1、Designation: E 1065 99 (Reapproved 2003)Standard Guide forEvaluating Characteristics of Ultrasonic Search Units1This standard is issued under the fixed designation E 1065; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers measurement procedures for evaluat-ing certain characteristics of ultrasonic search units (alsokno
3、wn as “transducers”) that are used with ultrasonic exami-nation instrumentation. This guide describes means for obtain-ing performance data that may be used to define the acousticand electric responses of ultrasonic search units.1.2 The procedures are designed to measure search units asindividual co
4、mponents (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 incomi
5、ng inspection 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
6、search unit evaluation. Annex A8 describes a guidefor measuring sound beam profiles in metals from contactstraight-beam search units. Additional Annexes, such as soundbeam profiling for angle-beam search units in metal andalternate means for search unit characterization, will be addedwhen developed.
7、1.5 The values stated in inch-pound units are to be regardedas standard.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 t
8、he applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 1316 Terminology for Nondestructive Examinations22.2 Other Document:Standard Methods for Testing Single Element Pulse-EchoUltrasonic Transducers33. Terminology3.1 DefinitionsFor definitions of terms
9、used in this guide,see Terminology E 1316.3.2 Definitions of Terms 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 frequencyresponse that falls within
10、given limits. In this text, the limitsused are the -6 dB level, as measured from the peak of thefrequency response. The equation used for BW is:BW 5 fu2 f1!/fc3 100 (1)where:fu= upper frequency,f1= lower frequency, andfc= center frequency.Bandwidth is expressed as a percentage.3.2.3 center frequency
11、 (fc)the frequency value calculatedto be at the center of the bandwidth 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 len
12、s to the focal point.3.2.6 focal point (Fp)for focused search units, 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.3.2.7 frequency responsethe pulse-echo response of thesearch unit measured as a
13、function of frequency. (This termalso referred to as frequency spectrum.)3.2.8 nominal frequency (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)th
14、e frequency value at themaximum amplitude of the frequency response.1This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-tive Testing and is the direct responsibility of Subcommittee E07.06 on UltrasonicMethod.Current edition approved July 10, 2003. Published September 2003. Ori
15、ginallyapproved in 1985. Last previous edition approved in 1999 as E 1065 99.2Annual Book of ASTM Standards, Vol 03.03.3Available from the American Institute of Ultrasonics in Medicine, 14750Sweitzer Lane, Suite 100, Laurel, MD 20707-5906.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
16、C700, West Conshohocken, PA 19428-2959, United States.3.2.11 pulse durationthe 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 appli
17、ed voltage with the amplitude of thepulse-echo voltage recorded from a specified 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
18、of measurements madealong a line perpendicular to the acoustic axis of the 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
19、or echo (for example, 20or 40 dB).4. Summary of Guide4.1 The acoustic and electrical characteristics which can bedescribed from the data obtained by procedures outlined in thisguide are described as follows:4.1.1 Frequency ResponseThe frequency response maybe obtained from one of two procedures: (a)
20、 shock excitationand (b) sinusoidal burst. Annex A1 describes procedures 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 sensi
21、tivity may be obtained from the frequencyresponse data obtained using 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.
22、Annex A3 describes the procedure forobtaining pulse-echo sensitivity.NOTE 1Values for applied and received power, from which insertionloss might be determined are not covered with procedures described in thisguide.4.1.3 Time ResponseThe time response provides a meansfor describing the radio frequenc
23、y (rf) response of the wave-form. A shock excitation, pulse-echo 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)
24、. Annex A4 describes theprocedures for measuring time response.4.1.4 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
25、the impedance ofthe search unit over the operating frequency range 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 c
26、omplexelectrical impedance may also be obtained using values re-corded from the sinusoidal burst techniques as outlined inAnnex A5.4.1.4.2 d-c ResistanceThe d-c resistance of the searchunit may provide information regarding the electrical tuningelements. Measurements are made across the terminals of
27、 theunit.4.1.5 Sound Field MeasurementsThe objective of thesemeasurements is to establish parameters such as the on-axisand transverse sound beam profiles for immersion flat andfocused search units.4.1.5.1 Annexes A6 and A8 of this guide describe ways formaking sound field measurements for both imme
28、rsion flat andfocused search units in water and contact straight-beam searchunits in metal. The literature discusses several ways for makingthese measurements, but the techniques described are relativelysimple and easily performed.4.1.5.2 Means are recommended for making measurementsin an immersion
29、tank, thereby allowing either pulse-echo (balltarget) or 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 sou
30、nd beam patternsare intended to define limits of performance. 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. Se
31、veral potential approachesare being considered, but have not yet gained subcommittee agreement(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. Therecor
32、ding or line drawing shows only the positive component 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 guide is intended to provide standardized
33、proce-dures for evaluating ultrasonic search units. 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.5
34、.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 guide to specify, describe, or provide a perfor-mance criteria for procurement and quality assurance, orservice evaluation of the ope
35、rating characteristics of ultrasonicsearch units. All or portions of the guide may be used asdetermined by the user.4The boldface numbers in parentheses refer to a list of references at the end ofthis test method.E 1065 99 (2003)25.5 The measurements are made primarily under pulse-echoconditions. To
36、 determine the relative performance of a searchunit as either a transmitter or a receiver may require additionaltests.5.6 While these procedures relate to many of the significantparameters, others that may be important in specific applica-tions may not be treated. These might include power handlingc
37、apability, 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 guide follow similarprocedures. The conditions specified or selected (if optional)may affect the tes
38、t results and lead to apparent differences.FIG. 1 Test Data Available from Shock Excitation ProcedureFIG. 2 Test Data Available from Sinusoidal Burst TechniqueE 1065 99 (2003)35.8 Interpretation of some test results, such as the shape ofthe frequency response curve, may be subjective. Small irregu-l
39、arities may be significant. Interpretation of the test results isbeyond the scope of this guide.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 experime
40、nt or the electrical characteristicsof the 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
41、 erroneous results may result.6. Typical Results 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
42、 response may be obtained.6.2 Fig. 2 illustrates 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
43、data recorded with this tech-nique.7. Keywords7.1 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 FREQUE
44、NCY RESPONSEA1.1 IntroductionThe frequency 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 peak
45、frequency, center frequency (see Annex A1), bandwidth (seeAnnex A2) and sensitivity (see Annex A3). 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 which
46、the frequency response is asymmetrical.A1.1.1 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
47、impedance, search unit impedance, pulseshape, and measurement systems. The measurement system tobe used for search unit evaluation should be established byusers of the guide.A1.2 Shock Excitation TechniqueThe shock excitationtechnique for obtaining frequency response is based on theprinciple that a
48、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 typicalcompone
49、nts used to measure frequency response of an rfanalog waveform. The system consists of a search unit, shockpulse generator (pulser), preamplifier (receiver), electronic gatethat can be adjusted to capture the echo waveform, displayoscilloscope, and spectrum analyzer. Fig. A1.3 describes typi-cal components used to measure the frequency response of adigitized rf waveform. The system consists of a search unit,pulser, receiver, gate that can be adjusted to capture the echowaveform, analog to digital converter (digitizer), Fouriertransform calculator, and di
