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Matched Legal Cases: ['art 01', 'art 2', 'art 11', 'art 5', 'art 6', 'art 7', 'art 8', 'art 19', 'art 28', 'art 4', 'art 7', 'art 5', 'art4', 'art 2', 'arts 6', 'art 8', 'art 05', 'art 05', 'art 28']

Vol09 Pt01 Issue 01 Submarine Structures | Strength Of Materials | Corrosion
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DEF(AUST)5000Vol 09 Pt 01 Iss 01
Dated: 12th Oct. 2009 Replacing/Superseding Nil
Volume 09 Submarine System requirements
Part 01 Submarine Structures
Usage: Maritime Commonwealth of Australia 2009 This work is copyright. You may download, display, print and reproduce this material in unaltered form only (retaining this notice) for your personal, non-commercial use within your organisation. All rights are reserved. Requests and enquiries concerning reproduction and rights should be addressed to the Manager, Legislative Service, AusInfo: GPO Box 1020, CANBERRA ACT 2601 or by e-mail to: Cwealthcopyright@dofa.gov.au
DEF(AUST)500&Vol09 Pt 01-lss 01
Sponsor MRS-CMA Audit Document Format Requirements
Signed: Name: P. F. King Appointment:
Principal Naval Architect - Directorate of Submarine Engineering
MRS - Configuration Management Authority
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Assistant Director Pass Technidil Content
Signed: Name: G. K. Watson Appointment: Principal Naval Architect - Directorate of Submarine Engineering Date: ............
Signed: Name: G. K. Watson Appointment: Principal Naval Architect - Directorate of Submarine Engineering Date: ....
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Director Approve Technical Content
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Signed: Name: Andrew Horobin
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Uncontrolled when printed or downloaded. Refer to web-site: htt~://defweb.cbr.defence.qov.au/home/documents/navvcoll.htm
DEF(AUST)5000Vol 09 Pt 01 SecIss 01
1 Scope ................................................................................................................................................ 5 1.1 Life Cycle .................................................................................................................................. 5 1.2 What is Covered ....................................................................................................................... 5 1.3 What is Not Covered................................................................................................................. 5 2 Documents ........................................................................................................................................ 6 2.1 Applicable Documents .............................................................................................................. 7 2.2 Referenced Documents ............................................................................................................ 8 3 DEFINITIONS, ACRONYMS AND ABBREVIATIONS ...................................................................... 9 3.1 Definitions ................................................................................................................................. 9 3.2 Acronyms ................................................................................................................................ 10 3.3 Abbreviations .......................................................................................................................... 10 4 Background ..................................................................................................................................... 11 4.1 Significance to RAN ................................................................................................................ 11 4.2 Consequences of Poor Performance or Hazard ..................................................................... 11 5 Functional and Performance Requirements .................................................................................... 12 5.1 General ................................................................................................................................... 12 5.2 Loads ...................................................................................................................................... 12 5.3 Pressure Hull Safety Factors .................................................................................................. 13 5.4 Overall Structure ..................................................................................................................... 14 5.5 Structural Elements................................................................................................................. 14 5.6 Watertight and Oil Tight Structure........................................................................................... 17 5.7 Materials ................................................................................................................................. 17 5.8 Fabrication .............................................................................................................................. 18 5.9 Welding ................................................................................................................................... 19 5.10 Non Destructive Examination.................................................................................................. 19 5.11 Maintainability ......................................................................................................................... 20 5.12 Signature................................................................................................................................. 20 6 DESIGN AND PRODUCT CONSTRAINTS..................................................................................... 21 6.1 Specific Design/Engineering Constraints................................................................................ 21 6.2 Navy Practice Constraints....................................................................................................... 21 6.3 Navy Personnel Constraints ................................................................................................... 21 6.4 Navy Logistic Constraints ....................................................................................................... 21 6.5 Australian Industry Constraints ............................................................................................... 21 6.6 Legislative Constraints............................................................................................................ 21 6.7 Interoperability Constraints ..................................................................................................... 21 6.8 Commonality Constraints........................................................................................................ 21 6.9 Regulatory Constraints ........................................................................................................... 21 7 Deliverables (DIDs) ......................................................................................................................... 22 7.1 General ................................................................................................................................... 22 7.2 Tender Deliverables................................................................................................................ 22 7.3 Pre Contract Deliverables ....................................................................................................... 24 7.4 During Contract Deliverables .................................................................................................. 24 7.5 Contract Deliverables.............................................................................................................. 24 7.6 Manufacture ............................................................................................................................ 24 7.7 Test Regime............................................................................................................................ 24 7.8 Maintenance/Hull Survey ........................................................................................................ 24
This document specifies high level structural requirements for RAN Submarines. It is generally based on the supposition that acceptable rules and requirements for the particular submarine hull design basis are currently in existence. The set of structural design rules, codes and standards employed for a particular submarine must be authorised in accordance with Navy regulatory requirements. In cases where the design deviates from this MRS Part, the designer is to itemise and justify non adherence for these requirements. Reference to any document/drawing also implies reference to any other relevant document/drawing cited therein. The requirements of this standard shall take precedence over all documents quoted herein. Where anomalies occur in the documents quoted this should be brought to the attention of the MRS Configuration Management Authority.
The document may not cover all aspects of submarine structural design. The onus on the designer is always to use good practice and best engineering judgement to ensure that the whole structure is fit for purpose and safe to personnel, the public and the environment.
The following documents are called up in this document. When applying this DEF(AUST)5000 document, the user is required to use the dated version if specified, or otherwise negotiate with the sponsor a suitably dated version for each applicable document. In accordance with DI(G) LOG 4511 Defence Policy on Materiel Standardisation document selection shall be based on the following order of precedence. Noting that in situations where no other standard adequately addresses the ADOs requirements, Australian Defence Standards are to be used in preference to other standards. Government, operational and/or technical imperatives can override preference to other standards:
Australian Defence Documents
ABR 6492 Navy Technical Regulations Manual SUBSAFE Series DEF(AUST) 5000 Vol 2 Part 2 - General requirements for RAN Submarines DEF(AUST) 5000 Vol 9 Part 11 Watertight Integrity and Recovery from Flooding DEF(AUST) 5000 Vol 3 Part 5 - RAN Welding Standard DEF(AUST) 5000 Vol 2 part 6 - General Shock Requirements DEF(AUST) 5000 Vol 2 part 7 Classified Shock Requirements - General DEF(AUST) 5000 Vol 2 part 8 Vibration
Australian DOD specifications. http://intranet.defence.gov.au/ - policy / documents Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp
DEF(AUST) 5000 Vol 2 part 19 RAN Engineering Drawing Requirements. DEF(AUST) 5000 Vol 2 part 28 Ship Electronic Product Modelling. DEF(AUST) 5000 Vol 3 part 4 - Painting
Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa
DEF(AUST) 5000 Vol 9 Part 7 - Submarine Escape and Rescue DEF(AUST) 5000 Vol 9 Part 5 - Explosive Stowages in Submarines DEF(AUST) 5000 Vol 9 Part4 Submarine Hydrodynamics, Manoeuvring and Control DEF(AUST) 5000 Vol 9 Part 2 - RAN Submarines Hull Survey Requirements
Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp Australian DOD specification http://defweb.cbr.defence.gov.au/navysyscom/mrs/homepa ge.asp
General Specifications for Ships of the United States Navy, 1994 Ed.
Requirement definitions used throughout DEF(AUST)5000 documents are contained in the DEF(AUST)5000Vol 01 Pt 03MRS Definitions and Abbreviations. Additional definitions not currently provided in the fore mentioned reference are listed as follows: Minimum Collapse Depth (MCD) Nominal Collapse Depth is the depth at which the pressure hull as built has an acceptably low probability of collapse if taken there once, assuming that all allowable (by specification) departures from standards are adverse. is the depth at which pressure hull collapse is predicted by calculation assuming that material properties, structural scantlings and ring frame out of circularity are their nominated rather than minimum values. is the maximum depth, measured to the underside of the keel, to which the submarine shall be capable of unrestricted operation. is the sea water pressure at DDD.
Deep diving depth (DDD) Deep Diving Depth Pressure (DDDP) Watertight:
Structure that is watertight must withstand the designed head of pressure without deformation and without weeping or beading at seals or penetrations.
Airtight: Gastight
Structure that is airtight must withstand an overpressure test of 15 millibars. Structure that is gastight must withstand a vacuum test of 5millibars.
Structure that does not in any way contribute to the main structural strength or watertight integrity of the vessel. Examples of minor structure are linings and false deckheads, partitioning, lockers and furnishings and non-watertight bulkheads. Structure that does not contribute significantly to the strength of the vessel but does contribute to significant operational, OHS, water and airtight integrity. Examples of secondary structure are, External tanks structure not subject to full DDD pressure, Internal tanks structure not subject to full DDD pressure and Flats and decks. Structure that contributes significantly to the watertight integrity and strength of the vessel. Failure in this structure would lead to overall collapse of the submarine or to uncontrollable flooding. Examples of primary structure include pressure hull, pressure hull frames, watertight bulkheads including frames and shear plates, hatches and coamings, SUBSAFE boundary equipments
Critical Structure Structure within high stress areas of the pressure hull where FOS is approaching design limits. Critical structure is determined by design analysis or through test and examination of existing structure. Examples of critical structure may include junction of pressure hull with bulkheads or deep frames, junction of shear plates with bulkheads or pressure hull, junction of hatch coamings, conning or escape towers, SSEs or other large penetrations with the pressure hull, primary structure with known defects which increase local stress levels above original design stresses and any other structural discontinuities.
MCD DDD DDDP OCD DAR TRA UUC IP Lbp
Minimum Collapse Depth Deep Diving Depth Deep Diving Depth Pressure Operational Concept Document Design Acceptance Representative Technical Regulatory Authority Usage Upkeep Cycles Intellectual Property Length between perpendiculars
Safety Aspects. The design of the pressure hull is critical to the maintenance of the safety of the submarine crew through the full range of operating depths of the submarine. The design of secondary structure and equipment mounts is also critical to the maintenance of safety under a shock environment. Capability Aspects. The design of the pressure hull, secondary structure and equipment mounts is critical to the maintenance of operational capability following shock loads. The detail of the design to minimise the likelihood and impacts of corrosion is also critical to the ability to sustain the capability in a cost effective and timely manner. Environmental Aspects. Ensures sufficient strength to prevent an environmental hazard in the case of a minor collision.
Poor design can lead to catastrophic loss of the submarine or loss of life. Poor detailed design can also lead to expensive and drawn out repairs to structure to repair corrosion, weld failures or fatigue cracking which can create high cost of ownership and reduced submarine availability.
The operational conditions ie, operation area and required life for which the submarine is to be designed shall be as detailed in the OCD. The OCD shall define the required DDD and the design fatigue life of the pressure hull against diving cycles. RAN submarines shall be designed to withstand all the loads and environmental condition to which it may be subjected over its lifetime. The resulting stresses, deformation and failure after damage are to be within acceptable limits as appropriate to the calculation method employed.
5.2.1 5.2.1.1 5.2.1.2 5.2.1.3 5.2.1.4 5.2.1.5 5.2.1.6 5.2.1.7 5.2.1.8 5.2.1.9 5.2.2 5.2.3
Loading on structure as a minimum is to consider the following: hydrostatic and hydrodynamic pressure on the hull, pressure/ load due to internal fluid loadings, equipment and stowage, pressure/ load due to operational equipment, pressure/ load due to flooding after damage, environmental loads such as wind, green seas and ice, shock pressure loads and accelerations, rolling and pitching motions of the submarine and accidental loadings for example detonation of pyrotechnics or Special Forces weapons. Bottoming/docking submarine The resulting stresses from such loading shall be to a level of accuracy appropriate to the calculation method employed. For the purpose of calculation, the submarine loading to be considered is to include the maximum combined static and dynamic loads applied with and without End of Life (EOL) growth margins. If any other conditions are more severe then this is also to be considered. The calculation procedures are at the discretion of the designer but subject to the approval of the DAR. Regardless of the procedure used the initial imperfections and residual stresses expected during construction are to be taken into account in all relevant calculations. Shock Underwater weapons can produce damage to the hull by shock and whipping effects. If the explosion is in the near vicinity of the hull, the effect can be catastrophic. Requirements of the OCD and DEF(AUST) 5000 Vol 2 Parts 6 and 7 shall be satisfied. In order to avoid rupture of structure resulting from underwater explosion the following design guidance should also be employed: Avoid hard spot which can cause stress concentration, Avoid large difference in stiffness of adjoining members, Ensure good continuity of girders and other structural members, Avoid use of unsymmetrical stiffening, Do not employ brittle materials in the hull structure, associated fittings and pressure tight enclosures exposed to external seawater pressures, 12
5.2.5 5.2.5.1 5.2.5.2 5.2.5.3 5.2.5.3.1 5.2.5.3.2 5.2.5.3.3 5.2.5.3.4 5.2.5.3.5
5.2.5.3.6 5.2.5.3.7 5.2.5.4 5.2.5.5 5.2.6 5.2.6.1 Adequately support the hull fittings, Shock clearances shall be provided where required, Pressure hull material and weld shock survivability shall be demonstrated by bulge explosion testing or another method deemed appropriate by the DAR. Compliance to performance criteria after exposure to shock at the levels detailed in the OCD shall be demonstrated by OQE to the extent deemed suitable by the DAR. Vibration Consideration is to be given to structural vibration either from cyclic sea loads, machinery or other sources. Appropriate measures are to be taken to eliminate high stress or resonance resulting from such phenomenon. Further requirements are provided by DEF(AUST) 5000 Vol 2 part 8 Vibration. Docking The keel and hull structure shall be designed to withstand the loads imposed by the worst docking condition, taking account of any overhang at bow or stern. Limiting docking conditions imposed by the hull structure are to be identified on the docking drawings. Damage Strength and watertight integrity of the submarine structure following damage due to abnormal loadings must be assessed. The type and extent of damage due to military action will be as detailed in the OCD. The extent of collision damage to external non-pressure hull plating is to be taken as: Length Width 4 percent Lbp anywhere along the external tank structure inboard up to but not including the pressure hull plating
5.2.8 5.2.8.1 5.2.8.2 5.2.8.3 5.2.8.3.1 5.2.8.3.2 5.2.8.4 5.2.8.4.1
The extent of grounding damage is to be taken as: Length 10 percent Lbp anywhere forward of amidship
Pressure Hull Safety Factors
The chosen order of failure and the factors of safety against failure are to be consistent with a well proven pressure hull design methodology. The rationale used for the selected factors shall be documented and subject to acceptance by the TRA. The factors of safety shall be developed in conjunction with the selected builder with due regards for the actual manufacturing capabilities relative to circularity, straightness, frame tilt and available materials. An important criterion to be satisfied in the selection of the factors of safety for the submarine structure shall be the minimising of self weight. As a minimum, design factors of safety for the pressure hull shall consider residual stresses, hull circularity, frame and plate tolerances as follows: Initial yielding not causing instability (typically 1.3 DDD) Frame yielding due to out of circularity (typically 1.75 DDD) Axi-symmetric yielding (typically 2.0 DDD) Local instability (typically 4.0 DDD) Global instability (typically 4.5 DDD) In-plane compressive and/or shear stresses within plates Primary and secondary stiffening members subject to axial compression and shear.
5.3.2 5.3.2.1 5.3.2.2 5.3.2.3 5.3.2.4 5.3.2.5 5.3.2.6 5.3.2.7
5.3.3 Cyclic stresses shall be at a level which does not incur fatigue cracking in the primary or secondary structure at any stage through life. Diving cycles shall be as defined in the OCD.
Hull construction details shall not adversely affect the quiet running of the submarine. Hatches, fittings, topside gear, and piping shall be designed and installed to be free of rattles. Hull attached protuberances shall be hydrodynamically shaped to minimise the generation of flow noise. Structural details, such as size of panels or relatively long thin struts connected to plating, shall be designed to be as resonance-free as possible, both locally and generally. Every effort shall be made to minimize the number of pressure hull penetrations. Hollow shafts and masts that penetrate the pressure hull shall withstand an internal pressure equal to the pressure at minimum design collapse depth. Holes shall have smooth boundaries, free from notches or re-entry angles from which cracks may be propagated. In general, holes in structure shall be circular. Where circular openings are not practicable, the corner radii of rectangular openings in pressure hull shell plating shall be designed to minimise stress concentration. If the size or location of an opening is such as to impair the strength of an important structural member, measures shall be taken to reduce the unit stress in way of the hole. Drain and air holes shall be provided to avoid the entrapment of water pools or air bubbles within tanks and bilges. Openings with portable covers shall be provided for access to equipment requiring maintenance outside of docking availabilities and for anode replacement. Access to such equipment shall not require cutting of structure. Replacement of anodes shall not require cutting in close proximity to the pressure hull. Particular attention is to be paid to the bilges because of the history of general wastage and microbiologically induced corrosion found there. Where possible the bilges should be sited in areas of low stress. Alternately consideration should be given to the use of thicker plate to provide an increased allowance for corrosion. Any pressure tight enclosures exposed to external seawater pressure shall be designed to avoid sudden collapse or sited to minimise the effects of implosion on surrounding structure, equipment, piping etc.
5.5.1 5.5.1.1 5.5.1.2 5.5.1.3 5.5.1.4 5.5.1.5 5.5.2 5.5.2.1 5.5.2.2
Pressure Hull The pressure hull, all trunks and other types of structure penetrating the pressure hull shall be of approved material. A representative number of randomly selected sites shall be ultrasonically inspected for possible cracking into the pressure hull prior to delivery and as part of the in service hull survey program. Any discontinuities discovered ultrasonically shall be pursued to their extremities. Submarine pressure hull structure to be designed to a minimum factor of safety of collapse depth over DDD. An assessment of the consequences of an impact by an exercise torpedo on the pressure hull shall be undertaken. Pressure Hull Frames Pressure hull frames, and structure acting as pressure hull frames, shall be located within the tolerances specified. Framing tolerances shall be designed for local stiffness, to resist panting, shock, and vibration and support the shell plating against wave impact. 14
5.5.2.3 5.5.2.4 5.5.2.5 5.5.2.6 5.5.2.7 5.5.3 5.5.3.1 Struts shall be so designed that they will not tend to tilt the frames when subjected to explosive loading. Framing in way of torpedo ejection pumps or cylinders shall be arranged to allow full free-flow of water to the inlets of the pumps or cylinders. The pressure hull framing shall be strengthened in addition to normal frame requirements, as necessary, to support the local loads exerted by the various components located in the space. The attachment of structure such as tank tops, lead pocket boundaries and foundations, to the edges of pressure hull frame flanges shall be accomplished by using full penetration welds. Attachments to the edges of pressure hull frames shall be kept to a minimum. External Hull Plating (excluding Pressure Hull Plating) Seams and butts of shell plating shall be full penetration welded joints. Plating shall be secured to frames, floors, tanks, and longitudinals by welding. An accurate fit shall be obtained between all members, and the designed form of all surfaces of plating and supporting framework shall be maintained. Plate thickness shall be retained within tolerances. Location and sizing of the main ballast tank flood holes shall minimize residual water in these tanks. The flooding area for ballast tanks shall be large enough to ensure that the allowable stress for the ballast tank structure will not be exceeded when the tanks are blown at the specified air blow rate. Stanchions Stanchions shall be designed to withstand the most severe probable combination of forces to which they will be subjected. The connections at the heads and heels of stanchions shall be sufficient to develop the full strength of the stanchions. Where it is necessary to fit portable stanchions, the bolted connection shall develop the full strength of the stanchion in the appropriate direction of loading. No other holes for bolts, threaded connections, or for any other purpose shall be made in stanchions. Bulkheads Bulkheads are to be designed elastically. The load is to be based on the test head that the bulkhead is to withstand and if exposed to DDD this shall be a pressure equivalent to Minimum CD. Other loads are to be considered taking into account the dynamic effects of tank filling and the effects of fluid motion due to ship motion. Due account is to be taken of in-plane loads on bulkheads such as heavy equipment and water pressure such that buckling of plating or stiffeners do not occur. Where transverse bulkheads connect to the hull they are to be designed to resist underwater explosion at the shock level specified in clause 2.1.2. The structure is to be designed such that neither the hull nor the bulkhead structure ruptures prematurely following significant plastic deformation that could be expected. Watertight structural bulkheads shall provide support to the pressure hull, decks, machinery, and equipment, and serve as a water-containment boundary between compartments. Bulkheads shall be designed to provide adequate strength for the submarine as a whole and shall withstand the following loads: Design hydrostatic heads. Dead loads due to mass of structure and equipment and due to docking. Design shock loads. Loads induced by supporting the pressure hull when subject to combined loading of submergence and shock. 15
5.5.4 5.5.4.1 5.5.4.2 5.5.4.3
5.5.5.2 5.5.5.3
5.5.5.4 5.5.5.5 5.5.5.5.1 5.5.5.5.2 5.5.5.5.3 5.5.5.5.4
5.5.5.6 5.5.5.7 Transverse bulkheads shall be continuous through platforms. Attachments to bulkheads for the purpose of supporting local masses shall be made so as not to impair the strength or tightness of the bulkhead. Insert and margin plates, special framing and stiffening shall be fitted as necessary to distribute local stress, and, as far as practicable, the attachments shall be made to the special framing and not directly to the bulkhead. Primary stiffeners shall be continuous for the full width of bulkhead. Generally, stiffeners shall be fitted on only one side of a bulkhead. Butts in stiffeners shall not be located in regions of high bending stress, insofar as practicable. Wherever practicable, bulkhead stiffeners shall be kept out of passageways, showers, washrooms, and water closet spaces. Doors and other openings shall be located so that as few stiffeners as practicable are cut, and the structural efficiency of the bulkhead is not impaired. Where necessary, chafing plates, castings, or half-rounds shall be fitted to protect the structure from the whip of the anchor chains. Stiffeners on chain locker bulkheads shall be fitted on the side opposite the chain. Non-tight structural bulkheads are those which support platform decks, machinery, or equipment, but do not serve as a containment boundary. Provisions shall be made to prevent damage due to radial and longitudinal hull contraction due to submergence. Provision shall be made to prevent damage caused by the longitudinal and radial contraction from the combined loading of both submergence and shock. Bulkheads supporting noise-generating equipment shall not be attached to stanchions which are connected to pressure hull frames. Decks and Platforms. Platform plating shall be of watertight construction, but not required to withstand pressure. Coamings, or a method of sealing shall be provided in the platform decks around openings for groups of pipes and cables to prevent incidental water spilling into the spaces below. Sufficient clearance shall be maintained between the coamings and resiliently hung piping passing through to eliminate the possibility of sound shorts. Drainage of deck water shall be provided from the platform decks to the bilges. Portions of platform decks shall be portable to permit removal of complete equipments which are sized to pass through the logistics hatch without disassembly. Portable or hinged section of platform decks shall be provided where access is required. These sections shall be rattleproof. The connection used to join the deck structure to the hull structure shall be designed to allow for hull flexure during depth changes with a minimum of joint-induced noise and to minimize transfer of such noise as may be generated through the hull to the water. Casing The casing shall be designed for wave-slap loading The structure shall be designed with a minimum safety factor of two for elastic instability of a member under stresses caused by wave-slap. The casing shall also be provided with rattleproof hinged or portable sections to provide access to all parts under the casing. Vent holes shall be sized to the minimum which will permit submergence in the time specified. Sufficient drain holes shall be provided to permit the casing to drain completely when surfacing without exceeding stability limits.
5.5.5.8 5.5.5.9 5.5.5.10 5.5.5.11 5.5.5.12
5.5.5.14 5.5.5.15 5.5.6 5.5.6.1
5.5.6.2 5.5.6.3 5.5.6.4
5.5.7 5.5.7.1 5.5.7.2 5.5.7.3 5.5.7.4 5.5.7.5
5.5.8 5.5.8.1 Fin The fin shall be free flooding with flooding and venting openings to permit submergence in the time specified in the OCD. Venting openings shall be located and designed to minimize the entry of seawater from waves and spray. Fin scantlings including bridge shall be designed for a sea slap loading on the projected areas. The structure shall be designed with a minimum factor of safety of two for elastic instability of the member under stresses caused by wave-slap and shock. Foundations for diving planes may be part of the fin structure. Care shall be taken in the design to prevent deflection of diving plane supports or other fitted equipments from affecting alignment of periscopes and masts. Acoustic window foundations and supporting structural members shall have sufficient strength and rigidity to maintain fin integrity under wave-slap. Bollard, Anchoring and Mooring Structure supporting any bollard or deck used for anchoring, mooring or towing shall be designed such that the structure shall not fracture before the cable breaking load is reached. Control Surfaces and Hydroplanes The rudder and stock shall be designed for the maximum shock and hydrodynamic loadings.. The structural arrangement shall be conducive to ease of access for construction and preservation. Keel Although keels do not significantly contribute to the strength, they experience similar longitudinal stress levels. The design of the keel shall ensure that stress concentrations are reduced to a minimum, appropriate grade of material selected and that appropriate measures are taken to ensure that crack propagation would be terminated prior to reaching the pressure hull. Masts Masts are to be designed to ensure that they provide adequate stiffness and strength for the equipment they support. Account is to be taken of all vibration excitations and it is to be ensured that no resonant frequencies occur. The submerged speeds at which the masts will be used are defined in the OCD.
5.5.8.2 5.5.8.3 5.5.8.4 5.5.8.5 5.5.8.6 5.5.9 5.5.9.1 5.5.10 5.5.10.1
5.5.11 5.5.11.1
5.5.12 5.5.12.1 5.5.12.2
Watertight and Oil Tight Structure
Watertight or oil tight structure shall not leak when subjected to pressure of the specified fluid, equivalent to the design head on the boundary. Tightness, in any degree, shall be attained by positive means such as welding or gaskets/seals (for mechanical fastened structure only). Stuffing tubes, flanged joints, or stuffing boxes shall be provided, as necessary, to safeguard the tightness of the bulkhead or deck wherever wiring trunks, pipe tunnels, or shaft tunnels terminate at the bulkhead or deck..
The selection of material for the submarine structure shall take into consideration the existing technology and infrastructure available to form and weld the material. The material selected in the design of the ship is to be appropriate to its location within the structure and the environmental condition in which the ship has to operate. 17
5.7.3 5.7.4 The materials used in the construction of the ship are to be manufactured and tested in accordance with ISO or equivalent standards. In addition to any other criteria deemed necessary to meet OCD requirements, the materials proposed for the pressure hull structure should meet the following criteria regarding mechanical properties: High yield strength High toughness levels Ability to withstand extreme deformation at high strain rates Low susceptibility to stress corrosion cracking Resistance to high stress low cycle fatigue Resistance to corrosion or loss of properties at environmental extremes. Forgings and Castings The materials proposed for forgings and castings connected to the pressure hull shall have similar properties to the pressure hull material while also proving resistant to the corrosion and erosion mechanisms associated with flowing or stagnant sea water under the specified environmental conditions. They shall also be suitable for the proposed method of attachment to the pressure hull without increasing the potential for corrosion. Materials Protection All material is to be protected in accordance with DEF(AUST) 5000 Vol 3 Pt 04 Painting and Vol 3 Pt16 Cathodic Protection as applicable. Coatings in highly corrosive areas (eg Bilges and battery compartments) shall be individually qualified by testing. Coatings for use in conjunction with anechoic tiles or radar absorbent materials shall be individually qualified by testing. Adhesives and procedures for attaching anechoic tiles shall be individually qualified by testing. The hull and ballast tanks are required to be cathodically protected. Where dissimilar materials are employed measures are to be incorporated to preclude galvanic corrosion. Corrosion margins employed in the design of the structure are to be clearly identified in design documentation. If for any reason the structure can not be preserved in accordance with specified requirements then an additional corrosion allowance is to be incorporated in the design.
5.7.4.1 5.7.4.2 5.7.4.3 5.7.4.4 5.7.4.5 5.7.4.6 5.7.5 5.7.5.1
5.7.6 5.7.6.1 5.7.6.2 5.7.6.3 5.7.6.4 5.7.6.5 5.7.6.6
Hull circularity and straightness of hull segments shall be achieved consistently to the required tolerances using proven and qualified fabrication control processes. These controls should utilise well designed jigs and fixtures that accept and hold the hull plate segments in precise positions to enable proven weld procedures and sequences to be used to fabricate the circular hull form with a minimum of residual stress at welded joints. In the fabrication and erection of hull structure, particularly welded structure, discontinuities, undercuttings, notches, nicks, or other mechanical damage which might initiate or propagate cracks or points of weakness leading to possible total failure of the structure shall be avoided. Where local structure is subjected to significant loading, then the structure is to be fully integrated in to the main hull structure. Where part of a structural member has to be cut away, the reduction in strength shall be compensated for.
5.8.5 5.8.6 Discontinuous members on opposite sides of a through member shall line up back-to-back within specified limits of error in offset. Cold working of high tensile and high yield strength steels shall be restricted as much as practicable. Because of the cold working effects of punching and shearing, notches cut in high strength steels shall be cut by drilling or oxygen cutting only. Such material that has been cold-worked by shearing shall be removed by machining, oxygen cutting, or grinding. Flanges and webs of pressure hull frames or bulkhead stiffeners shall not be drilled or punched for attachments of gratings, platforms, foundations, fittings and hangers. Sharp or ragged edges of exposed structure, where likely to injure personnel or equipment, shall be removed. Corners in passageways shall be rounded to present a finished appearance. Where portions of bulkheads, decks, or other hull structures are left incomplete during the process of work, temporary fastenings or supports shall be fitted as necessary to prevent damage to the rest of the structure. Structure which will be inaccessible after erection shall be fully preserved. The designer shall define all dimensional tolerances in conjunction with the selected builder. The designer shall set requirements for the quality and traceability of all materials and components used during the fabrication process. These requirements shall be subject to approval by the DAR.
5.8.7 5.8.8 5.8.9
5.8.10 5.8.11
Welding of RAN submarines shall be in accordance with DEF(AUST) 5000 Vol 3 Part 05. All welds for primary structure including frame fabrication and shell connections shall be full penetration welds. Partial penetration joints shall not be used in any structure designed to withstand DDD pressure. For design of welded joints, reference shall be made to the appropriate design or equipment Standards. The weld classification, positioning qualification procedures and NDE requirements are at the discretion of the designer but they shall consider the technical capability of the selected builder and minimise the need for additional infrastructure. Wherever possible the welds shall be placed in areas of low stress to allow the use of lower strength consumables and minimise weld preparation requirements while meeting the other criteria for the submarine structure materials. Where this is not possible the welds shall have similar performance or better than the base material. All welding and related processes shall be subject to approval by the DAR. During fabrication a summary of the weld repairs undertaken shall be provided to the CoA on a regular basis at intervals to be agreed. Fabrication contractors and subcontractors shall be accredited iaw DEF(AUST) 5000 Vol 3 Part 05 requirements.
5.9.6 5.9.7 5.9.8
NDE shall be in accordance with standards approved by the DAR to provide assurance that no surface or subsurface defects exist in any plane ie transverse or longitudinal An NDE plan detailing the scope of examination to be undertaken on welds shall be developed by the designer and endorsed by the DAR. The NDE contractor shall be independent of the fabricator. Proposed NDE procedures shall be submitted to the DAR for endorsement. NDE personnel shall be subject to proficiency testing prior to starting and periodically when engaged. Results shall be available for audit by the TRA. 19
DEF(AUST)5000Vol 09 Pt 01 Iss 01 5.11
Access is to be provided for structural maintainability. The maintenance policy shall aim for maximising the number of sea days while minimising the through life cost. Areas with a high likelihood of corrosion shall be designed to enable inspections to be conducted with minimal equipment removal. Corrosion/metal loss allowances (general and localised) shall be provided for each component of the primary and secondary structure. Minor structure (brackets etc) attached to the outside of the pressure hull shall be attached using doubler plates to minimise the requirements for removal and reattachment of the structure to the hull through life. When designing the layout of anechoic tiles consideration shall be given to the necessity to remove tiles in some areas to provide access for external NDE of areas with difficult access and a high likelihood of internal corrosion or fatigue induced cracking.
The geometric shape of the exposed surface of the hull above water shall be designed to reduce signatures to a level consistent with the requirements in the OCD. The geometric shape of the hull shall be designed to reduce both the self radiated noise signature and reflective sonar signatures to a level consistent with the requirements in the OCD.
A statement by the DAR confirming compliance of the design with agreed requirements and rules shall be provided. All deliverables are to be presented as hard copy and as computer files (format agreed between the contractor and TRA) on CD. CoA ownership and/or access to IP and CoA access to designer support services throughout the life of the Class shall be subject to TRA agreement.
Tender Deliverables
Structural Report: A structural calculation report demonstrating that the submarine has been designed to a consistent set of recognised naval material standards as appropriate and acceptable to the TRA shall be provided. The report shall provide details of theoretical approach and methodology employed. Calculations and analyses in English are to employ proven methods. For each main area of analysis, the report shall also include a discussion of calculation and analysis methods used, evidence of their accuracy and a discussion of assumptions made. The report shall cover as a minimum hull, decks, frames, bulkheads, towers and all other structure subject to operational loadings. Strength calculation shall include all hatches and covers that are subject to load. The report shall provide calculations showing that the pressure hull strength and local scantlings comply with the requirements of the design rules. The calculations shall provide a description of the longitudinal weight distribution of adequate frame increment for the full length of the submarine. The worst case loading conditions taking into account the full combination of loading factors shall be applied to the structural elements. In the case of an existing design, the calculation shall include the original design and highlight the changes to the parent hull structure with the impact of the highlighted change. Separate calculations shall be provided for masts and periscopes to demonstrate that the structural design with regards to strength, stiffness and vibration avoidance of resonant frequencies fully meets the design requirements. Separate calculations shall be provided to demonstrate that frequencies of hull vibration are in avoidance of the resonant frequencies of major sources like shaft and propeller. A report on the performance of hull against underwater shock and a report on post damage Residual Strength Assessment (RSA). Design Data The structural report shall be supported by the following set of DAR approved design data: Source and data for environmental and military loading. Calculations for fatigue, local strength and buckling of primary and secondary structure and foundations for major equipment. Finite Element model determine with a level of detail and accuracy acceptable to the DAR Finite Element Analysis input and output data Acceptable stress and deformation limits 22
7.2.1.5 7.2.1.6
7.2.1.7 7.2.1.8 7.2.2 7.2.2.1 7.2.2.2 7.2.2.3 7.2.2.4 7.2.2.5 7.2.2.6
7.2.2.7 7.2.2.8 7.2.2.9 7.2.2.10 7.2.2.11 7.2.2.12 Material selection and supporting test results Circularity measurement method and results Design and manufacturing tolerances for primary and secondary structure. Calculations supporting acceptability of loads applied during docking. Weld plans (showing locations of welds) Collision Safety Assessment covering survivability of the pressure hull and ballast tank structures in the event of a collision. Should also cover the consequences of a exercise torpedo colliding with the hull. Drawings: The following DAR approved structural drawings shall be provided: General Arrangement; Midship Section; Profile and Decks; Shell Expansion; Watertight Bulkheads; Deep and Ring Frames; Longitudinal Section; Pillars and Girders; i). Fore end construction; j). Aft end construction; Machinery Seating; Conning tower structure Escape tower and rescue seat structures Casing and Support Structure; Fin and Mast Support Structure; Rudders and supporting structure; Propeller support structure; Sonar Dome and Appendages; Drawings as noted in the ILS Certification Matrix; and Any other drawings required by the TRA. The purpose of these drawings is to assist the evaluation of the principal characteristics of the structural design. The drawings shall be approved by the DAR and will form one of the base documents of the construction contract. All drawings shall show full details of material thickness, welding detail etc. Cross-references and revisions to relevant drawings shall be clear and concise. All additions and changes to major structural elements such as frames and watertight bulkheads detailing all connection methods, structural pillars etc and impact on existing design structure shall be highlighted. A full 3d CAD model of the submarine iaw DEF(AUST) 5000 Vol 2 Part 28 Ship Electronic Product Modelling. 23
7.2.3 7.2.3.1 7.2.3.1.1 7.2.3.1.2 7.2.3.1.3 7.2.3.1.4 7.2.3.1.5 7.2.3.1.6 7.2.3.1.7 7.2.3.1.8 7.2.3.1.9 7.2.3.1.10 7.2.3.1.11 7.2.3.1.12 7.2.3.1.13 7.2.3.1.14 7.2.3.1.15 7.2.3.1.16 7.2.3.1.17 7.2.3.1.18 7.2.3.1.19 7.2.3.1.20 7.2.3.2
7.2.3.3 7.2.3.4
DEF(AUST)5000Vol 09 Pt 01 Iss 01 7.3
Pre Contract Deliverables
A design disclosure document on the structural design shall be provided to establish the credibility of the designer to provide a quality design that complies with proven submarine structural standards and methodologies. This design disclosure shall provide the preliminary calculations of the proposed structure using pressure and shock loads at DDD and CD. This shall include the design philosophy and application of the safety factors proposed and their traceability to the standards and requirements. The designer shall provide evidence where their design philosophy has been applied to similar submarine design that has been accepted, and design validation data from trials.
During Contract Deliverables
In the detailed design/construction phase, further details of data, calculations and drawings capturing all the up-to-date information of the capability shall be provided. There shall be a gradual delivery of structural reports as they are completed.
The final structural calculation report(s) together with complete set of approved as fitted structural drawings shall be provided.
Where as built measurements show the design tolerances have been exceeded a re-assessment of the relevant calculations shall be undertaken and submitted to the DAR. For each submarine a report documenting the dimensional tolerances of the submarine structure achieved during build and highlighting any deviations from design tolerances.
7.7.1 7.7.1.1 7.7.1.2 7.7.1.3
Tank tightness test Prior to submergence tests, boundaries of tanks shall be tested with seawater. Tightness tests are performed by applying water pressure equivalent to the specified design head of the structure. Tightness tests shall not be performed until structural work, including any structural attachments which might affect the tightness of the structure, is complete. Permanent access fittings and closures shall have been installed. Vacuum test A vacuum test of the whole submarine and of all compartments and bulkheads which may be subjected to DDD or CD pressure shall be conducted to prove boundary integrity in way of hatches and penetrations prior to any dived tests. First of Class tests A test plan shall be produced to conduct strain gauging of the hull of the First of Class during its first dive to DDD. A report shall be produced comparing the results obtained with those predicted and highlighting any significant variations. A test plan shall be produced for monitoring accelerations and strains of the pressure hull during First of Class Shock Trials.
7.7.2 7.7.2.1
Maintenance/Hull Survey
To ensure maintenance of adequate through life strength, an ongoing Survey program shall be undertaken iaw DEF(AUST) 5000 Vol9 Pt 02 Submarine Hull Survey. Circularity measurements of pressure hull plating shall be taken, both at build and following structural modifications, throughout those portions of the pressure hull and pressure hull appendages that are intended to be circular. The designed survey program shall be consistent with UUC requirements and shall detail acceptable in-service and through life corrosion limits, survey of high stress welds and structure and metal loss repair procedures.
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