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1 DTIcDavid Taylor Research Center00 Bethesda, Maryland 20084-5000YE-0 NDTRC/PAS-89-28 October 1989 Propulsion and Auxiliary Systems DepartmentIResearch and Development ReportUSER'S SUPLa TO MIL-STD-740-2 MODIFIED FOR MEASURTMENS TO 20 KHZbyD. MaxwellR. W. Miller0-JC NApproved for public release; distribution isEn DTIC= 10 ELECTE;"-Go 0 011990!.. ,B L)I I& ? .ff lIPMAJOR U T IOMPONENTCODE 011 DIRECTOR OF TECHNOLOGY, PLANS AND ASSESSMENT12 SHIP SYSTEMS INTEGRATION DEPARTMENT14 SHIP ELECTROMAGNETIC SIGNATURES DEPARTMENT15 SHIP HYDROMECHANICS DEPARTMENT16 AVIATION DEPARTMENT17 SHIP STRUCTURES AND PROTECTION DEPARTMENT18 COMPUTATION, MATHEMATICS & LOGISTICS DEPARTMENT19 SHIP ACOUSTICS DEPARTMENT27 PROPULSION AND AUXILIARY SYSTEMS DEPARTMENT28 SHIP MATERIALS ENGINEERING DEPARTMENTDTRC ISSUES THREE TYPES OF REPORTS:1.

2 DTRC reports, a formal series, contain information of permanent technical carry a consecutive numerical identification regardless of their classification or theoriginating Departmental reports, a semiformal series, contain information of a preliminary,temporary, or proprietary nature or of limited interest or significance. They carry adepartmental alphanumerical Technical memoranda, an informal series, contain technical documentation oflimited use and interest. They are primarily working papers intended for internal use. Theycarry an identifying number which indicates their type and the numerical code of theoriginating department. Any distribution outside DTRC must be approved by the head ofthe originating department on a case-by-case S402151 (Ae.)

3 2-8S)UNCLASSIFIEDSECURITY CLASSIFICATION OF THIS PAGEREPORT DOCUMENTATION PAGEla. REPORT SECURITY CLASSIFICATION lb RESTRICTIVE MARKINGSU nclassified2a. SECURITY CLASSIFICATION AUTHORITY 3 DISTRIBUTION/AVAILABILITY OF REPORT, Approved for public release;2b. DECLASSIFICATION i DOWNGRADING SCHEDULE distribution unlimited4 PERFORMING ORGANIZATION REPORT NUMBER(S) 5 MONITORING ORGANIZATION REPORT NuMBER(S)PAS-89-286a NAME OF PERFORMING ORGANIZATION 6D OFFICE SYMBOL 7a NAME OF MONITORING ORGANIZATION(if applicable)David Taylor Research Center Code 27446c. ADDRESS (City, State, and ZIP Code) 7b ADDRESS (City. State, and ZIP Code)Bethesda, MD 20084-5000Ba. NAME O FUNDING i SPONSORING 8b OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBERORGANIZATION (if applicable)Naval Sea Systems Command SEA55 NBc.

4 ADDRESS (City, State, and ZIP Code) 10 SOURCE CF FUNDING 20362-5101 PROGRAM PROJECT TASK WORK UNITW ashington, ELEMENT NO. NO NO ACCESSION NO11 TITLE (include Securitv Classification)User's Supplement to MIL-STD-740-2 Modified for Measurements to 20 KHz12 PERSONAL AUTHOR(S)Maxwell, D.; Miller, R. TYPE OF REPORT 13b TIME COVERED 14. DATE OF REPORT (Year, Month, Day) I1S PAGE COUNTF inal FROM _ TO_____ 1989, October 4216 SUPPLEMENTARY NOTATION17 COSATI CODES 18 SUBJECT TERMS (Continue on reverse if necessary and identify by block number)FIELD GROUP SUB-GROUP19 ABSTRACT (Continue on reverse if necessary and identify by block number)This supplement to MIL-STD-740-2 is specifically diected to provide guidance forperforming structureborne vibratory acceleration measurements to 20 KHz.

5 Hissupplement modifies the standard in those areas where changes are necessary tomake high frequency measurements. This supplement also provides guidance inthose areas where past experience has shown that many naval shipboard equipmentmanufacturers have had difficulty in interpreting the requirements of the DISTRIBUTION tAVAILABILITY OF ABSTRACT 21 A8rTRA(T SECURITY CLASSIFICATION['1 UNCLASSIFIEDIUNLIMITED M SAME AS RPT El DTIC USERS22a NAME O1 RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Include Area Code) 2c OFFICE SYMBOLM axwell, D. (301) 267-4889 Code 2744DD FORM 1473, 84 MAR 83 APR edition may be used until exhausted SECURITY CLASSIFICATION OF THIS PAGEAll Other editions are obsolete * o ..4 , m O.)]

6 35 goi .. 1 INTRODUCTION .. 1 APPROACH .. 1 VENDORS PROPOSED EQUIPMENT EVALUATION PLAN .. 2 MEASUREMENT-POINT LOCATION .. 2 ACCELEROMETER ATTACHMENT .. 3 Preparation .. 3 Attachment .. 3 Surface Preparation for Cementing .. 4 INSTRUMENTATION .. 5 Accelerometer Characteristics .. 6 Preamplifiers .. 7 Voltage Preamplifiers .. 8 Charge Preamplifiers .. 8 Integral Amplifiers/Line Drivers .. 9 Remaining Instrumentation .. 9 CALIBRATION OF INSTRUMENTATION .. 10 MEASUREMENT PROCEDURES .. 11 REPORTING STANDARDS .. 13 DETAILED REPORT TO BE SUBMITTED AFTER E-'-' ATION .. 13 ADDITIONAL READING .. 14 FIGURES1. Curve; E. ample structureborne acceptance criteria 152. Drawing; Example of a motor-driven unit.

7 163. Drawi.:,, Triaxial assembly of accelerometers ..17i--'""'"- mmmnnmu n umn~ |m m~m| IFIGURES (Continued)4. Drawing; Example of measurement-point locationson a flanged unit .. 185. Drawing; Vaneaxial fan measurement-poin, locations 196. Drawing; Motor driven pump measurement-pointlocations .. 207. Drawina: Motor driven compressor measurement-pointlocations .. 218. Drawing; Surface preparation .. 229. Drawing; Preferred method of accelerometer attachment 2310. Drawing; Anodized aluminum stud used to electricallyisolate the accelerometer from the machinery part ..2411. Drawing; Stainless stecl insulated stud used toelectrically isolate the accelerometer from themachinery part ..2512. Drawing; Anodized aluminum cementing stud used toelectrically isolate the accelerometer from themachinery part.

8 2613. Block diagram; Vibration measurement system .. 2714. Curve; Accelerometer-preamplifier noise level .. 2815. Diagram; Comparison calibration of accelerometers 2916. Diagram; Electrical calibration .. 3017. Diagram; Laboratory electrical calibration ..3118. Didgram; Laboratory electrical calibration ..3219. Diagram; Mechanical field calibration ..3320. Example of plotting format for graphs 1/3-octave-band analysis .. 34 TABLE 11. Acceptable cements ..i il 1 1 I II I I I I I DIABSTRACTThis supplement to MIL-STD-740-2 isspecifically directed to provide guidance forperforming structureborne vibratoryacceleration measurements to 20 KHz. Thissupplement modifies the standard in thoseareas where changes are necessary to make highfrequency measurements.

9 This supplement alsoprovides guidance in those areas where pastexperience has shown that many naval shipboardequipment manufacturers have had difficulty ininterpreting the requirements of the standard.,"/'INTRODUCTIONMIL-STD-740-2 specifies acceptable instrumentation andprocedures for the measurement and analysis of structurebornevibratory acceleration generated by naval shipboard equipment. Thestandard also specifies acceptance criteria for structurebornevibratory acceleration levels; however, equipment purchasespecifications may include criteria which supersede those definedin MIL-STD-740-2. The referenced documents listed in the standardalso describe acceptable instrumentation and measurementprocedures.

10 This supplement discusses some of the requirementsgiven in MIL-STD-740-2 and is intended to provide further guidancefor performing structureborne noise evaluation of naval shipboardequipment. The equipment purchase specification should provide theappropriate implementation guidance in accordance with of supplement is also intended to provide further guidancefor performing structureborne noise evaluation over an extendedfrequency range. In particular, the ability to extend reliablemeasurements from 10 KHZ to 20 KHz is addressed. The items thatsignificantly affect the ability to achieve these measurements arethe accelerometer, preamplifier, and the method of basic method used to determine equipment acceptance isthe measurement of the structureborne vibratory acceleration level(L,) in decibels (dB) at specific locations on the otherwise specified, equipment is considered to have--acceptable structureborne vibratory acceleration levels when none,of the levels measured at the designated locations exceed theapplicable structureborne acceptance criteria specified in theprocurement package.