BIENNIAL REPORT
OF THE
SHIP STRUCTURE COMMITTEE
U.S. Coast Guard Headquarters
Washington, D.C.
SHIP STRUCTURE COMMITTEE
July 1968
Dear Sir:
The attached Biennial Report covers the current status of the Ship Structure Committee program, the Committee's method of operation, the members who contribute to its success, a plan for
future areas of research and a list of documents published since
the 1966 Report. Technical portions of this publication are a
continuation of a series of technical progress reports that began with the publication in 1946 of the Final Report of the Ship
Structure Committee's predecessor, the Board to Investigate the Design and Methods of Construction of Welded Steel Merchant Vessels.
Any questions, comments, criticisms, or other matters pertaining to the report should be addressed to the Secretary, Ship Structure Committee.
This report is being distributed to those individuals and agencies associated with and interested in the work of the Ship Structure Committee.
Sincerely,
D. B. HENDERSON
Rear Admiral, U. S. Coast Guard Chairman, Ship Structure Committee
MEMBER AGENCIES: ADDRESS CORRESPONDENCE TO:
UNITED STATES COAST GUARD SECRETARY
NA VAL SNIP SV ST EMS C OMMAND SNIP STRUCTURE COMMITTEE
MILITARY SEA TRANSPORTATION SERVICE U.S. COAST GUARD HEADQUARTERS
MARITIME ADMINISTRATION WASHINGTON D.C. 20591
CONTENTS
Page
Chapter I
Authority for the Ship Structure Committee i
Chapter II
Organization 3
Chapter III
Current Ship Structure Committee Organization Directory 8 Chapter IV
Projects 12
Chapter V
Future Program for Ship Structure Committee Research . 16 Chapter IV
American Council of the International Institute of
CHAPTER I
AUTHORITY FOR THE SHIP STRUCTURE COITTEE
The Ship Structure Committee was reestablished on 27 June 1968 by
the Secretary of Transportation. A reprint of the authority follows: To: Commandant, U. S. Coast Guard
Subject: Establishment of Ship Structure Committee
The standing interagency advisory committee known as the "Ship Structure Committee" is hereby approved.
PURPOSE. The purpose of the Committee is to conduct an aggres-sive research program which will, in the light of changing technol-ogy in marine transportation, improve the design, materials, and construction of the hull structure of ships by an extension of know-ledge in those fields for the ultimate purpose of increasing the safe operation of ships.
3 MEMBERSHIP. The Committee is composed of
-A representative of the Commandant, U. S. Coast Guard, Depart-ment of Transportation
A representative of the Commander, Naval Ship Systems Command, Department of the Navy
A representative of the Commander, Military Sea Transportation Service, Department of the Navy
A representative of the Administrator, Maritime Administration, Department of Commerce
A representative of the President, American Bureau of Shipping CHAIRMAN. The member representing the Commandant, U. S. Coast Guard, is the Chairman of the Committee.
SPONSOR. The Commandant, U. S. Coast Guard, is the sponsor of the Committee.
FUNDING. Funds for the work of the Committee shall be obtained by the transfer of funds from each of the participating
organiza-tions listed in paragraph 3. The Committee shall control and account for the funds transferred to it.
REPORTS. The Committee shall submit an annual report of its activities to the Commandant, U. S. Coast Guard. This report
and an accounting of expenditures. In addition, the Committee shall disseminate pertinent information to all parties having an interest in the building and operating of ships and to research investigators.
The Committee is established in accordance with Executive Order No. 11007, Part 95 of the Regulations of the Office of .the Secretary of Transportation, and Department of Transportation Order No. 1100.22.
I consider that the establishment and use of the Ship Structure Committee is in the public interest in connection with the perform-ance of the duties of the Department of Transportation and the Coast Guard.
Is/John E. Robson
Acting Secretary of Transportation
Roles:
-3-CHAPTER II ORGANIZATION
The Ship Structure Committee is assisted in its operation by a Ship Structure Subcommittee and an Executive Croup. In addition, technical advice is provided to the Ship Structure Committee by the National Academy of Sciences utilizing its Ship Research Committee.
Description of the Ship Structure Committee Organization The Ship Structure Committee (SSC):
Membership: One member from each of the participating agencies, to be nominated by the Secretary of his department, and to be appointed by the Secretary of the Depart-ment of Transportation.
Roles: Establish policies and rules for operation. Review
objectives, budgets and reports forwarded by the Ship Structure Subcommittee. Provide general guid-ance to the program. Obtain funds for the program. The Ship Structure Subcommittee (SSSC):
Membership: Members shall comprise two representatives from each of the participating agencies, plus a member from the Office of Naval Research and a contract administrator from the Naval Ship Engineering
Center. Members shall be nominated by each agency's
member of the Committee, and shall be appointed by the Chairman of the Committee.
Liaison members may be appointed by the Chairman of the Committee as mutually agreed by the Committee and groups with whom liaison is desired.
The Subcommittee acts for the Ship Structure Committee on technical matters, providing tech-nical coordination for the entire program. Its primary functions are:
to determine the goals or objectives of the program and the priorities which should be assigned to them.
to develop and execute research programs to meet the goals.
Roles:
(c) to evaluate and interpret the results of research programs in terms of ship struc-tural design, construction and operation. C. The Executive Group:
Membership: The members shall be members of the Ship Struc-ture Subcommittee. The group shall comprise one
representative from each member agency and a con-tract administrator from the Naval Ship Engineer-ing Center.
The Executive Group representation is provided for by the following:
Division Head, Naval Ship Engineering Center Chairman
Assistant Repair Officer
Military Sea Transportation Service Project Engineer
Office of Research & Development Maritime Administration
Senior Surveyor Hull Technical Staff
American Bureau of Shipping
Secretary of the Ship Structure Committee United States Coast Guard - Secretary Head Structures Branch
Naval Ship Engineering Center Contract Administrator
Acts for the Ship Structure Committee and conducts the business of the Ship Structure Committee
pro-gram. This is an administrative group concerned
with funding, budgeting and administrative super-vision of the program.
D. The National Academy of Sciences-National Resea.rch Council (NAS-NRC)
The NAS-NRC is the scientific and engineering research advisory group for the Ship Structure Committee program. It provides advice and assistance to the Ship Structure Committee during the establishment of
-5--objectives and priorities, in the development and execution of projects to meet those objectives, and in the interpretation and evaluation of
research results. It does this by:
Providing assistance and advice in determining realistic, specific objectives to which the program should be directed. Assisting in planning research projects to attain these
obj e.ctives.
Providing assistance and advice in selecting organiza-tions and personnel capable of carrying out the research projects.
Providing technical surveillance over such projects, and providing advice on the progress and direction of the work.
Preparing technical reports and summaries of research work relating to the Ship Structure Committee program.
Providing assistance and advice in evaluating and inter-preting the results of research.
The Ship Research Committee (SRC) is the group within the National Academy of Sciences which provides advisory service for the Ship Structure Committee. The SRC in turn is directed by the Maritime Transportation Re-search Board of the NAS-NRC. The Board is concerned with the broader as-pects of marine transportation. Hence, the work of the Ship Structure Committee is integrated with the total marine transportation picture.
Figure 11.1 gives the organizational structure of the Maritime Transportation Research Board.
National Academy of Sciences
Ship Operations Commit tee
Maritime Transportation Research Board
Trade and Economics
Commit t e e Fig. 11.1 Ship Research Committee Ship Acquisition Committee
Oper at ions
The focus of the SSC and its auxiliary committees, including
NAS-NRC, is the research program. The operations of these several groups concern the steps necessary to institute the several projects within the program, provide technical advice and guidance to the program, and assure widespread dissemination of the research results to interested technologists.
In performing th.e above operations the SSC through the SSSC and
with the advice of NAS-NBC periodically sets up an objective toward
which all projects should be aimed.. Each year recommendations are made to the SSC of a series of research projects aimed at this objective.
These recommended projects are selected from suggestions received from not only NAS-NRC but from the SSC, cther groups within the SSC ccmplex
and through unsolicited proposals submitted directly to the Secretary of the SSC.
The list of recommended projects is submitted to the SSSC by NAS-NRC together with a description of the work to be done, an indication of
the results that may be anticipated, an analysis of ho this project relates to the general program objectives and an estimate of the prob-able annual cost. In order to assist in the establishment of new pro-jects a prospectus is prepared for bidding purposes.
The SSSC in conjunction with the Executive Group reviews these recommendations in relation to available monies, degree of emphasis in
each area, and conformance to broad goals. Their recommendations are then transmitted to the SSC who ha final responsibility in matters of financing, suitability of projects to overall objectives, assurance of coordination of research projects, and degree of dissemination of re-search results.
The investigators conduct the actual research and prepare such rcports for the sponsor as are needed to adecuately report the progress or termination of the research. The NAS-NRC works closely with the investigators during the course of the research and in the preparation of the final report. After review of such reports by the NAS-NRC and SSSC they are forwarded to the Ship Structure Committee for approval and public distribution.
Organization Chart
of
Ship Structure Committee
RESEARCH PROJECTS
A
SHIP STRUCTURE
COMMITTEE
SHIP STRUCTURE SUBCOMMITTEE Technical Control Policy Making A A Fig. 11.2
t
Liaison EXECUTIVE GROUPAdministration & Funding
$
NAVAL SHIP ENGINEERING CENTER
Contract Administration NATIONAL ACADEMY OF SCIENCES SHIP RESEARCH COMMITTEE Technical Advice Amer i ca n Naval Ship Military Sea Bureau of Systems Command United States Maritime Transportation Sii i ppi ng U.S. Navy Coast Guard Administration Service U.S. Navy
CHAPTER III
CURRENT SHIP STRUCTURE CONNITTEE ORGANIZATION DIRECTORY Ship Structure Committee Membership
Rear Admiral D. B. Henderson, USCG, Chairman Chief, Office of Engineering
U. S. Coast Guard Headquarters Washington, D. C. 20591
Captain R. T. Miller, USN
Head, Ship Engineering Division Naval Ship Engineering Center Department of the Navy
Washington, D. C. 20360 Captain T. J. Banvard, USN Engineer Officer
Military Sea Transportation Service Department of the Navy
Washington, D. C. 20390 Mr. E. Scott Dillon
Acting Chief, Office of Ship Construction Maritime Administration
Washington, D. C. 20235 Mr. D. B. Bannerman, Jr. Vice President - Technical American Bureau of Shipping 45 Broad Street
New York, N. Y. 10004
Commander Claude R. Thompson, USCG, Secretary Office of Engineering
U. S. Coast Guard Headquarters Washington, D. C. 20591
Ship Structure Subcommittee Membership Naval Ship Systems Command - U. S. Navy Mr. John J. Nachtshejm - Chairman
Mr. John Vasta - Contract Administrator Mr. George Sorkin - Member
Mr. Harrison S. Sayre - Alternate Mr. Ivo Fioriti - Alternate
Naval Ship Research and Development Center Mr. A. B. Stavovy - Alternate
-9-Ship Structure Subcommittee Membership--Continued. Office of Naval Research
Mr. J. M. Crowley - Member
Dr. William G. Rauch - Alternate
Maritime Administraticn
Mr. Frank Dashnaw - Member
Mr. Anatole Maillar - Member Mr. R. Falls - Alternate
Mr. W. G. Frederick - Alternate Military Sea Transportation Service
Lieutenant Commander R. T. walker, USN - Member Mr. R. R. Askren - Member
American Bureau cf Shipping Mr. G. F. Casey - Member Mr. F. J. Crum - Member U. S. Coast Guard
Commander Claude R. Thompson, USCG - Member Commander James L. Howard, USCG - Member
Lieutenant Commander Leroy C. Meiberg, USCC - Alternate Lieutenant Commander R. L. Brown, LSCG - Alternate
Ship Structure Subcommittee Liaison Representatives National Academy of Sciences - National Research Council Mr. A. R. Lytle - Director, Ship Research Committee
Mr. R. W. Rumke - Executive Secretary, Ship Research Committee American Iron and Steel Institute
Mr. J. R. LeCron
British Navy Staff
Mr. H. E. Hogben
Ship Structure Subcommittee Liaison Representatives--Continued Welding Research Council
Mr. K. H. Koopman, Director
Mr. Charles Larson - Executive Secretary
Members, Ship Structure Subcommittee - EXECUTIVE GROUP
Mr. John Nachtsheim, NAVSEC, Chairman Mr. Frank Dashnaw, MARAD
Lieutenant Commander R. T. Walker, USN, MSTS
Mr. G. F. Casey, ABS
Mr. John Vasta, NAVSEC, Contract Administrator Commander Claude R. Thompson, USCG, Secretary
SHIP RESEARCH COITTEE
Mr. M. L. Sellers, Chairman Dr. J. M. Frankland, Vice Chairman
Newport News Shipbuilding & Drydock Co. National Bureau of Standards (Ret) Members
Mr. William H. Buckley
Chief, Structural Criteria Bell Aerosystems Co.
Mr. B. B. Burbank
Bath Iron Works (Ret)
Dr. Don P. Clausing Senior Scientist
U.S. Steel Applied Research Center Mr. Donald P. Courtsal
Principal Hull Design Engineer
Dravo Corporation
Mr. A. E. Cox
LIlA Project Director Newport News Shipbuilding
& Dry Dock Co.
Mr. Francis V. Daly
Manager of Welding
Newport News Shipbuilding & Dry Dock Co.
Professor R. A. Yagle
Dept. of Naval Architecture & Marine Engineering University of Michigan
Mr. John F. Daizell
Senior Research Scientist Hydronautics Inc.
Professor J. E. Goldberg School of Civil Engineering Purdue University
Mr. Joseph E. Herz
Chief Structural Design Engineer Sun Shipbuilding & Dry Dock Co. Mr. G. E. Kampschaefer, Jr.
Manager, Application Engineering
ARNCO Steel Corp.
Professor Bryan R. Noton
Dept. of Aeronautics & Astronautics Stanford University
Dr. Stanley T. Rolf e Section Supervisor
U. S. Steel Applied Research Center
Mr. Merville Willis General Manager Ship Design Division Consultec, Inc.
MEMBERSHIP OF ADVISORY GROUPS (Ship Research Committee)
M. L. Sellers and J. M. Frankland - - ex officio members of all Advisory
Groups
Advisory Group I, Ship Strain Measurement & Analysis M. Willis - Coordinator W. H. Buckley A. E. Cox J. F. Dalzell J. E. Goldberg J. E. Herz
Advisory Group II, Ship Structural Design R. A. Yagle - Coordinator W. H. Buckley D. P. Courtsal E. Cox J. E. Goldberg J. E. Herz R. Noton
Advisory Group III, Metallurgical Studies S. T. Rolfe - Coordinator B. B. Burbank D. P. Clausing D. P. Courtsal V. Daly E. Kampschaefer B. R. Noton
CHAPTER IV PROJECTS
Description of Items in 1968-1969 Program
SR 153 - SHIP RESPONSE STATISTICS - Teledyne Corporation
Objective. To obtain long-term data on vertical bending moments exper-ienced by various types of ships operating on different routes. These data will enable the prediction of extreme values of these loads which, when appropriately combined with the other loads to which a ship is subjected, will establish the basis for rational design of the hull structure. Four ships have been instrumented during the course of this program. From past experience with analysis of the strain measurements, a minimum of two years duration for any one ship was found desirable to develop sufficient data for statistical analysis. The switching of trade routes for the WOLVERINE STATE from the Atlantic Ocean to the Pacific Ocean in 1967 has provided an opportunity to collect data on
the same ship in both oceans. The data collection for bending moment measurements, ship-borne wave measuring information, and slamming
pressure profiles will be continued through the 1968-69 winter season. This project is scheduled for termination in the spring of 1969.
SR 171 - SHIP STATISTICS ANALYSIS - Webb Institute of Naval Architecture Objective. First, analyze the data obtained-from full scale ship bend-ing-moment tests, correlate with sea state data and develop long term predictions of bending moment. Second, to compare model test data and full scale ship test data and determine correlation factors which will permit the projection of model test results into full scale design data.
SR 172 - SLM4J4ING STUDIES - Teledyne Corporation
Objective. To obtain full-scale ship data on loads and responses caused by slamming in rough weather. Bottom pressures, bow accelerations and hull stresses will be correlated with sea conditions to check the vali-dity of theoretical methods for predicting the incidence and magnitude
of slamming. The instrumentation has been aboard the WOLVERINE STATE for the past two years, so far no slamming has been recorded.
SR 174 - SHIP COMPUTER RESPONSE - Oceanics, Inc.
Objective. The purpose of this project is to develop suitable analy-tical and computational methods to predict ship dynamic response caused by ship-wave interaction. The first phase, now complete, was the develop-ment of the dynamic-response equations. The second phase, now underway and expected to be completed in 1968, is the development of a computational
-13-method to exploit the analytical development. The third phase will provide verification of the analytical-computational method by compari-son with available experimental data.
SR 177 - HIGH STRENGTH LOW-ALLOY STEEL WELDMENTS - Southwest Research Institute
Objective. The purpose of this project is to study the factors which
affect the adequacy of high-strength low-alloy steel weidments for commercial ship usage and environment. It encompasses the required
mechanical properties of the weidment; the appropriate welding
electrodes, acceptable welding processes, required welding procedures -and the qualification of the welding procedures. A means for evalu-ating the finished weldment, for evaluation of fatigue and for determin-ing the influence of corrosion will be studied by this research. The goal is a laboratory specimen and test which, with ccrrelation with large-scale specimens and tests, can be used to accept or reject pro-posed weidments. Phase I was a survey of current shipyard practice and procedures and a recornirendation for temporary repair practice. Large scale tests to determine weldment strength will be performed in Phase II. During Phase III a test procedure and specimen for eval-uating weldments will be developed and verified by comparison with
large scale tests of Phase II. The survey of phase I has been completed and a report is being written. Progress has started on phase II.
SR 180 - FRACTURE-STRAIN PROGRAM - Battelle Memorial Institute Objective. This project is intended to develop a computer program which will synthesize the several metallurgical and mechanical prop-erties and processes that contribute to fracture. Experimental and an-alytical research is being undertaken over a three-year contract period to describe a comprehensive analysis of fracture in ship materials. The project started in late 1967.
SR 182 - CONTAINER SHIP RESPONSE - Teledyne Corporation
Objective. To gather full scale data on a container ship with partic-ular emphasis upon torsion response of the "open deck". Longitudinal bending moment, transverse bending moment, torsion and rigid body ship motions will be measured and correlated with sea state. Sea state will be measured by expendable wave buoys. The ship selected is a modified C-4 hull operated by Sea Land, Inc. with some 83% of the main deck removed for container access. Research engineers will ride the ship during the winter of 1968-1969 to collect and analyze dàta. It
SR 183 - HULL GIRDER MODEL STUDY - Mithras Division of Sanders Associates, Inc.
Objective. To investigate the response of a hull girder as a composite
of separate elements by using a ship-like box girder model. The
res-ponse of this hull model, loaded in bending, should be tested past the buckling limit to failure, under flexural loads, under hydrostatic
loads, and then under a combination of these. In addition to establish-ing the ultimate or failure load, some of the variables that can be evaluated are the value of high-strength steels, and the effect of varying degrees of fabrication mismatch.
The first phase of this program is a feasibility study of the model and test procedure. Following the study, plans can be made to initiate the experimental program. It is anticipated that this pro-ject will continue for a period of about three years, the second phase will begin in the later part of 1969.
SR 184 - CHEMICAL TANK-BARGE DESIGN - Electric Boat Division of General Dynamics
Objective. To develop a suitable design procedure for large cylind-rical low-pressure liquid cargo tanks supported by ir.ultiple saddles and carried on barges. The project is divided. into three phases. Phase I, now in. progress, is a feasibility study to outline current design procedures, to define the tasic theory of approach and to pro-pose an experimental program to gain necessary data for application to the design of larger barges suitable for full ocean service. Phase
II is intended to be a data gathering period using existing full scale barges. Phase III will be the correlation of experimenta.l data with theoretical predictions and development of design criteria.
SR 185 - STRAICHTENflG DISTORTED FLDMENTS - Battelle Memorial Institute Objective. To find a suitable method of straightening ship structures which have warped during welding or have been damaged by- impact. The
complicating factor is that. flame straightening used so widely on con-ventional ship steels has a severe metallurgical effect on high-strength
low-alloy steels. The work originally intended, to last for about one year has been in progress for three months. It now appears that the work should be extended to cover additional areas and funds have been budgeted for 1969.
SR 186 - DELTA TEST VALIDATION - Lafayette College
Objective. A project sponsored jointly by Ship Structure Committee and the Pressure Vessel Research Committee of the Welding Research Council. is intended to develop a new test, "Delta Test," to determine the degradation of toughness and mechanical properties caused by welding.
-15-The initial report to PVRC indicates the Delta Test is indeed sensitive
to test temperature, parent material, weld procedures, etc., and, in addition, allows the fracture to follow a path of least resistance without bias from the loading system. Because of the possible
appli-cation to the High-Strength Low Alloy Steel Weidments project, a vali-dation test was initiated to include comparison of Delta Test results
with those from drop weight tests, explosion bulge tests, and Charpy
V-notch tests of plate, weld, and heat affected zone. This project is expected to complete in 1969.
SR 187 - SHIP RESPONSE DATA STUDY - Teledyne Corporation
Objective. To reduce to useable digital form the ten ship years of full scale data collected by the Ship Structure Committee. The pro-ject requires about one year for completion is divided into three
steps. Phase I is a study to determine who will use the data, what
type of data is needed and what the format of the data should be. Phase II will be development of the Computer program for recording the data in digital form and Phase III will be reduction of data to digital form.
CHAPTER V
FUTURE PROGRAM FOR SHIP STRUCTURE CONMITTEE RESEARCH
Goals
The long-range goals of the Ship Structure Committee are:
a. To aid the ship designer and builder respond to the rapidly changing demands of the marine phase of our transportation
system by sponsoring a research program of:
Developing rational design procedures and criteria,
Refining the theories of the strength of the hull girder,
Fostering design improvement by developing a wider selection
of materials, and
Improving hull fabrication procedures.
To pursue the goals stated above, research in three related but distinct areas will be performed; first, load and response studies where at-sea data on sea-way induced loads will be gathered on conventional ships, container ships and barges. This data will be correlated with weather data and compared both with theoretical values calculated by computer techniques and with model test data obtained from rough water tests of segmented models. Second, under structual design, rational design studies using computer techniques will be developed, failure areas will be analyzed, barge tank interaction will be studied and the basic theory of design will be checked by use of a large scale model of the ship's
hull. Third, under metallurgical studies, adequacy of high strength
steel alloys for ship application will be studied, basic mechanism of material failures will be researched, new materials such as reinforced plastics and aluminum are to be given emphasis, and test methods and procedures will be evaluated. Figure V.1 gives the planned distribu-tion of SSC projects for the years 1967-1971. Figure V.2 shows the grouping of the projects into study areas.
-17-SHIP STRUCTURE COITTEE PROJECTS
Note:
Height of bar - relative expenditure level.
SR Project Title 67 68 69 70 71 153 Ship Response Statistics
172 Slaimning Studies
171 Ship Statistics Analysis
174 Ship Computer Response
177 High-Strength Low-Alloy Steel Weidments.
180
Fracture Strain Program
182 Container Ship Response183 Hull Girder Model Study
184 Chemical Tank-Barge Design
185 Distorted Weldments
186 Delta Test Validation
- - Ship Reliability Analysis
187 Ship Response Data Study
- - Computer Design for Ships
- - Ultrasonic Guide for Weld Flaw Evaluation. .
- - Reinforced Plastics for Cargo Vessels.
- - Thermal Study
4
t
i
T
SHIP STRUCTURAL D ANALYSIS J DESIGNL
SHIP STATISTICS i ANALYSIS SR-171 r SLMIMING STUDIES SR-182i7
r
SHIP COMPUTER RESPONSE SR-174SHIP STRUCTURE SUBCOITTEE RESEARCH
1968 - 1969
IMPROVED HULL STRUCTURES i
-J
EHIJLL
GIRDER MODELSTUDY SR-1&2I3
t_,_..__
i-I-i--.'
CHEMICAL TANK BARGE DESIGN COMPUTER DESIGN FOR SHIPS THERMAL STUDY Fig. V.1 i METALLURGICAL HIGH-STRENGTH LOW-ALLOY STEEL WELDMENTS SR-177 FRACTURE STRAIN PROGR.AN SR-180 DISTORTED WELDMENTS SR-185L
ALUMINUM HULL ULTRASONIC GUIDE FEASIBILITY STUDY FOR WELD FLAW
EVALUATION CONTAINER SHIP REINFORCED PLASTICS DELTA TEST RESPONSE SR-182 FOR CARGO VESSEL!J VALIDATION SR-186
-19-LOAD AID RESPONSE STUDIES The scope of research for this phase is:
to obtain sea-way induced loads on conventional ships, container ships and barges with independent tanks,
to increase our understanding of the nature, level and distri-bution of the hydrodynamic loads on ship hulls (this includes
slamming and other sea-way loads), and
to determine correlation of ship model, mathematical simula-tion model and full-scale ship response to sea-way loads.
Item 1. Studies of Seaway Loads Aboard Ship
Objective. To obtain records of seaway induced stresses aboard ship suitable for statistical analysis and direct correlation to computer simulated models. Ten ship years experience under SR-153 and SR-172 are being analyzed statistically under SR-17l to make long term bending moment predictions on various ships plying different trade routes. Under a new project, Ship Response Data Study (SR-l87), the ten ship years of collected data will be processed and put in digital form permitting computer analysis of all the important information
such as fatigue and thermal cycles. This year under SR-l82 the coverage has been broadened to include data gathering on a container ship. In SR-182 it is intended that this data will be based on more accurate sea state information thus permitting the verification of the computer model simulation of SR-l74. During Phase 2 of SR-l84 we will gaher
stress data on independent tank barges operating in the inland waterway system to test basic design theory and extrapolate the information into full ocean criteria.
Item 2. Response of Ship Hulls to Slamming Loads
Objective. To measure the distribution, level and type of pressure load on hull structures caused by slamming, correlate these data with associa-ted sea and motion data and determine the elastic response of the hull to these impact loads. Compare the experimental results with those de-rived from extensive theory. Study the effect of hull form and of such hull structural characteristics as damping, framing, bottom design, etc. Current work in this research is under SR-172, "Slamming Studies" at Teledyne, Inc.
Item 3. Computer Simulation of Ship Response
Objective. To develop a mathematical simulation model of ships at sea. Under SR-174 a simulation model was to be developed, programmed on a computer and run to make predictions of maximum bending moments and bow
check against model test results conducted under SR-l65. Results of the
verified mathematical model.runs were to be fed into the Rational Ship Design Program (SR-175) to provide more realistic loads for the rational
analysis of hull structures. To study influence of hull flexibility
upon ships subjected to impulse loads, it was, also, intended to feed the results from the computer simulation into the ship stiffness program
developed under SR-173. Difficulty in the development of the simulation
model has been encountered; however, the study is continuing. Item 4. Model Testing
The model testing program which provided inputs to the Simulation Model SR-174 and Statistical Studies SR-171 is drawing to a close. Vertical and lateral wave bending moments were measured over a range of wave headings and drafts for the WOLVERINE STATE and the CALIFORNIA BEAR. At
present, additional model tests are not planned; however, should veri-fication of the Simulation Model require a wider range of vessel types, towing tank tests on other ship designs will provide the most timely support.
-21-STRUCTURAL ANALYSIS AND DESIGN The scope of research for this phase is:
To study the ultimate load carrying capacity of a ship's hull, To set up basis of rational design of ships to meet changing demands of modern transportation such as chemical cargoes or containers of various descriptions,.
To evaluate the use of other materials such as aluminum and reinforced plastics, and
To seek optimum distribution of hull material.
Research in the following project areas is intended to outline the scope described above.
Item 5. Study of Ultimate Strength of Ship's Hull
Objective. To determine the load carrying capacity of a hull by tests of a ship-like model of large scale. After tests and evaluation of results, factors of safety based upon ultimate strength can be used in developing design criteria. The initial part of this effort is a feasi-bility study of the model and model test procedure outlined in SR-183.
Item 6. Study of Chemical Carriers and Container Vessels
Objective. To study special problems influencing the hull struc.ture of chemical carriers and non-conventional vessels such as container ships whose hull has been altered to provide easy access. In chemical carriers
such as barges the liquids are often contained in independent tanks. Some products are heated to become liquids for handling, some gases are pressurized to form liquids, other gases are carried at atmospheric pressure, but at cryogenic temperatures to obtain a liquid state and other products are highly corrosive. Of particular interest are the forces imposed upon a tank by the tank supports and the contribution of the tank to the combined longitudinal strength of the tank-barge combi-nation. The problem of interaction of barge hull and independent tank are now under study in SR-184. In this study the design theory will be reviewed, load measurements taken and a design procedure developed. A
thermal study whose objective is to analyze the influence of variation in cargo temperatures is, also, in our program. Transport of both heated and refrigerated cargoes induces hull stresses caused by large tempera-ture fluctuations not only underway at sea, but, also, in the loading and unloading operations. The study of these changing stresses upon the fatigue life of the hull material will help determine criteria for hull design of chemical and refrigerated liquid carriers. In addition to
the normal operating problems the thermal study will consider the emer-gency case of rupture of the cargo containment tank and its potential hazard of reducing the temperature of the ships hull steel into its "nil ductility" range.
Item 7. Ship Reliability Analysis
Objective. To gather data on ship hull failures both of magnitude sufficient to endanger ship loss and those of size capable of on board
repair. The compilation of failures will be analyzed to determine
problem areas, oUtline research subjects to relieve the problem, deter-mine the influence of cyclic loads on load carrying capacity and check the
design criteria for adequacy.
Item 8. Computer Design for Ships
Objective. To develop a computer based design method for longitudinally framed ships. This project is an extension of the Rational Ship Design program for transversely framed vessels. (SR-l75) 1t is intended the work proceed in two steps with step one being an interpretive report of
the state of the art of investigators throughout the world and provide an outline of the best approach for computer solution. Second phase will be the development of the theory of solution and finally, the writing and checking of the computer program.
Item 9. Investigation of New Materials for Application to Cargo Ship Hulls
Objective. To investigate the application and feasibility of using
reinforced plastics and aluminum in a large ship's hull. Reinforced plastics have been used successfully in small craft hulls for many years and are
being considered for Navy craft of up to 200 feet in length.
In todays
market, filament wound sections and hollow core sandwich panels make theapplication of these materials to large ships seem reasonable and practical. Inherent advantages of plastics such as resistance to corrosion and light-weight-high-strength offer possibilities of use in superstructures, complex sections in the bow and stern and main hull girder.
Application of aluminum follows the same path as reinforced plastics. Experience with smaller craft, improvements in alloys, new fastening tech-niques and improved welding has signaled that a large ship may be built of
aluminum and operated successfully in competition with other ships. In both the reinforced plastics and aluminum studies a new and fresh approach
-23-METALLURGICAL STUDIES
The emphasis on the research in the materials area will be to:
Improve design by fostering a wider selection of materials, Study new test procedures to improve hull fabrication and quality of the finished weidment, and
Develop new fabrication techniques. Item 10. Brittle Fracture Research
As the culmination of many years of "brittle fracture" research the Fracture Strain Program (SR-180) at Battelle will join the several influences affecting fracture into a computer program enabling a com-prehensive study of that phenomenon. This basic research project is expected to run for three more years. The Simulated Performance Test program (SR-169) in which wide plates and stiffened plates were f rac-tured and analyzed, has been completed. A comprehensive report of the procedure and results is being written. Experience gained with SR-169 provided a basis for the tests necessary to prove the application of high-strength-low-alloy steel weldments of project SR-177.
Item li. New Materials Verification
As new materials come into use, methods of fabrication, non-destruc-tive tests and an allowable stress-considering such factors as fatigue-must be verified. Our high-strength-low-alloy steel weldment program
(SR-l77) is performing such a study for a group of 100 PSI yield strength steel alloys whose use is relatively new to the marine industry. As other materials are found feasible in design studies - such as aluminum and reinforced plastics - the tests of fabrication, repair methods and
so forth will require similar research before wide spread application is possible. In addition to the fabrication problems, repair procedures for both emergency and routine repairs must be developed and published for wide spread use in the areas of the world the ships travel.
Item 12. Test Development
Objective. To encourage development of suitable non-destructive tests to keep abreast of new materials, fabrication techniques, and changing designs. Delta Test Validation(SR-l86) is a program to develop a simple test - inexpensive and easy to perform - that will evaluate the toughness of a welded specimen. Mother project proposed for this year will develop
a guide for the evaluation of weld flaws by ultrasonics. This guide was proposed fo1lowng the success of our previous document Guide fnr Non-Destructive Tests of Welds in Ship Hull Structures SSC-l77 which, Ly th
number of copies requested, demonstrated a need for greater effort in the development of guides for evaluating the information gained from
testing. Project SR-l76, Quality Assurance, just completed and soon to
be published, developed a system for making a permanent magnetic tape
record of the readings taken by the operator of ultrasonic test equip-ment. Considering the growth in application of ultrasonics particularly
in the higher strength hull materials a permanent record method should prove valuable particularly to satisfy construction code requireiients.
-25-CHAPTER VI
AMERICAN COUNCIL OF THE INTERNATIONAL
INSTITUTE OF WELDING
The Ship Structure Committee, American Welding Society and the Welding Research Council make up of the American Council of the
International Institute of Welding. The council co-ordinates the par-ticipation of the U. S. Government and U. S. universities and industrial concerns in the work of the International Institute of Welding, 11W.
11W has the following commissions which meet annually: Commission I - Gas welding, brazing and cutting
II - Arc Welding
III - Resistance welding
IV - Special Welding Processes
- Testing, measurements and control of welds VI - Terminology
*VII - Standardization and Documentation VIII - Hygiene and safety
*IX - Behavior of metals subjected to welding - Residual stresses and stress relieving XI - Pressure vessels, boilers and pipelines
XII - Flux and gas shielded electrical welding processes *XIII - Fatigue testing
XIV - Welding instruction
*XV - Fundamentals of design and fabrication for welding XVI - Welding of plastics
Study Group 212 - Physics of the Welding Arc
The Chairman of the Ship Structure Committee and the Chairman of the Ship Structure Subcommittee are members of the American Council's Executive Committee.
Present officers of the American Council are: Dr. I. A. Oehier, Chairman
Rear Admiral D. B. Henderson, USCG, Vice Chairman Edward A. Fenton, Secretary-Treasurer
Ship Structure Subcommittee membership on this council is provided by the chairman and Secretary of the Ship Structure Subcommittee.
*Indicates commissions which are of particular .interest to the Ship Structure Subcommittee.
D D FORM
I JAN 4i 473
Security Classificaon
(Security claaaiflcation of title, body oi abstract and ¡ndexing annotation must be entered when the overall report la classified) 1. OPIGINATIN G ACTIVITY (Corporate aVthor)
Ship Structure Committee
2e. ROPORT SECURITY C L.ASSIFICATION
UNCLASSIFIED
2h GROUP 3. REPORT TITLE
Biennial Report of the Ship Structure Committee
4. DESCRIPTIVE NOTES (Type of report and inclusive dates)
Biennial Report, 1 June 1966 - 1 June 1968
5 AUTHOR(S) (Last name, first name, initial)
6. REPORT DATE
1 June 1968
7e. TOTAL. NO, OF FAGE5
25
7b. NO, OF REFS Sa. CONTRACT OR GRANT NO.
b. PNOJECT NO,
C.
d.
9e. ORIGINATORS REPORT NUMBER(S)
SSC-187
Sb. OTNER REPORT NO(S) (Any other numbers diet may be assigned this report)
10. AVA IL ABILITY/LIMITATION NOTICES
Distribution of this document is unlimited
11. SUPPLEMENTARY NOTES 12. SPONSORING MILITARY ACTIVITY
Naval Ship Engineering Center Department of the Navy
13. ABSTRACT
Biennial report of the Ship Structure Committee to the convening authority, the Department of Transportation, covering and summarizing the activities of the committee and its affiliated research groups for the period 1 June 1966 - 1 June 1968.
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