1、Designation: E2904 12Standard Practice forCharacterization and Verification of Phased Array Probes1This standard is issued under the fixed designation E2904; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. 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 standard practice covers measurement proceduresfor evaluating certain characteristics of phased-array ultrasonicprobes that ar
3、e used with phased-array ultrasonic examinationinstrumentation.1.2 This standard practice describes means for obtainingperformance data that may be used to define the acoustic andelectric responses of phased-array ultrasonic probes includingcontact (with or without a wedge) and immersion linearphase
4、d-array probes used for ultrasonic nondestructive testingwith central frequencies ranging from 0.5 MHz to 10 MHz.Frequencies outside of this range may use the same methodsbut the testing equipment may vary.1.3 When ultrasonic values dependent on material are speci-fied in this document, they are bas
5、ed on carbon steel with anultrasonic wave propagation speed of 5920 m/s (650 m/s) forlongitudinal wave modes and 3255 m/s (630 m/s) for trans-verse or shear wave modes.1.4 This document describes the characterization and veri-fication procedures that are to be carried out at the end stage ofthe manu
6、facturing process of phased array probes. This docu-ment does not describe the methods or acceptance criteria usedto verify the performance of the entire phased array ultrasonicinstrument and probe.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses a
7、re for informationonly.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
8、 to use.2. Referenced Documents2.1 ASTM Standards:2E1065 Guide for Evaluating Characteristics of UltrasonicSearch UnitsE1316 Terminology for Nondestructive Examinations3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice, seeTerminology E1316.3.1.2 Technical Specificati
9、on of the Phased Array Probes:3.1.2.1 datasheetdefined as specification. This is thedocument that defines the general geometry and expectedperformance of a specific model or part number.3.1.2.2 certificationdefined as measured performance ofan individual probe. This is the document that reports them
10、easured performance of a specific probe (specific to a serialnumber).3.1.2.3 probe typecontact or immersion.3.1.2.4 probe shape and sizeprobe form and dimensions.3.1.3 Terminology for Array Probes:3.1.3.1 active aperturepitch times the number of ele-ments.3.1.3.2 cross-couplingalso called “cross-tal
11、k.” An unde-sirable condition where array elements are activated, electri-cally or acoustically, by adjacent elements.3.1.3.3 element widthin a rectangular element, the acous-tic elements short dimension.3.1.3.4 element lengthin a rectangular element, the acous-tic elements long dimension. See passi
12、ve aperture (also calledelement elevation) and Fig. 2.3.1.3.5 element pitch (or pitch)the distance between thecenters of two adjacent array elements.1This practice/guide is under the jurisdiction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.06 o
13、nUltrasonic Method.Current edition approved Nov. 1, 2012. Published December 2012. DOI:10.1520/E2904-12.2For 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 standard
14、s Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.3.6 passive aperturethe dimension of an array el-ements length.3.1.3.7 saw cutalso called “kerf,” space or gap. The spacebetween adjacent e
15、lements.3.1.3.8 virtual probea group of individual array elements,pulsed simultaneously or at phasing intervals to generate alarger acoustic aperture.4. Summary of Practice4.1 The physical, acoustic and electrical characteristicswhich can be described from the data obtained by proceduresoutlined in
16、this guide are described as follows.4.2 Physical AspectsIdentification and physical dimen-sion aspects of the probe should be noted. Details to be notedare described in 7.1.4.3 Center Frequency, Bandwidth And Time ResponseSection 7.2 describes procedures for determining centerfrequency, bandwidth an
17、d time response of the individualelements of the linear array probe.4.4 Sensitivity Range Of ElementsSection 7.3 describes aprocedure to determine variation of sensitivity from oneelement to the next based on a fixed input voltage.4.5 Probe SensitivityThe overall sensitivity performanceof all the el
18、ements in the array is assessed in the proceduredescribed in 7.4.4.6 Element CrosstalkA procedure for assessment ofdamping between elements to eliminate crosstalk is provided in7.5.FIG. 1 Schematic Showing Digitization RateE2904 1225. Significance and Use5.1 This standard practice is intended to pro
19、vide standard-ized procedures for evaluating linear phased-array ultrasonicprobes. It is not intended to define performance and acceptancecriteria, but rather to provide data from which such criteria maybe established.FIG. 2 Two-Channel Schematic Showing Measurement Technique for CrosstalkLegend:A =
20、 active aperture (number of active elements x element pitch)H = passive aperturee = element widthp = element pitchg = saw cut between elements (also called kerf or gap)FIG. 3 Schematic of Key Parameters for Linear ArraysE2904 1235.2 Implementation may require more detailed proceduralinstructions in
21、a format of the using facility.5.3 The measurement data obtained may be employed byusers of this guide to specify, describe, or provide performancecriteria for procurement and quality assurance, or serviceevaluation of the operating characteristics of linear phased-array ultrasonic probes. All or po
22、rtions of the standard practicemay be used as determined by the user.5.4 The measurements are made primarily under pulse-echoconditions. To determine the relative performance of a probeelement as either a transmitter or a receiver may requireadditional tests.5.5 While these procedures relate to many
23、 of the significantparameters, others that may be important 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.5.6 Care must be taken to ensure that comparable meas
24、ure-ments are made and that users of the standard practice followsimilar procedures. The conditions specified or selected (ifoptional) may affect the test results and lead to apparentdifferences.5.7 Interpretation of some test results, such as the shape ofthe frequency response curve, may be subject
25、ive. Small irregu-larities may be significant. Interpretation of the test results isbeyond the scope of this standard practice.5.8 Certain results obtained using the procedures outlinedmay differ from measurements made with phased-array ultra-sonic test instruments. These differences may be attribut
26、ed todifferences in the nature of the experiment or the electricalcharacteristics of the instrumentation.5.9 The pulse generator used to obtain the frequency re-sponse and time response of the probe must have a rise time,duration, and spectral content sufficient to excite the probe overits full band
27、width, otherwise time distortion and erroneousresults may result.6. Instrumentation6.1 Electronic Instruments:6.1.1 The type of instrument(s) used for the tests specified inSection 7 shall be the same as that indicated on the Certifica-tion report and Table 2. They shall also be compliant with theap
28、plicable verification standard for the inspection unit.6.1.2 The following equipment is required in order toevaluate the probes in compliance with this standard:6.1.2.1 A pulser/receiver with a minimum bandwidth of 20MHz, digitizing to 100 MHz, or better, or an oscilloscope (orequivalent) with a min
29、imum bandwidth of 100 MHz.6.1.2.2 Digitizing should be able to get 10 samples inmaximum slope of waveform, as illustrated in Fig. 1.6.1.2.3 A frequency spectrum analyzer with a minimumbandwidth of 100 MHz or a digital oscilloscope/convertercapable of performing fast Fourier transforms (FFT), and/orw
30、aveform capture and digital analysis.6.1.2.4 A phased array instrument may be used with aminimum bandwidth of 20 MHz.6.1.2.5 An impedance analyzer.6.1.2.6 A waveform generator with burst-mode capabilityfor a sine wave at the nominal frequency of the probe.6.1.3 The following additional equipment is
31、optional:6.1.3.1 A hydrophone with an active diameter two timessmaller than the central ultrasonic wavelength of the probebeing tested, but no less than 0.5 mm.TABLE 1 List of Variables for Probe Manufacture and TestingInformation NeededInformation Type(C,I,M)AOptional orRequiredObservationsName of
32、Manufacturer I RequiredProbe type I RequiredInstruments and settings used in the test process I Required See Table 2Test conditions I Required Coupling medium, sound path, target, fixturingSee Table 2Probe Dimensions or shape M or I Optional Casing dimensionsElement shape and size (active and passiv
33、eapertures)I Optional Arrangement of the array(s)Dimensions and geometry of the array(s)Relative position of array in housing I Optional Location of first or last element in relation to thehousingPitch, gap between elements, element width,length and dimensionsI Required Pitch, gap between elements (
34、saw cut), andelement dimensions (length and width)Connector type I RequiredDimensions and material of integrated wedge I Optional Applicable to contact probesDimensions and geometry of integrated wedge(s)Wiring I Optional Cable length and external diameterCenter frequency, bandwidth, and time respon
35、se M RequiredRelative Sensitivity Range of the Elements M or C in dB Required Basic voltage indication of each elementProbe sensitivity M RequiredElectrical Impedance M, I OptionalProbe crosstalk I or C in dB Optional Must state medium if crosstalk reportedALegend:C = CalculationsI = InformationM =
36、MeasurementE2904 1246.2 Test Blocks and Other Equipment:6.2.1 For Contact Arrays with Integral Wedges:6.2.1.1 Blocks made of the same material as the wedge(acrylic, polystyrene, etc.) in shapes complementary to thewedge, allowing sound paths to be equalized.6.2.2 For Contact Arrays (Replaceable Wedg
37、e or DirectContact):6.2.2.1 Blocks with parallel surfaces made of the materialspecified in the datasheet.6.2.3 Immersion Testing for Immersion Arrays:6.2.3.1 A large, flat reflective target. The lateral dimensionof the target shall be large enough that spurious echoes do notinterfere with the return
38、 signal. The thickness of the block shallbe equal to at least five times the wavelength of the probe beingtested, calculated based on the sound velocity in the targetmaterial.6.2.3.2 The water temperature in the immersion tank shouldbe maintained at room temperature during characterization ofthe imm
39、ersion probes in conjunction with the instrument(s).7. Procedures7.1 Physical Aspects:7.1.1 MethodPerform a visual inspection of the probe.7.1.1.1 Confirm that an identification marking is providedon the probe housing.7.1.1.2 Assess dimensional characteristics as required.7.1.1.3 Assess sealed edges
40、 as required.7.1.1.4 Assess electrical connections as required.7.1.1.5 Assess integral wedge surfaces as required.7.1.2 Acceptance CriteriaMake sure the probe is properlyidentified and assembled and that there are no signs of physicaldeterioration, which could reduce the reliability of the probe.For
41、 in-service applications, either compare calibration resultsagainst the initial standard, or send probe back to manufacturerfor re-certification.7.2 Center Frequency, Bandwidth and Time Response(Waveform Duration)See Annex A1, Annex A2 and AnnexA4 in ASTM E1065 for guidelines.7.2.1 Measurements shal
42、l be taken on each element of theprobe.7.2.2 For immersion probes, the target is placed at a waterpath as referenced in section 6.2, typically at the natural focus,in accordance to the datasheet. Measurements shall be takenunder normal incidence on any one of the detectable returnechoes from the tes
43、t block.7.2.3 For contact probes, the measurement shall be taken viadirect contact (water or gel couplant) on the test block definedin section 6.2.7.2.4 The transmitter pulse should be a shock excitationhaving a duration of one-half cycle of the nominal probefrequency.7.2.5 Acceptance CriteriaThe va
44、lues obtained for thefrequency, bandwidth, and time response are the suggestedvalues of each element.7.2.6 Exceptions for tolerance can be based on extenuatingcircumstance, like cable length, element impedance.7.2.7 Center Frequency (Fc):7.2.7.1 Average of all elements must be within 610%ofthe centr
45、al value specified.7.2.7.2 Range of center frequency for all elements must bewithin 610 % of the center frequency average for all of theelements.Fcavg= 10 % of the nominal frequency of the probeFcmin 0.9 * FcavgFcmax 1.1 * Fcavg7.2.8 Relative Bandwidth (BW):7.2.8.1 Average of all elements must be a
46、value specifiedby the manufacturer. If appropriate, further agreement on thespecifications can be made with the client.7.2.9 Time Response (Waveform Duration):7.2.9.1 Time Response (waveform duration) may be speci-fied at a variety of amplitude values below the maximum.Typically these values are 20
47、dB and 40 dB, measured perASTM E1065.7.2.9.2 Average of all elements must be a value specifiedby the manufacturer. If appropriate, further agreement on thespecifications can be made with the client.7.2.9.3 Average Time Response value specified by manu-facturer. If appropriate, further agreement on t
48、he specificationscan be made with the client.7.3 Relative Sensitivity Range of the Elements within aProbe in Pulse-Echo Mode:7.3.1 Measurements shall be taken in the same conditions asthe center frequency, bandwidth, and pulse duration measure-ments.7.3.2 In the case of probes with integrated wedges
49、, themeasurement will be taken on the complementary test blockdefined in section 6.2, which will enable each of the elementsto be placed in conditions identical to the ultrasonic path.7.3.3 The reference echo amplitude of each element ismeasured (in volts). The sensitivity of each element is calcu-lated in dB based on the following formula:Sensitivity of an element = 20 log (Velement/Vexcitation)7.3.3.1 Sensitivity variation (gain deviation) for an array =Maximum sensitivity of an element minus minimum sensitiv-ity of an element within an array.TABLE
