4 - Memorial University of Newfoundland DAI

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Since the de& sertioo of the structure (because of ils gomelricd m18- figuration) is inherently more floxiblc than Ihc jacket (i.e., the section below the water Iwel), it was considered that the extrn lt~mpcd masses zltoaid Iro distributed in the region where mom flexibility was mquirod. Ilctlcc, tho loeations of the weight holden were relocted at Lhc nodes alotlg Lhc ntnitt columns of the jacket, into whicl, the extra l umd mssses wore iomrted.
Chapter 5 Experiment a1 Study Tixis chapter deals wilh the dynamicd testing of thc experimental modei. Dynamic Icsting is very advsntageous, bezsuae it urn be used to: (i) vcrily the analytical modei, (ii) diagnose (troubie-shoot) the vibration prohiem, (iii) assess design ehanp in the atrueture, and (iv) devise a dynamic modei lor parts of the structure too complicated to model andytiediy. Wr all thoso cases, the objntive of the dynamic testing procedure was to cvcile and identify the modes of vibration of structure and to determine the dynamic responr. In both the andyticd and experiment4 phme of this investigation, the common entity WM the aet of modal parameters. The rcintionsinip is summarized diagrammatically in Figure 5.1. 5.1 Equipment Installation A bricl description of the equipment used in the experiments is presented in tlkis section. First the warn maker system is dncribed, followed by the
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NOTICE The quallty of this microfor
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I*I Et"" :lbL="*"" k.. bpilmsa7d Di
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Acknowledgements I should like lo t
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Abstract As a result of the increas
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Contents List of Figures xii List o
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4.6.3 Fnbrieatiox of tllc Rcduced M
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A Selected Algoilthma 278 A.1 Diago
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4.5 Member Configuration at level #
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7.21 Dynamic Mode # 6 (Intact Model
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7.49 Typical Measured lnput Wnve Sp
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7.66 hulls fmm Accelerometer A2 due
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D.ll DynamicMode # I (Intact Model)
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List of Tables 4.1 Symbols, Units a
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8.9 Pacent Changes in Resonant Frrq
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List of Symbols d(k) .i(k) A A(L1 1
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autosp~trni density of r(t) cms-spe
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0,1,2
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[@I a Pu. P. P:,," P.. o2(k) instan
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een recorded, then it is beneficial
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Associated with every vibration mod
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Such s model is called a dynamicall
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presenlcd. Chapter 3 contains the t
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al frequcncic. occurred when member
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detwM from the data roeorded (later
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y Duggan d a!. [a]. This study inve
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~~lidity of the results war rompsro
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nic~~~aan:immcdiateiyuseful, they a
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tlncayatem hehavior oftrusswork pla
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Chapter 3 Theoretical Modelling Tll
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3.2 Wave Theories Works by earlier
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F;-RY% WAVE THEORY) 1/20 I "w/Lw DE
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DIRECTION OF WAVE PROPAGATION FIG.
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liero, d and ita wlocity component
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and and a+ "=-. OY = wA~inl~IW(1+ s
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FIG.3.4 ARBITRARILY ORIENTED CYLIND
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~i n long c mtd wave is being conai
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inrther. Ultimately, the resulting
Page 80 and 81: equcncia and mode shapes, equalion
Page 82 and 83: Toestablish tho relationship betwee
Page 84 and 85: Furthermore, from equation (3.56),
Page 86 and 87: lG.3.6 SIMULATED 3-D AND STICK MODE
Page 88: 1. priam&tic heam members, 5. sir d
Page 92 and 93: The equation of motion for each ele
Page 94: From tho ~tatic dispiaeemont muita,
Page 97 and 98: instance, the non-dimensional equal
Page 99 and 100: functional relationship relating th
Page 101 and 102: whcre F, 't iinstantanmua force at
Page 103 and 104: Table 4.1 Symbols, Unit. and Dimens
Page 105 and 106: thc Buckinghm r-Thmrem (i.c., I2 te
Page 107 and 108: That is, equations (4.28) and (4.29
Page 109 and 110: C. Ilence, if the dynamic amplifica
Page 111 and 112: where (2) is the general gmmdric or
Page 113 and 114: the prolotype. Damping is dcfincd b
Page 115 and 116: 2 LEVEL # 7 1 28956DO NOTE: ALL DIM
Page 117: Mataial= Structural Steel, E = 206.
Page 122 and 123: LEVEL C6 NOTE: ALL DlMENStONS IN m
Page 124 and 125: Table 4.5 Relevant Materiel Propert
Page 128 and 129: FlG.4.9 COMPLETED STRUCTURE. 89
Page 134 and 135: % FINITE ELEMENT ANALYSIS (COMPUTER
Page 136 and 137: 3 53 I CONTROL RM SECTION A-D. MEZZ
Page 139 and 140: I I SERVO CONTROLLER MODEL 408.1% j
Page 141 and 142: LEGEND FI B F2 FREE VlBllTlDN INITI
Page 144 and 145: 5.1.4 Response Circuit Data acquisi
Page 146 and 147: I ~T.UG~U~E LEGEND: DYIIYT I., 10 A
Page 150 and 151: the basis upon which the irregular
Page 152 and 153: then manipulated by the computer ro
Page 154 and 155: ,.. G STRUCTURE IN STILL WATER STRU
Page 156 and 157: dter every set of hen wave excitati
Page 158 and 159: To gather spectral information fmm
Page 160 and 161: is the timelag between silrnplev~l~
Page 162 and 163: ics, with a lew notable exceptions,
Page 164 and 165: If bath aides of the dove cguntion
Page 166 and 167: Conversely, r(1) can be estimated b
Page 168 and 169: quires ahout N(M + 1) + 9Y1 arithme
Page 170 and 171: So equation (6.18) become: I, i = C
Page 172 and 173: At each resonant frequency, the hdl
Page 176: 6.5 Impact Testing Impact testa wer
Page 179 and 180: Chapter 7 Theoretical and Experimen
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Table 7.1 Natural Wequeney Comparis
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Therefore, with the natural freluen
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Pi7 Be: kD! SF:& iid id . -5 i#@ Ba
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(i.o., at noder 6, 12, 18, 22 and 2
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tirne dntn;lis reprcsez~lnlioti of
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-CUI~IW~~~ anstmr 9~1sn-mmu3n DL um
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the posilivc and nogntivr peaks. Re
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Table 7.7 X-Direction Results From
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2 GEhEnnlEO FRDM TdE WrllTE hOISE l
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FIG. 7.53 MEASURED INPUT WRVE FROM
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'IUnU133dS 3SIR1 31IHI 9NISn--91 30
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Table 7.9 MEM Damping Estimates fro
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7.2.3 Impact Test Results In Chsptc
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(K 01 0 01- OZ- DE- 0,- OBI (KI 09
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Chapter 8 Discussion of Results In
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of rnemhcr removal can he visually
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emoved is a cancellation offecl, an
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Force Variation Along the Jacket. P
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fi~t on the lower rrequency end of
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pond approximately to thasc which c
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'Ikble 8.1 Measured Resonant Rsquen
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Table 8.6 Measured Resonant Wequenc
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After a close look at the measured
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Table 8.11 Percent Changes in Reson
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Table 8.16 Percent Changes in Reson
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apprmiably. Since the tmnsa of the
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'*~+12 \5 \8 h4 h7 $0 FREOUENCY IHz
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8.2.4 Impact Test Results 'l'incobj
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I able 8.20 Comparison of the Reson
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'Phc invalidity of thc lumped mass
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Chapter 9 Concluding Remarks and Re
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general agreement. 5. An investigat
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mode, br example, might have been e
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References K I'o,lnt~n~. 'A Sludy o
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[21] .I.K. Vandiver, "Structo~ral D
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1431 D.J. Kartewcg and G. d-Vria "O
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1671 I..S. Marplo, "A NCW Autorepes
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(111 J. Zhou "Ocean Wave Simulation
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[Ill M.C. Ilallsm, N.J. Hcaf and L.
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Appendix A Selected Algorithms Tllr
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- M = the total mass of the slructu
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Suhrtituting qualion (A.5) in equal
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..3 Longuet-Higgins and Cokelet Smo
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Appendix B Sample Calculations Typi
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The dcnsity of ABS plsstic (p.,,) i
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C.l Calibration and Instrumentation
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D.l Mode Shape (Members 70 and 68 R
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D.2 Results for an Impact Initiated
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i W 4 P Li I 2: 5: E B '5 2- d :" i
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oa m 01 o or- QZ- oe- om Q Z ~ oo a
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D.3 MEM Damping Estimates for the D
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Table D.4 MEM Damping Estimate. fro
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4 - Memorial University of Newfoundland DAI

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