A027 Calculations and Stress Diagrams

BLOCK 1-DATA ITEM NO.: A027
BLOCK 2-DATA ITEM TITLE: CALCULATIONS AND STRESS DIAGRAMS

(See Attachment 1 to Data Item No. A027)
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BLOCK 3-DATA DESCRIPTION:

  1. Calculations and their revisions shall include examples, computer printouts, and worksheets, if used. Additional calculations required supporting the design not identified on Attachment 1 to Data Item No. A027 shall be provided in accordance with this Contract Data Requirement List.
  2. Engineering Design Calculations and diagrams shall be numbered. Each calculation shall reference applicable drawings by drawing number, drawing revision, and title.
  3. Calculations shall allow a reviewer to follow each step without difficulty. 
  4. Calculations including stress diagrams shall prove that the subject has been designed in accordance with the requirements of the contract. These calculations shall reflect design configuration. All symbols and abbreviations shall be identified and any diagrams, with their associated components, clearly labeled. Calculations shall include the following, where applicable:
    1. Assumptions used shall be stated and all references identified.
    2. A listing of system and equipment requirements.
    3. Applicable sections and Regulatory Body requirements.
    4. Calculation methodology or calculation methodology identification.
    5. A summary of calculation results, conclusions, recommendations and actual system, equipment or component sizes incorporated.
    6. Design load, working load, test load, assumptions as to manner of loading, such as live, dead, and alternating; assumed friction, materials (including specification section number), maximum stresses in each part such as compressive, tensile, shearing, and torsional developed by the load, and the factor of safety in each part.
    7. Information regarding characteristics under dynamic loading, where applicable, including natural frequencies of vibration, impact, ship motions, and other pertinent data.
    8. Summary loads shall include utilization factors and connected loads.
    9. Environmental considerations including temperature and motions. 
  5. Unique requirements shall be as identified on Attachment 1 to Data Item No. A027.
  6. If calculations are performed on a computer program, include a description of the program, input variables, and program assumptions. Explanation of how the computer printout results are used in the design shall be provided which identify a clear and traceable path of the analysis.
  7. All calculations prepared to support the ship shall be delivered in accordance with this Contract Data Requirements List.

BLOCK 4-REVIEW REQ.:

Allow 45 days for Government review and comment unless otherwise specified on Attachment 1 to Data Item No. A027.

BLOCK 5-SUBMITTAL SCHEDULE:

Calculations and their revisions shall be submitted concurrently with the drawings they support and their revisions IAW the Schedule(s), Data Item No. A001, and its revisions, and as specified on Attachment 1 to Data Item No. A027. R/ASR 20 DARC unless otherwise specified on Attachment 1 to Data Item No. A027. Revisions shall incorporate resolution of Government comments. 

T-AKE ATTACHMENT 1 TO DATA ITEM NO. A027: CALCULATIONS AND STRESS DIAGRAMS
ATTACH 1 TO DATA ITEM NO (BLOCK 1) DATA ITEM TITLE AND REFERENCE (BLOCK 2) DATA DESCRIPTION (BLOCK 3) REVIEW REQUIREMENTS (BLOCK 4) SUBMITTAL SCHEDULE (BLOCK 5)    
A027-01 PROPULSION SHAFTING AND BEARING ALIGNMENT ANALYSIS
  1. The Propulsion Shafting and Bearing Alignment Analysis shall include the following:
    1. A labeled line diagram of the shaft bearing system indicating dimensions, locations of bearings, types of bearings and assumptions used in performing the analysis.
    2. A table of bearing reaction influence numbers of each bearing for a one mil vertical change in position with respect to itself and all bearings in the system.
    3. A table showing bearing reactions and bearing pressure loads for each bearing for the following conditions, as applicable:
      1. Straight line, cold, in air.
      2. Straight line, cold, in water.
      3. Aligned, cold, in air.
      4. Aligned, cold in water.
      5. Aligned, hot, in water.
    4. The effects of individual and collective bearing weardown and thermal growth on bearing reactions shall be examined throughout the allowable range of weardown. The analysis shall verify the adequacy of the number, size, type and location of bearings for the aligned condition under all operating conditions.
  NLT 120 DPT start of propulsion shafting system manufacture; R/ASR 45 DARC.    
A027-02 ENDURANCE FUEL CALCULATIONS Calculations shall demonstrate that the ship meets the specified endurance fuel requirements.   NLT 45 DAC; NLT 320 DAC; R/ASR 20 DARC or the need for change is identified.    
A027-03 PROPULSION SYSTEM VIBRATION ANALYSIS Document the torsional, longitudinal, and lateral vibration analyses used to determine critical speeds, acceptable bearing spans, barred speed range, and .propeller characteristics. Include analyses and results.   NLT 120 DPT start of propulsion shafting system manufacture; R/ASR 20 DARC or the need for change is identified.    
A027-04 HVAC CALCULATIONS

The HVAC Calculations shall include the following:

  1. The calculations used to determine the design of the heating, ventilation and air conditioning (HVAC) systems and the air conditioning plant. Summer and Winter conditions shall be included.
  2. The chilled water load, electric load, and steam load, if applicable shall be identified. The size and number of air conditioning plants, refrigeration plants, HVAC systems, fans, heaters, and cooling coils shall be identified.
  3. HVAC Systems, duct sizing calculations, and refrigeration load and sizing calculations shall also be included.
  NLT 150 days; Semi-Annually thereafter, 5 DARP; R/ASR 20 DARC or the need for change is identified.    
A027-05 DYNAMIC LOADING APPROACH (DLA) ANALYSIS
  1. The Dynamic Loading Approach (DLA) shall present seakeeping and three-dimensional finitelement analyses for the following conditions consistent with the loading manual;
    1. Full load plus service life allowance
    2. Minimum operations
    3. Based on an assessment of intermediate load conditions the two conditions found to produce stresses closest to the design allowable stresses considering all stations shall be evaluated in DLA or as recommended by ABS.
  2. The analyses shall be based on long-term North Atlantic Ocean wave statistics and spectral shapes, and the specified operating profiles and heading probabilities. The report shall include the potential for bottom and bowflare slamming shall be evaluated and its effects included. The dynamic loads shall be based on the ship’s extreme long-term response. In addition to hull girder bending moments and shear forces, external hydrodynamic pressures on the hull, internal tank pressures, dynamic loads from vehicles and cargoes, and inertial loads of the hull structure shall be included in the analysis. Maximum stress results shall be compared to material allowable stress levels and buckling criteria as a means of assessing structural adequacy. Fine mesh finite element analysis of local structure shall be performed for critical locations as determined by the 3-D global analysis and as required for receipt of DLA notation. 
ABS approval required. Allow 45 days for Government comments. Concurrent with submittals to ABS; Final shall include ABS approval.    
A027-06 SPECTRAL FATIGUE ANALYSIS A spectral fatigue analysis shall demonstrate a crack free structure for the specified service life and operability in open seas. The analysis shall include the long-term North Atlantic Ocean wave statistics and spectral shapes, and the specified operating profiles and heading probabilities. Damage accumulation under cyclic loading shall be determined using the Palmgren-Miner linear cumulative damage rule and recognized industry standard S-N curves corresponding to two standard deviations below the mean. Fine mesh detailed structural models shall be developed for local regions in the ship’s structure that are to be assessed for fatigue. Regions for evaluation shall include regions of high stress and structural discontinuities, such as deck openings and end bracket connections, and the junction between longitudinal stiffeners of primary structure and primary transverse supporting structure including web plate cutouts for the longitudinals. Other highly stressed regions induced by fluctuating loads as identified from the DLA analysis shall be evaluated. The fatigue analysis shall demonstrate a 40-year service life. The fatigue analysis shall be reviewed by and approved by ABS. From this analysis, typical details used on the ship subjected cyclic loading shall be provided in a booklet with their associated fatigue life assessment. ABS approval required. Allow 45 days for Government comments. Concurrent with submittals to ABS. Final shall include ABS approval.    
A027-07 BOTTOM AND BOWFLARE SLAMMING ANALYSIS Bottomed bowflare slamming loads are to be considered for assessing the strength of the sideshell and bottom plating and stiffening system in the forward region. The effects of slamming loads on the hull girder bending moments are also to be considered for assessing strength. ABS approval required. Allow 45 days for Government comments. Concurrent with submittals to ABS. Final shall include ABS approval.    
A027-08 ENGINE INTAKE AND EXHAUST SYSTEM PRESSURE LOSS CALCULATIONS Calculations shall demonstrate that the intake and exhaust system losses are within the limits specified by the engine manufacturer.   Concurrent with Engine Intake and Exhaust System Arrangement Drawings, Data Item No. A028-27 and its revisions.    
A027-09

CARGO MOVEMENT SYSTEMS FAULT TREE ANALYSIS (FTA)

SOW C 1.2.1

The FTA(s) shall be presented in detail, at the component level, where appropriate, to allow Government personnel to assess the methodology and verify the results. An FTA shall also be applied at the system level for all shipboard cargo handling systems in accordance with the IEC 61025. All predicted FTA problems and critical items shall be reported. Plans for the timely resolution of problems and criticalities shall be included in the report. The Government will approve the Ordnance Movement and Securing Systems part of the Cargo Movement Systems Fault Tree Analysis based on technical content NLT 60 DAC; NLT 240 DAC; R/ASR NLT 30 DARC or the need for change is identified.

Addressee

NAVSEA 

TOTAL

Reg/Repro

0/1

1/5

Reference: DRL A027 31 January 2002