeyond the scope of this practice.5.9 Certain results obtained using the procedures outlinedmay differ from measurements made with ultrasonic testinstruments. These differences may be attributed to differencesin the nature of the experiment or the electrical characteristicsof the
42、instrumentation.5.10 The pulse generator used to obtain the frequencyresponse and time response of the search unit must have a risetime, duration, and spectral content sufficient to excite thesearch unit over its full bandwidth, otherwise time distortionand erroneous results may result.6. Typical Re
43、sults Obtainable from Tests Described inAnnex A1 Annex A56.1 Fig. 1 illustrates some of the typical results that may beobtained using shock excitation techniques. Values for fre-quency response, peak frequency, bandwidth, bandwidth centerfrequency, and time response may be obtained.6.2 Fig. 2 illust
44、rates the typical results obtained using thesinusoidal burst technique. Values may be obtained for fre-quency response, peak frequency, bandwidth, bandwidth centerfrequency, relative pulse-echo sensitivity, and magnitude of theelectrical impedance from the data recorded with this tech-nique.7. Keywo
45、rds7.1 aperture; bandwidth; characterization; contact testing;depth of field; focal point; frequency response; immersiontesting; peak frequency; search unit; sound beam profile; timeresponse; ultrasoundANNEXES(Mandatory Information)A1. MEASUREMENT OF FREQUENCY RESPONSEA1.1 IntroductionThe frequency
46、response (also knownas frequency spectrum) is a measure of the amplitude of thepulse-echo response from a given target as a function offrequency. This response is used as the basis for establishingother operating parameters of the search unit including peakfrequency, center frequency (see Annex A1),
47、 bandwidth (seeAnnexA2) and sensitivity (see AnnexA3). Sketches of typicalresponse curves are shown in Fig. A1.1. These sketches areused to describe two conditions: (a) a response that is sym-metrical about a center frequency, and (b) a condition in whichthe frequency response is asymmetrical.A1.1.1
48、 Two means are described for obtaining the fre-quency response: (a) shock excitation, and (b) sinusoidal burst.The responses obtained using these procedures provide similarresults; however, reproducibility is dependent on factors suchas generator driving impedance, search unit impedance, pulseshape,
49、 and measurement systems. The measurement system tobe used for search unit evaluation should be established byusers of the practice.A1.2 Shock Excitation TechniqueThe shock excitationtechnique for obtaining frequency response is based on theprinciple that a shock pulse applied to the search unit producesa broad spectrum of energies and that the echo from a giventarget reflects the frequency distribution that is characteristic ofthat search unit. Measurements may be made using either theanalog or digitized rf waveform. Fig. A1.2 describes typicalco
