ASTM_E_2075_-_E_2075M_-_15.pdf

Designation:E2075/E2075M15Standard Practice forVerifying the Consistency of AE-Sensor Response Using anAcrylic Rod1This standard is issued under the fixed designation E2075/E2075M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last 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 is used for routinely checking the sensi-tivity of acoustic emission(AE)sensors.It is intended toprovide a reliable,precisely specified way of comparing a setof sensors,or telling whether an individual sensors sensitivityhas degraded during its service life,or both.1.2 This practice is not a“calibration”nor does it givefrequency response information.1.3 UnitsThe values stated in 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 standard.1.4 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.Referenced Documents2.1 ASTM Standards:2E650 Guide for Mounting Piezoelectric Acoustic EmissionSensorsE750 Practice for Characterizing Acoustic Emission Instru-mentationE976 Guide for Determining the Reproducibility ofAcousticEmission Sensor ResponseE2374 Guide for Acoustic Emission System PerformanceVerification3.Significance and Use3.1 Degradation in sensor performance can occur due todropping,mechanical shock while mounted 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 many years,an acrylic polymer rodoffers the best all-around combination of suitable acousticproperties,practical convenience,ease of procurement and lowcost.3.3 Because the acoustic properties of the acrylic rod areknown to depend on temperature,this practice requires that therod,sensors,and couplant be stabilized at the same workingtemperature,prior to verifying the sensors.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 use.3.5 Properly applied and with proper record keeping,thispractice can be used in many ways.The user organization mustdetermine the context for its use,the acceptance standards andthe actions to be taken based on the lead break results.Thefollowing uses are suggested: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 warning of sensor degradation overtime.This can lead to identifying conditions of use,which aredamaging sensors,and thus,to better equipment care and lowerreplacement costs.3.5.4 To obtain matched sets of sensors,preamplifiers,instrumentation channels,or a combination thereof,for moreuniform performance of the total system.3.5.5 To save time and money,by eliminating the installa-tion of bad sensors.3.5.6 To verify sensors quickly but consistently in the fieldand to assist trouble-shooting when a channel does not pass aperformance check.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.04 onAcoustic Emission Method.Current edition approved June 1,2015.Published June 2015.Originallyapproved in 2000.Last previous edition approved in 2010 as E2075-10.DOI:10.1520/E2075_E2075M-15.2For 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 page onthe ASTM website.*A Summary 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 States1 3.6 All the above uses are recommended for consideration.The purpose of this practice is not to call out how these uses areto be implemented,but only to state how the test itself is to beperformed so that the results obtained will be accurate andreliable.4.Apparatus4.1 Acrylic Polymer Cylindrical Rod(Fig.1),should beused.The actual material of the acrylic polymer rod ispolymethylmethacrylate.34.1.1 The rod shall be cast,not extruded.4.1.2 Dimensions of the rod should be 78.7 cm 31 in.