SHIP STRUCTURE COMMITTEE 2005

1 NTIS # PB2005- SSC-443 DESIGN GUIDELINES FOR DOUBLER PLATE REPAIRS OF SHIP STRUCTURES This document has been approved For public release and sale; its Distribution is unlimited SHIP STRUCTURE COMMITTEE 2005 Ship STRUCTURE COMMITTEE RADM Thomas H. Gilmour U. S. Coast Guard Assistant Commandant, Marine Safety and Environmental Protection Chairman, Ship STRUCTURE COMMITTEE Mr. W. Thomas Packard Director, Survivability and Structural Integrity Group Naval Sea Systems Command Senior Vice President American Bureau of Shipping Mr. Joseph Byrne Director, Office of Ship Construction Maritime Administration Mr. Gerard A. McDonald Director General, Marine Safety, Safety & Security Transport Canada Mr. Kevin Baetsen Director of Engineering Military Sealift Command Dr. Neil Pegg Group Leader - Structural Mechanics Defence Research & Development Canada - Atlantic Mr.

2 Jaideep Sirkar (SNAME T&R Chair) Society of Naval Architects & Marine Engineers CONTRACTING OFFICER TECHNICAL REP. Mr. Chao Lin / MARAD TBD / NAVSEA Mr. Robert Sedat / USCG EXECUTIVE DIRECTOR Lieutenant William A. Nabach U. S. Coast Guard SHIP STRUCTURE SUB- COMMITTEE AMERICAN BUREAU OF SHIPPING DEFENCE RESEARCH & DEVELOPMENT ATLANTIC Mr. Glenn Ashe Mr. Yung Shin Mr. Phil Rynn Mr. William Hanzalek Dr David Stredulinsky Mr. John Porter MARITIME ADMINISTRATION MILITARY SEALIFT COMMAND Mr. Chao Lin Mr. Carlos Setterstrom Mr. Richard Sonnenschein Mr. Joseph Bohr Mr. Paul Handler Mr. Michael W. Touma NAVAL SEA SYSTEMS COMMAND TRANSPORT CANADA Mr. Jeffery E. Beach Mr. Allen H. Engle Mr. Charles L. Null Mr. Val Smith UNITED STATES COAST GUARD Mr. Rubin Sheinberg Mr. Robert Sedat Mr. H. Paul Cojeen Captain Ray Petow Technical Report Documentation Page 1.

3 Report No. SSC-443 2. Government Accession No. PB2005- 3. Recipient s Catalog No. 4. title and Subtitle Design Guidelines for Doubler Plate Repairs of Ship Structures 5. Report Date August 2005 6. Performing Organization Code 7. Author(s) Sensharma, , Dinovitzer, A., Traynham, Y. 8. Performing Organization Report No. SR-1438 9. Performing Organization Name and Address BMT Designers & Planners, Inc. 10. Work Unit No. (TRAIS) 2120 Washington Boulevard Suite 200 Arlington, VA 22204 11. Contract or Grant No. 13. Type of Report and Period Covered Final Report 12. Sponsoring Agency Name and Address Ship STRUCTURE COMMITTEE Coast Guard (G-MSE/SSC) 2100 Second Street, SW Washington, DC 20593 14. Sponsoring Agency Code G-M 15. Supplementary Notes Sponsored by the Ship STRUCTURE COMMITTEE .

4 Jointly funded by its member agencies. 16. Abstract The use of doubler plates or doublers has become routine for temporary ship repairs. It is the preferred method for ships structural repairs for plate corrosion due to its relative ease and low cost of installation over the more costly permanent welded plate insert repair. A lack of performance data and engineering design guidance are the reasons that repairs with doublers are currently considered only temporary. This project was created to develop a set of guidelines for designing and applying doubler plate repairs to ship structures. The guidelines were established using the following criteria: various stress analyses, buckling strength, primary stress assessment, corrosion types and rates, weld types, and doubler plate fatigue and fracture assessment.

5 Studying and understanding doubler plate repair performance by comparison to that of the primary hull performance allows critical operational decisions to be made with greater ease and confidence. However, the ultimate goal of this project was to establish the design and limitations on the applications of doubler plate repairs for surface ships. 17. Key Words Doubler, Fatigue, Fracture, Buckling, Corrosion, Ships 18. Distribution Statement Distribution is available to the public through: National Technical Information Service Department of Commerce Springfield, VA 22151 Ph. (703) 487-4650 19. Security Classif. (of this report) Unclassified 20. Security Classif. (of this page) Unclassified 21. No. of Pages 123 22. Price $ paper - iv - CONVERSION FACTORS (Approximate conversions to metric measures)

6 To convert from to Function Value LENGTH inches meters divide inches millimeters multiply by feet meters divide by VOLUME cubic feet cubic meters divide by cubic inches cubic meters divide by 61.

7 024 SECTION MODULUS inches2 feet centimeters2 meters multiply by inches2 feet centimeters3 multiply by inches3 centimeters3 multiply by MOMENT OF INERTIA inches2 feet2 centimeters2 meters divide by inches2 feet2 centimeters4 multiply by inches4 centimeters4 multiply by FORCE OR MASS long tons tonne multiply by long tons kilograms multiply by pounds tonnes divide by pounds kilograms divide by pounds Newtons multiply by

8 PRESSURE OR STRESS pounds/inch2 Newtons/meter2 (Pascals) multiply by kilo pounds/inch2 mega Newtons/meter2 multiply by (mega Pascals) BENDING OR TORQUE foot tons meter tonnes divide by foot pounds kilogram meters divide by foot pounds Newton meters multiply by ENERGY foot pounds Joules multiply by STRESS INTENSITY kilo pound/inch2 in in)

9 Mega Newton MNm3/2 multiply by J-INTEGRAL kilo pound/inch Joules/mm2 multiply by kilo pound/inch kilo Joules/m2 multiply by vTable of Contents EXECUTIVE SUMMARY ..3 INTRODUCTION ..5 SCOPE OF STUDY ..7 CURRENT PRACTICES ..8 Classification Societies ..8 Installation Guidance ..9 Summary of Additional Remarks and Opinions Expressed During Class Society Class Society 1 ..13 Class Society 2.

10 14 Class Society 3 ..14 Shipyards ..15 Type of damage repaired ..18 Location of doubler plate repair ..18 Expected life span (permanent/temporary)..18 Size and thickness of doubler plates ..18 Doubler plate corner radii ..18 Use of slot Shipyard/ship owner TECHNICAL APPROACH ..22 INTRODUCTION ..22 Eigenvalue (Linear) Buckling Fatigue and Fracture Analysis ..23 EIGENVALUE LINEAR BUCKLING ANALYSIS ..25 Finite Element Model ..25 Geometry ..26 Material Model ..27 Loading ..27 Buckling Analysis Results ..27 Effect of Corrosion Features on Buckling Strength of Stiffened Panels Analysis Baseline ..27 Buckling Load Factor ..29 Effect of Doubler Size and Thickness ..33 Doubler Thickness Effect of Corrosion.