1、Designation:F217402(Reapproved 2015)Standard Practice forVerifying Acoustic Emission Sensor Response1This standard is issued under the fixed designation F2174;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 practice is used for routinely checking the sensi-tivity of acoustic emission(AE)sensors.It is intended toprovide a reliable,precise
3、ly specified way of comparing a setof sensors or telling whether an individual sensors sensitivityhas degraded during its service life,or both.1.2 The procedure in this practice is not a“calibration”anddoes not give frequency-response information.1.3 The values stated in SI units are to be regarded
4、as thestandard.The values given in parentheses are for informationonly.1.4 This practice does not purport to recommend one sensormanufacturer over another nor does it imply that one type ofsensor will react differently from another when using thisprocedure.1.5 This standard does not purport to addre
5、ss 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.Referenced Documents2.1 ASTM Standards:2E650 Guide for Moun
6、ting Piezoelectric Acoustic EmissionSensorsE750 Practice for Characterizing Acoustic Emission Instru-mentationE976 Guide for Determining the Reproducibility ofAcousticEmission Sensor Response3.Significance and Use3.1 Degradation in sensor performance can occur due todropping,mechanical shock while m
7、ounted on the teststructure,temperature cycles,and so forth.It is necessary anddesirable to have a simple measurement procedure that willcheck the consistency of sensor response,while holding allother variables constant.3.2 While test blocks of many different kinds have beenused for this purpose for
8、 many years,an acrylic polymer rodoffers the best all-around combination of suitable acousticproperties,practical convenience,ease of procurement,andlow cost.3.3 Because the acoustic properties of the acrylic rod areknown to depend on temperature,this practice requires that therod,sensors,and coupla
9、nt be stabilized at the same workingtemperature,prior to application of the practice.3.4 Attention should be paid to storage conditions for theacrylic polymer rod.For example,it should not be left in afreezing or hot environment overnight,unless it is given timefor temperature stabilization before u
10、se.3.5 Properly applied and with proper record keeping,thispractice can be used in many ways,such as:3.5.1 To determine when a sensor is no longer suitable foruse.3.5.2 To check sensors that have been exposed to high-riskconditions such as dropping,overheating,and so forth.3.5.3 To get an early warn
11、ing of sensor degradation overtime.3.5.4 To obtain matched sets of sensors and preamplifiers.3.5.5 To verify sensors quickly but accurately in the field,and to assist troubleshooting when a channel does not pass aperformance check.4.Apparatus4.1 Acrylic Polymer Cylindrical Rod(Fig.1)should beused.Th
12、e actual material of the acrylic polymer rod ispoly(methylmethacrylate)(PMMA).4.1.1 Dimensions of the rod should be 78.74 cm(31 in.)long by 3.81 cm(1.5 in.)in diameter with ends cut true andsmooth with a surface finish of 0.4 m rms(0.16 in.).4.1.2 Other lengths of rod are acceptable,provided thatthe
13、re is sufficient distance to attenuate and prevent reflectedsignals from the non-sensor end of the rod reaching the sensor.4.1.3 A permanent reference mark(for example,an“X”)isplaced on the rod at a distance of 10.16 cm(4 in.)from oneend;this marks the spot where the lead is to be broken.It is1This
14、practice is under the jurisdiction of ASTM Committee F18 on ElectricalProtective Equipment for Workers and is the direct responsibility of SubcommitteeF18.55 on Inspection and Non-Destructive Test Methods for Aerial Devices.Current edition approved April 1,2015.Published May 2015.Originallyapproved
15、in 2002.Last previous edition approved in 2008 as F2174-02(2008).DOI:10.1520/F2174-02R15.2For 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 standards Document Summary p
16、age onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 convenient to provide a very small spotface,for example,0.796 0.05-mm(0.031 6 0.002-in.)diameter and 0.076 to 0.178mm(0.003 to 0.007 in.)deep at this reference mark point,torest the tip of the pencil lead to avoid slippage during the leadbreak process.4.2 Hsu-Nielsen Pencil Lead Break Source,0.3 or 0.5 mm.A Nielsen shoe as described in Guide E976 is optional.4.3 Se
