design considerations for aluminum hull structures - Ship Structure ...

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SHIP STRUCTURECOMMITTEEThe SHIP STRUCTURE COMMITTEE is constituted to prosecute a researchprogram to improve the hull structures of ships by an extension of knowledgepertaining to design, materials and methods of fabrication.RADM W. F. Rea, III, USCG, ChairmanChief, Office of Merchant Marine SafetyU, S. Coast Guard HeadquartersCapt. J. E. Rasmussen, USNHead, Ship Engineering DivisionNaval Ship Engineering CenterCapt. T. J. Banvard, USNMaintenance and Repair OfficerMilitary,Sealift Commandt!;!e:.S. DillonOffice of Ship ConstructionMaritime AdministrationMr. C. J. L. Scho.efer,Vice PresidentAmerican Bureau of ShippingSHIP STRUCTURE SUBCOMMITTEEThe SHIP STRUCTURE SUBCOMMITTEE acts for the Ship Structure Committeeon technical matters by providing technical coordination for the determinationof goals and objectives of the program, and by evaluating and interpreting theresults in terms of ship structural design, construction, and operation.NAVAL SHIP ENGINEERING CENTERU. S, COAST GUARDMr. P, M. Palermo - ChairmanMr, J. B. O’Brien - Contract AdministratorMr. G. Sorkin - MemberMr. H. S. Sayre - AlternateMr. I. Fioriti - AlternateMARITIME ADMINISTRATIONMr. F. Dashnaw - MemberMr. A. Maillar - MemberMr. R. Falls - AlternateMr. Raymond F. Coombs - AlternateAMERICAN BUREAU OF SHIPPINGMr. S. G. Stiansen - MemberMr. F. J. Crum - MemberOFFICE OF NAVAL RESEARCHMr. J. M. Crowley - MemberDr. W. G. Rauch - AlternateLCDR C. S. Loosmore, USCG - SecretaryCDR C. R. Thompson, USCG - MemberCDR J. W. Kime, USCG - AlternateCDR J. L. Coburn - AlternateNATIONAL ACADEMY OF SCIENCESMr. R. W. Rumke, LiaisonProf. R. A. Yagle, LiaisonSOCIETY OF NAVAL ARCHITECTS & MARINEENGINEERSMr. T. M. Buermann, LiaisonAMERICAN IRON AND STEEL INSTITUTEMr. J. R. Lecron, LiaisonBRITISH NAVY STAFFNAVAL SHIP RESEARCH & DEVELOPMENT CENTERMr. A. B. Stavovy - AlternateMILITARY SEALIFT COMMANDMr. R, R. Askren - MemberLt. J. G. Ervin T. Powers. USNR -MemberDr. V. Flint, LiaisonCDR P. H. H. Ablett, RCNC, LiaisonWELDING RESEARCH COUNCILMr. K. H. Koopman, LiaisonMr. C. Larson, Liaisonviii
I. INTRODUCTIONThis report summarizes the results of a study of the present technicalstate of the art to determine the feasibility of economical constructionand operation of a large high density deadweight carrier constructedentirely of aluminum.The present level of technology in the aluminum industry is sufficientlyadvanced to warrant active consideration of the use of aluminumfor a large bulk carrier. This study is given further impetus by therecent emphasis of life cycle cost, which has provided the techniquesnecessary to justify higher initial expenditures where the potential forlong-term economic benefits exist.BackgroundAluminum alloys suitable for use in a marine environment have beenavailable for approximately 30 years, offeri~ significant advantages inreducing structural weight and hull maintenance. However, the unitmaterial cost of aluminum alloys is presently between 5 and 6 times thatof mild steel. The use of aluminum alloys generally reduces hull structuralweight by approximately SO per cent relative to steel, so that the totalmaterial cost of an aluminum hull will be between 2-1/2 and 3 times thatof a comparable steel hull. Since aluminum construct~on does not generallyresult in a significant reduction in the labor costs for hull construction,the higher material cost produces a corresponding increase in overall constructioncost which must be passed on to the purchaser. This factor hasgenerally restricted the use of aluminum to the following marine applications:o High-speed hull forms, particularly planing hulls, where thehigher hull cost can be justified on the basis of superiorperformance.o Special applications where the resistance of aluminum tospecific corrosive environments is required.o Superstructures , where the reduction in topside weight justifiesthe higher material cost.o Applications where light hull weight is essential to suitdraft limitations or lifting requirements.k addition to the foregoing restrictions, the introduction ofaluminum alloys into the marine industry has encountered technical difficultiesin some areas, resulting from either the basic characteristicsof aluminum alloys, or from misuse of these alloys during fabrication.Among lrtheprobl~mslf experienced with aluminum marine applications are:o Early problems with the introduction of aircraft-type alloysand fastening methods which were unsuited for a marineenvironment.o Problems with welding prior to the introduction of the ~000series alloys. Although these problems have been largely
Page 5: CONTENTSI.. II.III.Iv.v.VI ●VII.I
Page 9: LIST OF FIGURES(Cent’d)FIGURE NO.
Page 13: art in fabricating and maintaining
Page 16 and 17: MONTEROSSO GRANA /17VALGRANA / CARA
Page 18 and 19: -8-Numerous references have been re
Page 20 and 21: .10.TABLE 2. Mechanical Properties
Page 22 and 23: TABLE 2 Mechanical Properties of Al
Page 24 and 25: TABLE 3 Mechanical Property Limits
Page 26 and 27: -16-l?igures5, 6, 7 ati 8 present f
Page 28 and 29: -18-ti-’”’-”-””””-L
Page 30 and 31: -20-60 .r---.— ..,.— -——,L-
Page 32 and 33: .22-each stress level, rate of load
Page 34 and 35: -24-!Z456-H321 = 0.485083-H321 = 0.
Page 36 and 37: -26-(c)Members with partial or cont
Page 38 and 39: -28-AllOyS 5083 and 54.56(~ content
Page 40 and 41: -30-The previous paragraphs have de
Page 42 and 43: -32-The problem of cargo hold abras
Page 44 and 45: -34-The question of residual stress
Page 46 and 47: .36-Each alloy was given a relative
Page 48 and 49: -38-GENERAL OBSERVATIONSFYior to a
Page 50 and 51: -40-The question of comparative imp
Page 52 and 53: -42-(d)(e)Poor quality welds due to
Page 54 and 55: -44-The ABS criteria noted above we
Page 56 and 57: -46-DNV would consider fatigue in e
Page 58 and 59: -48-is less, for the exposed side s
Page 60 and 61:
Equation (2):-50-Hu1l SMa~um = Hull
Page 62 and 63:
-52-Another aspect of vibrations wh
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-54-000000000Bottom Shell PlateSide
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-56-at the deck and keel. This stre
Page 68 and 69:
-58-AT is the change inUT= Thermal
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-60-SUl@!ARYAll parties contacted f
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-62-(c)(d)(e)(f)T~e exterior side o
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TABLE 12 Aluminum Bulk Carrier - Su
Page 76 and 77:
.66-INSUT.ATION AND SHEATHINGShell8
Page 78 and 79:
-68-(b)(c)(d)(e)(f)(g)(h)(i)(j)At l
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-70-IIF.INSTALLATION OF SYSTEMS AND
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Rudder Assembly -carrier should be
Page 84 and 85:
-74-(b)MechanicalTensile Strength 6
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-76-(e)The steel piping must be of
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-78-Other Piping Systems and Valves
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-80-struetion for the aluminum hull
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-82-Large heavy type machine~ must
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suffers attack in an alkaline envir
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-86-REPAIRSObtaining proper repairs
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-88-The design of the midship s~cti
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-90-assuming the increase is applic
Page 102 and 103:
LIGHT SHIP WEIGHT ESTIMATE-92-In or
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-94-TABLE 20 Aluminum Bulk Carrier
Page 106 and 107:
TABLE 22 Trim and StabilityFull Loa
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-98-TABLE 24 Price of Steel Bulk Ca
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GaseNumber. . . -.,- .TABLE 27 Comp
Page 112 and 113:
-1o2-TABLE 28CarriersComparison of
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12 ---n..T.[T7%l,=LEGS IU ORF=ErY
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-106-such as iron ore, on two of th
Page 118 and 119:
-108-7)is,zg~ gg~5e mzz~E’4E!~K2j
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-11o-(a)(b)(c)(d)Inerting system fo
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-112-fatigue, particularly in the p
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-114-2k* Installation of Systems an
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-116-LIST OF REFERENCES(7)Fatigue P
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-11.8-LLST OF REFERENCES(Cent’d)(
Page 130 and 131:
-120-ADDITIONAL SOURCES OF INFORMAT
Page 132 and 133:
-122-redistribution of the still wa
Page 134 and 135:
-124-APPENDIX BEXCERPTS FROMRULES A
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-126-92.07-10(d)(~) Interior stairs
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-128-~gE1+0102030- .. ..—405060
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ectintyclassification4KEYWORDSROLEL
Page 142:
SHIP STRUCTURE COMMITTEE PUBLICATIO
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