AMPTIAC is a DOD Information Analysis Center Adminis tered by the Defense Information Sys tems Agency, Defense Technical Information Center

Special Issue:

Ships Navy Experts Explainthe Newest Material &Structural Technologies

The issue you hold in your hands has been 14 months in themaking. It began with a simple idea: turn the spotlight on theage-old art of building ships. We wanted to show the excitingnew technologies that are offering novel materials for ship con-struction, changing the way ships are built, and indeed creatingone of the most fundamental shifts in Navy combatants sincesteel replaced wood.

This simple mission turnedout to be much more complex.The project underwent a num-ber of different iterations, butfinally settled in and cametogether. It has been a labor oflove for yours truly, for I reallydo believe that even though air-planes and tanks often grab thespotlight, Navy ships are still the most challenging structuraland materials engineering systems fielded in today’s military.Nothing has the complexity, impact, size, and sheer force of afighting vessel, nor can many things capture the imagination inquite the same way.

So here it is, finally, and I am thankful that it is done. Notjust because it is off my desk and I can get on to the next proj-ect, but we are proud because AMPTIAC has compiled some-thing that probably has not existed before: an overview of thenewest technologies being incorporated into structures andmaterials for use aboard Navy combatants. And the people pro-viding the perspective are the experts at the Office of NavalResearch, NSWC-Carderock, and the Naval Research Lab. Youwon’t find this level of detail, variety, and expert contentfocused on this subject anywhere else.

That all being said, there is one critical feature of this publi-cation that needs some attention: the DOD center behind it.Some of you out there have been reading this publication forseven years now. You undoubtedly remember about two yearsago when we shifted over to our current layout format and full

color reproduction. You also have probably noticed that we arepublishing these large special issues fairly often. It is all a partof our mission to bring you the most in-depth, focused, andtechnologically exciting coverage of Defense materials and pro-cessing advances available anywhere.

But the side effect of the more noticeable and attention-grabbing Quarterly, is thatAMPTIAC itself has lost someattention. The reality is that thecenter has grown with numer-ous projects, focused reports,and database efforts over thepast few years, but there aremany out there that may readthis publication and not evenknow that the center exists.

We want to put more emphasis on the other efforts AMPTIAC is involved in, and let our customers and potentialcustomers know that we are here for you. We help with ques-tions, assist in materials selection, and provide consultation ona variety of materials and processing-related issues. We havemore than 210,000 DOD technical reports in our library anddirect access to hundreds of thousands more throughout DOD,DOE, NASA, and other US Government agencies. We havedozens of focused reports tailored to specific technology areasand many more compiling vast amounts of data into hand-book-style resources.

The basic message here is to take note of this magazine, readit, and enjoy. But if you think AMPTIAC is just the Quarterly,Think Again.

Wade BabcockEditor-in-Chief

Editorial: There’s More to AMPTIAC

than the Quarterly

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INTRODUCTIONThe primary hull structure of a modern surface ship can providepractical solutions for a multitude of obstacles facing a commer-cial or combatant design. Acquisition cost, life cycle costs,detectability, survivability, speed, range and payload are all, poten-tially, important factors when selecting a platform to perform aspecific mission. For improved performance in many of theseareas, significant resources have been allocated for further devel-opment of structural technologies used in both primary and sec-ondary structural applications. Often these technological optionsincrease the cost and complexity of the structure, have limitedimpact on overall ship operational capabilities, and are, therefore,only utilized in very weight-critical locations and designs.

In the late 1980’s, the Structures and Composites Departmentat the Naval Surface Warfare Center, Carderock Division(NSWCCD) began assessing the feasibility of the AdvancedDouble Hull (ADH) concept with attributes that can signifi-cantly impact all the areas in the design space. The ADH con-cept consists of an inner and outer hull, connected by longitu-dinal web girders. The resulting cellular structureexhibits increased structural capacityunder typical seaway loads and the oppor-tunity for improved resistance to weaponseffects. The ADH concept is shown inFigure 1.

GENERAL BENEFITS OF THE ADHThe ADH structure is unidirectional; all of the shell and deckmaterial acts in the longitudinal (parallel to the long axis of theship) direction. The transverse (perpendicular to the long axis ofthe ship) frames (welded stiffeners) have been eliminated and thetransverse bulkheads provide the support for the longitudinalstructure. The elimination of transverse frames in an ADH con-figuration has a number of positive effects on hull girder costand performance.

First of all, the elimination of the transverse framing leads to ageometric simplicity that produces significant acquisition cost sav-ings. It contributes to an overall reduction in the number of pieceparts, substantially reducing labor costs associated with the cuttingand welding at longitudinal stiffener and transverse frame inter-sections. Figure 2 and Table 1 illustrate the potential piece-partreduction of a typical destroyer assembly. The geometric simplici-ty also lends itself to automated fabrication processes.

Further, the elimination of transverse frames and the smoothinterior surfaces of the ADH structure greatly facilitate the

installation of distributive systems,painting, and their associated costs. A visual comparison is provided inFigures 3 and 4 showing the relativecomplexities associated with the instal-lation of these systems on a convention-

ally framed combatant and an ADH com-batant, respectively.

The distributive systems added to anADH structure would not have to navigate through

and over transverse structure. In fact, a cost comparison wasconducted for electrical, HVAC, and piping systems in adestroyer. The analysis estimated that the use of an ADH configuration would result in a 17.5% labor hour savings in theelectrical craft, a 17.9% labor hour savings in the sheet metalcraft and a 23.6% labor hour savings in the piping craft. When combined with other material, labor, and yard costs,construction expense for an ADH destroyer can be reduced by$60 million when compared to a conventional ship.[1]

The AMPTIAC Quarterly, Volume 7, Number 3 5

Jeffrey E. Beach, Director Survivability, Structures, and Materials Directorate

Daniel D. Bruchmanand

Jerome P. Sikora, Branch Head Design Applications Branch

Carderock Division, Naval Surface Warfare CenterWest Bethesda, MD

Figure 1. Graphic Depiction of ADH Concept (Left) and TraditionalShip Construction (Right).

The AMPTIAC Quarterly, Volume 7, Number 36

Ultimately, cost is most often the metric that governs theselection of a ship platform. Before a new technology is adopt-ed into a platform’s design, significant acquisition and/or lifecycle cost reductions as compared to existing processes anddesigns must be demonstrated. Acquisition cost is easily quan-tified and readily demonstrated with the ADH concept.However, life cycle cost reduction potential can be difficult todemonstrate – particularly for a combatant. Life cycle costsencompass recurring expenses such as routine maintenance,painting, corrosion management, structural failures resultingfrom typical seaway or combatant operations, military andpolitical ramifications if a platform cannot complete a mission,and replacement costs if a ship is lost at sea. The ADH conceptoffers a unique solution that significantly reduces costs andrisks throughout the operational life of the ship.

The structural material comprising the transverse frames inconventional, grillage construction (utilizing both transverseand longitudinal welded stiffeners) is redistributed into theinner and outer hulls in an ADH configuration - increasing thehull girder section modulus. This lowers the primary, seaway-induced longitudinal bending stresses and increases the fatiguelife of the structure. The elimination of the transverse framesfurther increases the hull girder fatigue life by significantlyreducing the number of crack initiation sites at the intersectionsof longitudinal stiffeners and transverse frames.

The increased section modulus also gives the ship designerflexibility to isolate (both acoustically and from shock) internaldecks, because they no longer need to resist primary loadings.Similarly, ADH technology can be utilized to incorporate mod-ular design capabilities into a ship system. The inherent

Figure 2. Piece-parts Used In Framing a Conventional Destroyer Hull Section.

Number of Basic Structural Pieces

Item ConventionalADH VarianceDesign Design < - >

Collars 200 0 <200>

Chocks 120 0 <120>

Panel Stiffeners 40 0 <40>

Access 40 11 <29>Opening Rings

Chafing Rings 100 20 <80>

Deep 11 13 +2Longitudinal Girders

Intermediate 6 0 <6>Shell Longitudinals

Intermediate Inner6 0 <6>Bottom Longitudinals

Individual 50 0 <50>Floor Panels

Docking 10 10 –Keel Brackets

Deep Long'l Girder7 9 +2Panel Stiffeners

Total Basic 584 63 <521>

Table 1. Comparison of Piece-part Requirements in aConventional and ADH Destroyer Assembly.

Collar Plates

Flange & TangencyChocks

PanelStiffeners

Shell & InnerBottom

Longitudinals& Stringers

LongitudinalGirders

LongitudinalGirders

TransverseFloors

KeelBrackets

Panel Stiffeners

ChafingRings

CompensationRings

The AMPTIAC Quarterly, Volume 7, Number 3 7

strength of an ADH hull form can also allow for large openingsin deck structures, simplifying the removal and replacement ofobsolete systems.

STUDYING THE MECHANICS OF THE ADHOver the last several years substantial research into the ADHhas documented the structural characteristics and performanceof the concept under a variety of loading conditions. Thisresearch has primarily focused on the performance of a pris-matic ADH structure located in the mid-section of the ship(where the sides are roughly parallel). Research has includedinvestigations into the stress behavior of prismatic ADH struc-tures [2] (Figure 5) and their ultimate strength (Figure 6).

Ford, et. al. were able to use the finite element method inconjunction with rigid vinyl model tests to evaluate the stressbehavior of an ADH structure. It was shown that, for a givenADH geometry, the stress state of the structure could be pre-dicted using classical strength of material approaches. Furtherinvestigations were conducted to determine the collapsestrength of ADH cellular structures, and are pictured in Figure7.[3]

Devine tested a series of large 3-cell and 5-cell ADHcolumns to collapse under axial loading conditions. A signifi-cant amount of scatter was observed in the behavior of thecolumns, particularly in the columns with plates having a slen-derness ratio (length/thickness) typically used in ship con-struction. Devine showed that classical plate-buckling equa-tions that did not account for welding-induced residual stress-es were somewhat unconservative. There was a significantreduction in the column collapse strength resulting from thewelding-induced residual stresses, which must be accountedfor in the design process.

The Oil Pollution Act of 1990 was enacted following theExxon Valdez tragedy in 1989. This legislation requires newlybuilt tankers trading in US waters to be fitted with double hull struc-ture. It also set a schedule for phasing out single hull tankers cur-rently in service. Significant assets were, therefore, allocated in theADH program to evaluate and improve the grounding and strand-ing behavior of double hull configurations (Figure 8).[4, 5, 6, 7]

Rodd was able to demonstrate through a series of large-scalegrounding tests, that inner hull rupture occurred at the trans-verse frames of conventional grillage construction. Removal of

transverse frames in the ADH allowed the structure toabsorb substantially more energy before inner hull fail-

ure. Additional crash resistant features were alsodeveloped to further enhance the configuration’sdamage resistance.

In addition to the extensive research to deter-mine the structural characteristics and behavior of

ADH structures under conventional loading conditions, therehas also been substantial research to determine their behaviorunder combatant loading conditions. This included analysis ofexplosions above the waterline (called AIREX) and below (calledUNDEX) (Figure 9).

NSWC conducted an extensive numerical analysis of anADH cruiser subjected to an underwater explosion.[8] Resultsindicated that an ADH configuration was better at attenuating

Figure 3. Typical Structure-System Interface on Conventional Combatant.

Figure 4. Typical Structure-System Interface on an ADHCombatant.

Figure 5. Rigid Vinyl and Finite Element Analysisof Stress Behavior in ADH Structures.

Longitudinals (Typical)Machinery

Platform Plate & Beam

Web Frame

Pipe (C)

Pipe (B)

Longitudinal BHD PlatingPlate & Beam

Pipe (A)

Pipe (C)

Pipe (A)

Pipe (B)

AdvancedDouble Hull

SmoothHullInner

Plating

Smooth Cored DeckMachinery Platform

The AMPTIAC Quarterly, Volume 7, Number 38

shock on equipment by reducing accelerations and peak veloci-ties during the UNDEX event.

Research to date indicates that, compared to a conventionalgrillage type of structure, the ADH is generally stronger andmore damage resistant under the tested loading conditions, withlittle increase in weight. Both acquisition and life cycle costs arereduced in the ADH concept due to geometric simplification,piece-part reductions and the associated facilitation of paintingand the installation of distributive systems. Furthermore, if thespace between the hulls is properly utilized and the right materialsselected, the ADH concept offers the potential for significantreductions in IR, acoustic and magnetic signature levels. The exten-sive research to date has culminated in the development of guide-lines for ADH structure design.[9]

MANUFACTURING/MAINTENANCE ISSUES WITH THE ADH CONCEPTThere are significant manufacturing, maintenance and in-spection issues unique to the ADH hull form. These issuesgenerally revolve around the ability to gain access to the

interior cell spaces and are magnified for smaller ship classes as the separation between the inner and outer hulls is reducedfor weight and volumetric considerations. As the distancebetween the inner and outer hulls increases beyond about onemeter, more conventional construction, maintenance andinspection methods can be employed.

Conventional welding techniques can be used for all aspects ofADH construction until the inner shell region is welded to thelongitudinal web girders in a design with a hull separation lessthan one meter. Then, because of the limited access to the inte-rior space, other welding processes may be required. Theseprocesses may include automated welding techniques and can beaccomplished from either inside or outside the cellular structure.Laser welding, electron-beam welding, and friction-stir welding(please see accompanying article in this issue by DeLoach, et. al.)have all been investigated and are viable options. Most near-termapplications being considered could be effectively fabricatedusing manual or mechanized welding techniques.

Maintenance and inspection issues of the small interior cellu-lar structure have been investigated. Robotic technologies havebeen studied [10] and proven to be effective means of perform-ing inspections and routine maintenance, such as painting andminor repairs when necessary (see Figure 10).

Corrosion maintenance and repair costs of Navy combatantsare estimated to be at least $1.2 billion a year for approximate-ly 360 ships.[11] Material selection, coatings and manufactur-ing techniques must be carefully evaluated to minimize corro-sion. In an ADH combatant, the increased horizontal surfaceswhere water can accumulate and the generation of additionalmoisture caused by variation in temperature between the inner

Figure 7.Measuring theCollapseStrength ofADHStructures.

Figure 6. Test Articles for Ultimate Strength Analysis ofADH Structures.

The AMPTIAC Quarterly, Volume 7, Number 3 9

and outer cell walls can aggravate corrosion problems.[9]Several coatings were evaluated for ADH applications to helpminimize corrosion problems. In general, high build epoxieswere the most effective in both long- and short-term exposuretests [12] and often outperformed the standard Navy F150/151epoxy system. Pre-coating ADH structural components alsoproved effective in reducing coating costs.

STAINLESS STEELSBudget conditions mandate that ship construction costs bereduced in future combatant construction. Many technologiesand systems that would improve combatant performance are notconsidered because they increase acquisition costs, and theimplementation of stainless steels for hull construction is oneexample of this. Although preferable to ordinary steel construc-tion for many reasons, austenitic stainless steels and other non-magnetic, corrosion resistant materials are not often consideredin combatant designs because of acquisition cost constraints.

The ADH concept provides a practical solution to the com-batant need for a more survivable hull form. It offers a uniquegeometry and significant cost savings during construction andthe installation of distributive systems that enable the practicalimplementation of many multi-spectral ship signature reductionoptions. These options include the use of austenitic stainlesssteels, not only for their ability to reduce the magnetic signature,but also for their high resistance to Charpy impact and explosionbulge loading. Their high elongation before rupture can alsolower hull girder bending stresses acting on the hull during anUNDEX event, and significantly increase survivability in theseconditions.[13] In Table 2, the properties of commonly usedmagnetic shipbuilding steels are compared with select non-mag-netic stainless steels.

There are a number of reasons why the ADH concept is anideal platform to introduce non-magnetic stainless steels. Theestimated $60M savings for a 9,000 long-ton ADH combatantcan more than offset the added expense in material and fabrica-tion costs of a comparable stainless steel combatant. Further,because the ADH concept lends itself to automated weldingprocesses, fume controls mandated by the Occupational Safetyand Health Administration (OSHA) are less problematic. These

requirements were set forth to protect personnel from the fumesgenerated during the welding of non-magnetic steels and nickel-based alloys.[14] Finally, automatic and robotic welding opera-tions enabled by the ADH’s geometric simplifications can ensurea more consistent, high quality weld than possible with manualwelding techniques. This is doubly important when weldingnon-magnetic stainless steels, as the weld quality must beextremely high in both weld surface condition and the welddeposit itself.[15]

To identify the costs and benefits of a stainless steel ADHcombatant, a comprehensive research and development pro-gram began in the late 1990’s. In this program, several stainlesssteels were evaluated based on the following criteria: weldabili-ty, welded properties, yield strength, elongation, residual stresseffects, fabrication distortions and crevice and stress corrosionsusceptibility. The materials also had to be non-magnetic. Basedon the selection criteria, the focus of the study centered onaustenitic stainless steels because, although the high nickel andchromium content makes the alloys expensive, they exhibit

Figure 8. Studying the Grounding Response of ADHStructures.

Figure 9. ADH Structures in UNDEX and AIREX Tests.

excellent ductility, formability and superior corrosion resistance.Austenitic stainless steels evaluated include AL-6XN, Nitronic50, and the 300 series. The material costs for plating ranged from$1.90/lb for the 300 series, $3.10/lb for the Nitronic 50, to$4.00/lb for AL-6XN.

Based on the results from the stainless steel research and devel-opment program, several performance and cost characteristicswere identified. Of the metals investigated, the 300 series steelswere particularly susceptible to crevice corrosion. In general, theAL-6XN provided the best corrosion protection and is recom-mended for the most corrosion-sensitive locations. Both the AL-6XN and the Nitronic 50 exhibited yield stresses comparable toAH 36. The 316L had a yield stress value around 30 ksi.

The stainless steel ADH hull form exhibited excellent multi-spectral signature control characteristics. The magnetic signa-ture alone was an order of magnitude less than that of an ordi-nary steel hull. However, this did require special handling andcutting techniques akin to those used for other non-magneticmetals such as aluminum. The space between the hulls couldalso be designed to significantly reduce the IR signature as wellby the inclusion of active or passive insulators.

CONCLUSIONS AND REMAINING CHALLENGESThe Advanced Double Hull concept can significantlyreduce both acquisition and life cycle costs. The cellularstructure exhibits increased structural capacity undertypical seaway loads, superior fatigue performance, andthe opportunity for improved resistance to weaponseffects. The inherent strength of an ADH hull form alsooffers the opportunity to isolate internal decks acousti-cally and from shock, providing a less detectable, moresurvivable hull. Further, the ADH concept is an idealplatform to construct out of stainless steels, thus provid-

ing the opportunity for multi-spectral signature control.Several issues however, remain to be investigated. ADH tech-

nology can’t efficiently be implemented approaching the bowwhere the hull form rapidly changes and exhibits flare. Thereforeoptimum details need to be identified in the regions where theADH structure transitions to a conventional structure. Work hasbegun to evaluate the performance of non-prismatic ADH struc-tures, but further research is necessary. When constructing a non-magnetic, stainless steel ADH, a dedicated yard with special tool-ing may be necessary. Additionally, there are higher levels of dis-tortion resulting from the welding process of the austenitic stain-less steels and flame straightening may be required.

REFERENCES[1] J. Beach. “Evaluation of Advanced Double Hull (ADH)Including the Use of Stainless Steels”, Presentation to SC-21Program Office, April 1997[2] H. Ford, J.M. Grassman, and R. Michaelson. “StressBehavior of Advanced Double Hull Structures”, Paper No. 10.Proceedings of the Advanced Double Hull TechnicalSymposium, 25-26 Oct, 1994, at Gaithersburg, MD[3] E. Devine, J. Ricles and R. Dexter. “Instability and CollapseStrength of Advanced Double Hull Structures”, Proceedings of theAdvanced Double Hull Technical Symposium, Paper No. 6,Gaithersburg, MD, 25-26 Oct, 1997[4] J. Rodd, with M. Phillips and E. Anderson. “StrandingExperiments on Double Hull Tanker Structures”, Proceedings ofthe Advanced Double Hull Technical Symposium, Paper No. 2,Gaithersburg, MD, 25-26 Oct, 1994[5] J. Rodd. “Frame Design Effects in the Rupture of Oil TanksDuring Grounding Accidents”, DERA, Proceedings of theInternational Conference - Advances in Marine Structures III,

Table 2. Material Property Comparison of Commonly Used Shipbuilding Steel and Select Non-magnetic Stainless Steels.

Ultimate Yield Elongation Charpy Modulus DensityMaterial Alloy Strength (ksi) Stress (ksi) (% in 2-in.) Toughness (ft-lb) (x10

6psi) (lb/in

3)

Shipbuilding AH36/ 71-90 51 22 17 transverse 30.0 0.283Magnetic DH36 25 longitudinal

Steel (20 °F DH36)(0 °F AH36)

Non- Nitronic 50 104 57 60 103-110 (75 °F) Magnetic 83-88 (-100 °F) 26.2 0.285

Steel AL-6XN 108 53 47 140 (70 °F)100 (-200 °F) 28.3 0.291

The AMPTIAC Quarterly, Volume 7, Number 310

Figure 10. Robotic Maintenance and Inspection of ADHStructures.

The AMPTIAC Quarterly, Volume 7, Number 3 11

Dunfermline UK, 20-23 May, 1997[6] T. Wierzbicki, E. Rady, D. Peer and J.G. Shin. DamageEstimates in High Energy Grounding of Ships, MassachusettsInstitute of Technology, Department of Ocean Engineering,Tanker Safety Program, Report No. 1, June 1990[7] T. Wierzbicki, D. Peer and E. Rady. The Anatomy of TankerGrounding, Massachusetts Institute of Technology, Departmentof Ocean Engineering, Tanker Safety Program, Report No. 2,May 1991[8] H. Gray. “Survivability Implications of Advanced DoubleHull Combatants”, Proceedings of the Advanced Double HullTechnical Symposium, Paper No. 18, Gaithersburg, MD, 25-26Oct, 1994[9] J. Sikora, and E. Devine. Guidelines for the Design ofAdvanced Double Hull Vessels, NSWCCD-65-TR-2001/04,West Bethesda, MD: Naval Surface Warfare Center, CarderockDivision, 2001[10] M. Gallagher, T. Barbera, and M. Bankard. “Inspection andMaintenance of Advanced Double Hull Cells”, Paper No. 17.Proceedings of the Advanced Double Hull Technical

Symposium, 25-26 Oct. 1994, at Gaithersburg, MD. 1994[11] D.D. Thurston. Recurring Fleet Corrosion Issues. Paperread at CORROSION 97 (NACE International) GroupCommittee T-9B (CINCLANTFLT maintenance TechnicalAdvisor), at New Orleans, LA, March 1997[12] H. Hack, Holder, A., Clayton, N., Dobias, P., Arazy, C.,Bowles, C., Brush, N., Vasanth, K., Katilaus, J., and JeanMontemarano. “Corrosion Control of Advanced Double HullCombatants”, Proceedings of the Advanced Double HullTechnical Symposium, Paper No. 16, Gaithersburg, MD, 25-26 Oct, 1994[13] E. Moyer, M. Pakstys, and C. Milam. “The Effects ofPlasticity on the Whipping Response of Surface Ships andSubmarines”, Proceedings of the 62nd Shock and VibrationSymposium, Vol. II, Springfield, Virginia, 29-31 Oct, 1991[14] National Shipbuilding Research Program. “Impact ofRecent and Anticipated Changes in Airborne Emission ExposureLimits on Shipyard Workers”, Report NSRP0463 (March 1996)[15] Marine Engineers Review. “Corrosion Resistance ofStainless Steels for Chemical Tankers”, March 1972

Dr. Jeffrey E. Beach is Director of the Survivability, Structures, and Materials Directorate at the Carderock Division,Naval Surface Warfare Center where he has been employed since 1969. He earned B.S. and M.S. degrees in aero-space engineering from the University of Maryland and has had additional graduate training in naval architecture andstructural engineering. He earned his doctorate in engineering management at The George Washington University.Dr. Beach manages a diverse program of exploratory, advanced, and engineering development research aimed atthe advancement and application of materials and structures to marine vehicle systems. He is active nationally andinternationally in professional societies, organizations, and exchanges, and has published and presented numeroustechnical papers in the international community. Among his awards are the 1984 American Society of NavalEngineers Solberg Award for research and the 1998 ASNE Gold Medal Award.

Daniel D. Bruchman has been employed at the Naval Surface Warfare Center, Carderock Division since 1986 whenhe received a BS degree in Civil Engineering from the University of Mississippi. Currently, he is a Naval Architect inthe Structures and Composites Department at Carderock, responsible for the technical analysis and evaluation ofadvanced structural systems under consideration for Navy surface ships and submarines. Mr. Bruchman began hiscareer specializing in the use of numerical methods to analyze conventional and unconventional hull forms. His designof a ship collapse facility, capable of testing large scale ship structures to collapse under pure moment or moment-shear combinations, has contributed to a much greater understanding of the global collapse of vessels under theseconditions. Recently, he has been involved in the development of high strength/lightweight materials and structural sys-tems for high speed ships while also serving as the Advanced Double Hull program coordinator.

Jerome P. Sikora has been employed at the Naval Surface Warfare Center, Carderock Division since 1969 when hereceived a BS degree in Physics from the University of Detroit. Currently, he is the head of the twenty-member DesignApplications Branch within the Structures and Composites Department, a position he has held since 1986. The DesignApplications Branch is responsible for developing structural design criteria and design tools for Navy surface shipsand submarines. Mr. Sikora began his career specializing in the field of static and dynamic optical measurements ofsuch structural parameters as stress, deformations, and vibration modes. He has been instrumental in the developmentof unconventional vessels and offshore structures such as SWATHS, tri-hulled ships, and the mobile offshore base. Overthe past two decades, he has developed probability-based loads criteria for conventional and SWATH ships.Recently, he has been involved in developing structural design criteria and design methods for the cellular structure ofthe Advanced Double Hull.