Ssc-330 Practical Guide for Shipboard Vibration
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SSC-330 PRACTICAL GUIDE FOR SHIPBOARD VIBRATION CONTROL AND ATTENUATION Thisckxumenthasken approved forpublicreleaseaudsalqits distributionismt~ SHIP STRUCTURE COMMITTEE 1990 6EIF STRUCTUN2 ~ITTES TEE GRIP STRU~ mITTEE is mnatituted to prosecute a research program to improw the bull mtructurem of sups ●d otlnsr ●arhs mtructureaby ●n ●xtendon of kmwledge prtainlng to demign, materials and mettds of conet ruction. RAM C. 7. Lusk, Jr., DSCG (~aiman) Mr. T. W. -08S Chpa;:t$f f ice of Us rcbant Uarine Aeswiatc Msiniztrator for Shipbuilding, @erationa & U. S. ~ast Qmrd madqmrtern Research Maritime Ad=inimtration Hr. P. M. Palemo Mr. S. B. G<egory Executim Director ~ief, Technology AsacsMent Ship -sign & Integration & Research Branch Directorate Mir82rals Management Semite Naval Sea Sy8teu ~nd Mr. W. k ~nnan Hr. T. W. Allen Vice president Engineering Officer American Bureau of shippi~ Military Sealift ~mmaml COR D. B. Aderwn, U. S. mast ma rd (Secrets ry) SHIP STRUCTURZsuBcoNNImEE The SHIP STRUCTUMSUBC_ITTEE acts for the Ship Structure ~mmittee on technical matters by providi~ technical c-rdirmtion for the determi~tion of goals ad objectives of the prcgram, and by ●valuating and interpreting the results in terns of structural design, construction ard qeration. D. S. COASTGUARD MILITARY SEALIFT CWfKAND CA3T A. E. HEWN N& D. STEIN ~T J. R. WALLACE HR. T. W. CEAR4AN NR. J. S. SPENCER HR. A. ATTERMEYER NR. R. E. WILLIAM MR. A. B. STAVWY NAVALS= SYSTR4S CWMAND mRIcm BUREAtIOF SHIPPING NR. J. B. O’BRIEN (~IRMAN) DR. D. -IJU cDR R. BUBECK NR. I. L. STERN KR. J. E. GAGORIK NR. B. NADALIN MR. A. E. ENGLE NR. S. G. ARNTSON (COTR) HINERM5MANAGEMENTSERVICE HR. G. W~DS (COTR) NR. R. GIANGEKELLI MR. R. C. E. SMITH MAXITIWEAIXINIST~TION INTERNATIOW smP STRUCTURES CONGRESS NR. F. SEIBOLD NR. S. G. STIANSEN- LIAISON WR. N. O. BAMW.ER DR. W. M. NACL.EhN AMERICANIRON t STEEL INSTITUTE WR. n. w. Tomk HR. J. J. SCEWIDT - LIALSON NATIOWAL KADEfY OF SCImCES CCHMITTEEOWMARINE6TR~ M. A. DUDLEY HAPF - LIAISON STATE DIVERSITY OF NY MARITIMECOLLEGE MR. R. W. RtmKE - LIAISON DR. W. R. WRTER - LIAISON * Suxmy OF WAVAL ARcEIzm & U.S. ~AST GUARDA~Y NARINE =IN’EERS LT J. -LE - LIAISON KS. M. 0. BAMIER - LIAISON nil. r. SELLARS - LLAISON U. 8. MAVALACADR$Y WELDIWG RISEkRCB ~lL DR. R. BEATTACMRYYA- LIAISON DELG. W. OYLER- LIAISCM U.S. MERC~ KARINEACAD= . DR. C. B. KIN - LIAISON m Cn n I 0 ,.-.!.h,,> i,:,.,,,; .“.. ,, ., ‘“’) ,’, L9 w 0 MemberAgencies: AddressCorrespondence-to: United States Coast Guard & Secretary,ShipStructureCommittee Naval Sea Systems Command U.S.CoastGuardHeadquarters,(G-MflP13) Maritime Administration Washington,D.C,20593 American Bureau of Shipping ship (202)426-2197 Military Sea/ift Command structure Minerals Management Service Committee An Interagency Advisory Committee Dedicated to the Improvement of Marine Structures SR-1293 Although ship designers make every effort to prevent objectionable and detrimental vibrations before a vessel is constructed, there are times when vibrations are at an unacceptable level after construction or major modification. This volume is intended to aid shipboard personnel in locating the source of unacceptable vibrations and to guide them in curing their own problem. A chapter giving typical examples is included for this purpose. With this guide in hand, shipboard personnel will be better able to know when they need to call on expert assistance should the need arise. For shipboard personnel who wish to know more about vibration theory, an appendix is included. CLYDE Rear Admira Chairman, Ship Structure Committee ,.+-.... .. ----- . .... ...”.--------.... .....-,,.,,_.,._..__.<, .................. ----- . ? J*chnical k~ort hcumcntutiofi Pn~e 7 1. Roped w.. 2. Go.mrmmsnr A.cm..i*n N=. hcipioml’s ca*dOgNO. SSC”330 4. lid, -d Sub~,?10 S. Rgpori Dot* Practical Guide for Shipboard Vibration Control March 1984 and Attenuation 6. POrfOnmmQ or~mn,;mt,On Cda SHIP STRUCTURE COMMITTEE 8. P.rformina Or~~itotion Roptt ND. 7. AwAm#,) E.F. Noonan, G.P. Antonides, and W.A. Wood SR-1293 9. P*tfmrm,ngOrgm,zottmfiHmm -4 Addtmss 10. WorkUn,tNo. (TRAIS) NKF Engineering Associates, Inc. 8150 Leesburg Pikg, Suite 700 11.C.w,.m● GromI No. Vienna, Virginia 22180 DTCG 23-83-C-20031 13. Tvpool R~or*wd Por~odGr.md 1 12. &msorq A9mnE7 N-c rnd Add?asb U.S. Department of Transportation FINAL United States Coast Guard Office of Merchant Marine Safety )4. +nc.r,ng A,oncybd. Washington, D.C. 20593 I Is,~l~tsryNotc$ Sponsor – Ship Structure Committee Washington, D.C. 16. Ab*rroct A practical guide has been developed to provide operators, shipyards, ship– owners, and others who must deal with ship vibration problems, but who have limited knowledge and experience in the field, with an understanding of the nature of the most common problems frequently encountered, how to assess and evaluate them, and what alternatives are available for corrective action. A review of vibration fundamentals and a detailed explanation of the nature and scope of shipboard vibration are presented to assist in the understanding of the various problems typically encountered. Available instrumentation and the proper method of their use in shipboard studies is presented along with recommended vibration criteria and an approach to their use in problem solving. Examples of typical problems and their solutions are inc:uded. 4 Shipboard Vibration Document is available tothe public through Vibration of Ship’s Hull and Machinery the National Technical Information Vibration Criteria for Shipboard Use Service, Springfield, Virginia 22161 8 1 1?. krity~lonsif. (ofhis~t) ~. &srity Clms*if. (*f thigp~*) 21.Ho.dPo#*s ~ Pfic* UNCLASSIFIED UNCLASSIFIED 201 F9~W1F;700.7 m-72) R*dJcthtmfQlod ~ow#tlwlMd ,,, ,.. ..—-., ....,,- ., —----- . .. .... .. .... ... .--__,. ‘.!.-Ad’ .-. —..—. .._ . ..- --- . ..— . S2 Zz lZ 02 61 81 M m st ?1 H 21 It Ot 6 g L y s * E ~ I !43 I I 1111111111111111111111111111111111111111111111111111111111111[111111111111111111Ill!1111illill]1111Ill!11111111111111111111f[ll1111111111111Ill!Ill1111111111[1111111111111111][11111111 Ilati9**I.Belllll 1111#1110181#l,, Ill, 11,, ,,, ,,, ,,, ,,, ,,, ,,, ,,, ,,, ,,, , ,,, , Ip Ip Ip IIp Ip Ip IIIp Ip Ip Ill Ip I I Ip Ip I I 1[1 Ip Ip Y 8 7 c B ,P13la’1 1 inMOs iv PRFFACE The purpose of this Guide is to provide operators, shi yards, ship owners, and others who must deal with ship vibration problems, but wRo have lim- ited knowiedge and experience in the field, with an understanding of the nature of the most common probiems frequently encountered, how to assess and evaluate them, and what alternatives are available for corrective action. Basic informa- tion on vibration fundamentals, instrumentation, measurement pr-edures, and vibration criteria is included. Typ ica I examples of shipboard vibration prob- iems encountered and their solutions are also presented. TABLE OF CQNTENTS SKLi.sm 1.0 lNTRODU~ION 1-1 2.0 SCOPE AND FIELD OF APPLICATION 2-1 3.0 lNTRODUCil ON TO SHIP VIBRATION - EXCITATION AND RESPONSE 3-1 3.1 Background 3-1 3.2 Hull Girder Vibration 3-2 3.2.1 Hull Girder Excitation 3“3 3.2.1.1 Shaft Frequency Forces 3“3 3.2.1.2 Propeller Forces 3-4 . 3.2.1 .2.1 Bearing Forces 3-5 3.2.1 .2.2 Hull Pressure Forces 3-5 3.2.1 .2.3 Effect of Propeller Forces 3-5 3.2.2 Hull Girder Response 3-7 3.2.2.1 Modes of Vibration of the Hull Girder 3-7 3.2.2.2 Frequency of Vibration of theliull Girder 3-7 3.2.2.3 Effects of Adverse Operat ng Conditions 3-12 3.2.2.3.1 Sea Conditions 3-12 3.2.2.3.2 Hard Maneuvers 3-12 3.2.2.3.3 Shaliow Water 3-12 3.2.2.3.4 Light Draft Condition 3-12 3.3 Vibration of Major Substructures 3-13 3.3.1 Response of MaJor Substructures 3-13 3.4 Vibration of Locai Structural Elements 3-14 3.5 Vibration of Shipboard Equipment 3-15 3.5.1 Passive Shipboard Equipment 3-15 3.5.2 Active Shipboard Equipment 3-15 3.6 Vibration of Main Propulsion Machinery 3-16 3.6.1 Dynamic Unbalance and Misalignment 3-16 3.6.2 Dynamic Shaft Stresses 3-17 3.6.3 Longitudinal Vibration 3-17 ii TABLE OF CX3NTENTS (Continued) 3.6.4 Torsional Vibration 3-18 3.6.5 Lateral Vibration 3-19 3.7 References 3-20 4*O MEASUREMENT MElHODS 4-1 4.1 Instrumentation 4-1 4.1.1 Mechanical Instruments 4-1 4.1.1.1 Reeds 4-1 4.1.1.2 Askanla 4-2 4.1.2 Transducers 4-2 4.1.2.1 Accelerometers 4-2 4.1.2.2 Velocity Gages 4-3 4.1.2.3 Displacement Gages 4-3 4.1.2.4 Strain Gages 4-3 4.1.3 Signal Conditioners 4-4 4.1.3.1 Differential Amplifiers 4-4 4.1.3.2 Charge Amplifiers 4“4 4.1.3.3 Strain Gage Amplifiers 4-5 4.1.3.4 Filters 4-5 4.1.4 Recorders 4-5 4.1.4.1 Meters 4-6 4.1.4.2 Osciiioscopes 4-6 4.1.4.3 Oscii lographs 4-7 4.1.4.4 Tape Recorders 4-7 4.2 Quantities to be Measured 4-8 4.2.1 Displacement, Velocity, or Acceleration 4-8 4.2.2 Frequency Range 4-9 4.2.3 Time History or Frequency Spectra 4-9 4.3 Analysts and Reporting of Data 4-9 4.3.1 Manuai Method 4-1o 4.3.2 Envelope Method 4-12 4.3.3 Spectral Method 4-17 iii \-,-.. TABLE OF ~NTENTS (Continued) tlon Pay 4.3.4 Hlstcgrams of Instantaneous Values 4-20 4.3.5 Histograms of Peak Values 4-22 4.3.6 Reporting Formats 4-22 4.4 Transducer L~atlons 4-24 4.4.1 Hull Stern 4-25 4.4.2 Thrust Bearing 4-25 4*4.3 Main Propulsion System, Longitudinal 4-26 4.4.4 Deckhouse 4-27 4.4.5 Hull Girder 4-27 4.4.6 Rotating Machinery 4-27 4.4.7 Resonant Equipment 4-28 4.4.8 Torsional Vibration 4-28 4.4.9 Main Propulsion Syslwn, Lateral 4-29 4.4.10 Local Structures 4-29 4.5 Test Conditions 4-29 4.6 Test Prwedures 4-30 4.6.1 Calibration Procedures 4-30 4.6.1.1 Accelerometers 4-30 4.6.1.2 Velocity Gages 4-31 4.6.1,3 Proximity Probes 4-31 4.6.1.4