Design, Manufacturing, And Testing of WT Doors

Design, Manufacturing, and Testingof an Improved Watertight Door forSurface Ships& Stephen M. Copley, Edward W. Reutzel, Terri A. Merdes, and Dennis B. Wess

AbstractDesigned in the 1950s to be watertight during flooding and airtight under normal operating condi-

tions, the Navy standard watertight door for surface ships is inexpensive to manufacture but

expensive to properly install and maintain. Furthermore, by today’s requirements, it is too heavy.

The need for a lightweight, affordable, low maintenance watertight door led to a collaborative pro-

ject involving the Applied Research Laboratory at Penn State University, Naval Surface Warfare

Center, Carderock Division, Ship Systems Engineering Station, and Northrop Grumman Corpora-tion Newport News to design, fabricate, and test an improved watertight door for surface ships. The

design and manufacturing of this door is entirely new and based on advances in laser cutting and

welding technology. Its novel design reduces the number of dogs (latches) and linkages of the Navy

standard watertight door, decreasing the weight of the complete door assembly from 290 to 213 lbs.

The door is fabricated from corrosion resistant stainless steel, and its opening and closing forces are

extremely low, reducing the potential for mechanical and gasket wear. Pending successful comple-

tion of certification testing and with technical warrant holder approval, the new door will offer an

attractive choice for insertion by Acquisition Program Managers and Fleet Maintenance Managers.

IntroductionNavy watertight doors, hatches, and scuttles

(commonly referred to as watertight closures)

play a critical role in surface ship damage con-

trol. The current Navy standard quick acting

watertight door (NSWTD) was developed from

designs dating back to the 1950s or earlier.

Common watertight door sizes and configura-

tions are shared across most classes of surface

ships. Approximately, 32,000 NSWTDs are

currently in-service aboard combatants and

amphibs across the fleet (Burton and Simunov

2006). NSWTDs perform marginally in-service

and are very expensive to maintain. Marginal

performance is the result of obsolete design, ma-

terials susceptible to corrosion and wear, and

defects introduced during door manufacturing

and shipboard installation.

An initial needs assessment for the new water-

tight door led to requirements for:

&hydrostatic integrity

& shock resistance

& vibration resistance

& fire performance

&weight reduction

& acceptable procurement and installation cost

& significantly reduced maintenance cost

& reduced total ownership cost

& a domestic manufacturing base assuring a

competitive environment

T E C H N I C A L P A P E R

& 2011, American Society of Naval Engineers

DOI: 10.1111/j.1559-3584.2010.00282.x

2010 #4&93

These requirements will be further elucidated in

subsequent sections. From the outset, it was

clear that the design should focus on a single

watertight door configuration meeting specified

size and pressure requirements. Of particular in-

terest were the possibilities of applying the

accuracy and high speed of automated laser cut-

ting and welding in manufacturing the panel and

frame, and also developing a hydraulically

(water pressure) actuated seal system.

WatertightDoor SelectionInitially, the intent was to develop a design and

manufacturing methodology that would apply

to all sizes and configurations of watertight clo-

sures; however, it soon became obvious that this

scope was too broad to be accomplished with the

available resources. It was decided to select a

single watertight door configuration and, after

the design and manufacturing methodology had

been established on this door, to extend the

principles to other door sizes and configurations.

After consultation with the NAVSEA technical

warrant holder for ship hull outfitting systems,

engineering colleagues at the Naval Surface

Warfare Center Carderock Division, Ship Sys-

tems Engineering Station, Philadelphia

(NSWCCD), and Northrop Grumman Corpora-

tion Newport News (NGCNN), it was decided

to attempt to design a replacement for the 26 in.

�66 in., quick acting, 10 psi NSWTD with a

6 in. light (window). The 26�66 NSWTD con-

figuration is the most widely used configuration

in aircraft carriers and ships across the fleet. A

quick acting door is one in which the dogs are

simultaneously operated by a single handle

through a series of linkages. The door configu-

ration selected for replacement has eight dogs

(latches) and two hinges. The weight of the

10 psi NSWTD is 290 lbs (including door panel,

frame, and associated hardware). Interior and

exterior view assembly drawings of this water-

tight door are shown in Figure 1.

&The NSWTD’s marginal performance is re-

lated to several design features: the NSWTD is

made mostly of low carbon steel. It must be

painted or powder coated and the painted

surface must be constantly maintained to

avoid rust.

&The NSWTD is sealed by forcing a knife edge

against a silicone rubber gasket as illustrated

in Figure 2. The NSWTD must maintain its

seal for water loading both on the interior and

exterior sides. While loading on the exterior

side of the panel forces the gasket against the

knife edge, loading on the interior side forces

it away from the gasket. This must be resisted

by force applied by the dogs to the wedges in

order to maintain contact between the knife

edge and the gasket. These forces are large,

and sources of mechanical wear. Also, to

properly seat the knife edge on the gasket and

avoid pinching it on the hinge side, a ‘‘yoking’’

hinge is required.

&The lap-welded bulkhead installation concept

for the NSWTD frame assembly can introduce

distortion into the NSWTD door frame, re-

sulting in high mechanical operating forces

that frequently result in cascading secondary

component failures.

As shown in Figure 3, the frame is attached to the

bulkhead by two lap welds requiring contact be-

tween the frame and the bulkhead; however,

bulkheads are typically not flat. As a conse-

quence, the knife edge may become wavy due to

conformance with the existing bulkhead surface.

Adjustment of the hinges and dogging mecha-

nism during installation and frequent inspection

and adjustment in-service are required to ensure

that the knife edge maintains proper contact

with the gasket.

Initial Design Strategies forNewDoorOn a stiffness per pound basis, reinforcing the

panel sheet by welding angle irons on one side,

cupping the rims, and indenting the sheet is not

very efficient. Square or rectangular honeycomb

panels, with the spacing and thickness of the face

sheets properly sized, are more efficient in bend-

ing or uniform pressure loading because in cross-

section they place the bulk of material at a

greater distance from the neutral axis increasing

the second moment of inertia. Honeycomb panel

structures bonded by adhesives are often used in

NAVAL ENGINEERS JOURNAL94 &2010 #4

Design, Manufacturing, and Testing of an Improved Watertight Door

lightweight structures. Metallic honeycomb

panels have been produced by brazing metallic

alloy face sheets to the honeycomb. Using brazes

to join metallic stiffeners to face sheets for use in

a sea environment is undesirable: the chemical

dissimilarity of the braze alloys to the metallic

honeycomb panel creates a high risk of galvanic

corrosion.

It was recognized early in this project that laser

welding and cutting could potentially provide an

entirely new approach for fabricating metallic

alloy honeycomb panels and frames for the new

watertight door. Laser cutting is fast and very

accurate. Face sheets could be autogenously

welded to the honeycomb, i.e., welded without

filler metal, at high speeds. Laser cut and welded

panels could be fabricated from stainless steel

greatly reducing the risk of corrosion. A number

of domestic, commercial job shops were identi-

fied that were capable of laser cutting and

welding the new watertight door. The applica-

tion of laser technology to the manufacturing of

stainless steel watertight doors was identified as

an important design strategy for the new door.

Figure 2: Dog De-tail (NAVSEA 1987)

Figure 1: Navy Standard Watertight Door (26 in. �66 in., Quick Acting, 10 psi Door with Window): (a) Interior Side and (b) Exterior Side (NAVSEA 1987)

NAVAL ENGINEERS JOURNAL 2010 #4&95

A second important design strategy was to re-

place the dogs, wedges, knife edge, and

compression gasket seal system of the NSWTD

with a novel hydraulically actuated seal system.

The initial concept is illustrated in Figure 4.

Flooding the door on one side forces the hollow

cylindrical gasket against the gap on the other

side plugging it and vice versa. Unfortunately,

this simple concept did not work due to the large

dimensional changes in the gasket cavity when

the door was loaded. Also, lab testing of early

prototypes of the hollow oval seal configuration

revealed that unacceptably high compressive

forces were required to initially seat the seal to

ensure watertight performance. This finding

clarified the desirability of a seal design that did

not require high initial compressive forces. In the

end, the development of a hydraulically actu-

ated, leak-free seal system became the most

challenging design aspect of the project.

Also illustrated in Figure 4 is the third important

design strategy, which will be referred to as the

plug-in-hole frame. This strategy eliminates the

influence of bulkhead waviness on the seal sys-

tem. The plug-in-hole frame is designed to slide

inside the hole cut in the bulkhead. It is attached

to the bulkhead by two fillet welds. This im-

proves upon the NSWTD design in which the

frame is clamped and lap welded to the bulk-

head. Lap welding the frame to the bulkhead

causes the frame to conform to any ‘‘waviness’’

or ‘‘out-of-plane’’ condition of the existing

bulkhead.

In what follows, each of these strategies will be

discussed in greater detail.

LASER CUT AND WELDED DOOR PANEL AND

FRAME

At the heart of the new watertight door design is

a laser cut and welded panel structure called

LASCELL (patent pending). It can be described

as a rectangular (including square) honeycomb

of laser cut metallic stiffeners, mechanically in-

terlocked, joined to laser cut face sheets by

autogenous welds through the face sheets into

the stiffeners, as illustrated in Figures 5 and 7.

It soon became clear that cutting the stiffeners

and face sheets with a laser was straightforward

whereas welding such a structure was to be a

challenge. Although it was possible to spot weld

the face sheets to the stiffeners without distor-

tion, even one continuous weld of face sheet to

stiffener caused the panel to bend in fabrication

of early prototypes. Multiple parallel continuous

welds caused the panel to form a cylindrical

shape with the cylinder axis lying parallel to the

welds.

The origin of the observed distortion can be ex-

plained as follows. When the face sheet was

welded to the stiffener, the alloy melted locally

and then resolidified as the laser beam moved

past. As it resolidified, very hot melt at the weld

was surrounded by unmelted solid that was

much cooler because of the high speed of the la-

ser beam. The resolidified melt, which was much

hotter than the surrounding solid, shrank more

due to thermal contraction upon cooling, result-

FRAMEWITHKNIFEEDGEPANEL

BULKHEADLAP WELDSGASKET

Figure 3: Edge Sec-tion of NSWTD SealSystem Showing theFrame Lap Welded tothe Bulkhead with ItsKnife Edge Contactingthe Gasket

PANEL

FRAME BULKHEAD

FILLET WELDS

GASKETFigure 4: Hydrauli-cally Actuated Sealand Plug-In-Hole In-stallation Concepts

NAVAL ENGINEERS JOURNAL96 & 2010 #4


ing in plastic deformation that caused the ob-

served distortion.

To fabricate the first LASCELL panel structure,

the following procedure was developed. Laser

cut stiffeners were assembled using a position

fixture (an aluminum plate with an orthogonal

grid of milled slots) to form the mechanically in-

terlocked rectangular honeycomb. A face sheet

was placed on the stiffeners and held in place by

restraining bars, see Figure 6.

Laser spot welds, one inch apart, were made

through the face sheet joining it to a parallel set

of stiffeners. The structure was then rotated by

901 about an axis perpendicular to the face

sheet, and a similar set of spot welds was made

joining the face sheet to the second parallel set of

stiffeners, which were perpendicular to the first

set. The panel was then removed from the posi-

tioning fixture, turned over, and the process was

repeated. In both the spot welding and the con-

tinuous welding steps to follow, welding started

at the innermost stiffener(s) and progressed to-

ward the face edges. No distortion of the panel

was observed after spot welding the face sheets

to the stiffeners.

With the spot-welded panel restrained by the re-

straining bars as illustrated in Figure 6, one face

sheet was then continuously autogenously laser

welded to a parallel set of stiffeners. After this

step, the panel was released from the restraining

bars. When the bars were removed, the tension

stresses in the face sheet were partially relaxed

by the distortion; however, this distortion caused

residual tension stresses to develop in the face

sheet on the opposite side of the panel.

In order to make a flat structure, the panel was

then turned over and elastically deformed by the

fixtures so that it was again completely flat. It

was then continuously laser welded to the same

set of stiffeners on their opposite edge. Flatten-

ing the panel was critical. If the panel was not

completely flat before the face sheet on the op-

posite side of the panel was welded, the residual

stresses introduced by continuously welding the

first side would not be balanced by the residual

stresses resulting from welding the second side,

and the panel would still be distorted to an un-

acceptable degree.

The panel was then rotated 901 in the x–y plane

(see Figure 5), restrained by the fixtures, and the

continuous welding process was repeated on op-

posite sides. If welding was carried out in

accordance with this procedure, it was found

that a completely flat panel was produced.

Figure 7 shows a stainless steel 1 ft�1 ft square

LASCELL panel (Alloy 316). The stiffeners were

cut with a carbon dioxide laser from sheet

0.120 in. thick at a speed of 50 in./min using

2000 W beam power. A high-velocity N2 gas jet

y

x

Figure 5: LASCELLStructure

Figure 6: Position-ing Fixture andRestraining Bars


was focused concentric to the beam to aid mate-

rial removal. The face sheets were laser cut from

sheet 0.036 in. thick.

For the laser welding, a helium cover gas was

used to suppress plasma formation. At a speed of

130 in./min and 2000 W beam power, it was

found that a weld�0.035 in. wide was formed at

the interface where the stiffener edge was joined

to the face sheet.

In developing the process to fabricate LASCELL

panels, an important and unanticipated feature

of the laser-welded panels was discovered that

differentiates them from honeycomb panels

formed by other methods. If fabricated in accor-

dance with the preceding description, these

panels were prestressed so as to increase their

resistance to the usual honeycomb panel failure

mode, localized plastic face sheet buckling. Dis-

cussion of the mechanics and properties of these

panels is beyond the scope of this paper, but has

been presented elsewhere (Copley et al. 2005;

Copley et al. 2006).

Adaptation of the LASCELL panel structure to

the watertight door was first accomplished by

fabricating a one-half scale door. In this case, re-

straining bars were used and a procedure similar

to that described for fabricating the 1 ft�1 ft

square panel was followed. In fabricating, a full

size door, it was found however that the re-

straining bars flexed and were not sufficiently

stiff to flatten the panel after the initial continu-

ous laser welding step.

A new procedure was devised involving the en-

casement of the door in a massive aluminum

fixture with slots to allow passage of the laser

beam. This approach was used to fabricate the

first full size watertight door of the new design at

ARL Penn State, and was used as the basis for a

bid package distributed to 10 potential manu-

facturers deemed capable of manufacturing the

new door. Five of these responded to the request

for quote with formal proposals. The two lowest

bids were selected, and the winners manufac-

tured the first set of 10 doors. They were

Begneaud Manufacturing Inc., Lafayette, LA,

and MDL Manufacturing Industries Inc., with

plants in Bedford, PA and White Plains, MD.

The first 10 doors that were fabricated were used

for development of the seal system, for a trial

installation at NGCNN, for precertification

shock testing, and for display.

Handling the massive aluminum fixtures used to

manufacture the first set of watertight doors

proved to be too time consuming and costly.

MDL was tasked to develop an automated pro-

Figure 7: StainlessSteel LASCELL Panel(Inset Shows Autoge-nous Weld, WhiteDots Added to Em-phasize WeldBoundary)

Figure 8: New Wa-tertight Door withStrong Backs (Arrows)Used to RestrainFrame during Weld-ing to Bulkhead



cess for laser welding the watertight doors. They

developed such a process to manufacture doors

for precertification hydrostatic testing, certifica-

tion testing, and for two in-service shipboard

evaluations.

PLUG-IN-HOLE FRAME INSTALLATION

Figure 8 shows three aluminum installation fix-

tures (strong backs) developed by NSWCCD to

restrain the panel of the door during welding of

the plug-in-hole frame to a bulkhead. This pho-

tograph was taken at Aeronav Test Labs,

College Point, NY, before precertification shock

testing.

The strong backs were of great value during the

trial installation carried out by ARL Penn State

in collaboration with NGCNN and NSWCCD

at Newport News. During shipboard installa-

tion, the panel must be removed from the frame

to provide an escape path in the event of a fire.

While leaving a path for escape, the strong backs

provided sufficient restraint of the frame so that

distortion during welding to the bulkhead was

kept to an acceptable amount. Furthermore, the

strong backs provide a means of attaching a

hoist to lift the door into place during installa-

tion. The trial installation at NGCNN suggested

a number of design improvements to facilitate

shipboard installation, a full discussion of which

is beyond the scope of this paper.

HYDRAULICALLY ACTUATED SEAL SYSTEM

The hydraulically actuated seal system proved to

be the greatest challenge of the new watertight

door design. The final design concept is illus-

trated in Figure 9.

In Figure 9, the gasket (green) is shown in the

closed door position. It is installed by snapping it

into place between the containment rods that are

tack welded to the panel rim as illustrated in

Figure 10.

If the door is flooded from the interior side, wa-

ter presses the interior maxi-wiper against the

frame rim thus blocking flow. The interior con-

tainment rod is spot welded to the panel rim so

water can seep between the rod and the rim and

may seep under the interior containment tab.

The purpose of the interior mini-wiper is to

block such flow. On the other hand, if the door is

flooded from the exterior side, water is blocked

by the exterior maxi-wiper pressing against the

frame rim. Flow seeping under the exterior con-

tainment rod and containment tab is blocked by

the exterior mini-wiper.

The purpose of cavities within the gasket is to

balance flow during the extrusion manufactur-

ing process so that flow through the central

region of the gasket does not advance too far

beyond flow in the narrow wipers.

Current StatusMuch interesting detail regarding the evolution

of the design of the new watertight door has

been omitted here in the interest of brevity. The

following summarizes the current status.

Exterior Side Mini-WiperExterior Containment Tab

Exterior Containment RodExterior Maxi-Wiper

Interior Mini-WiperInterior Containment TabInterior Containment Rod

Interior Maxi-Wiper

Frame Rim

Tack Weld

Tack Weld

INTERIOR SIDE

EXTERIOR SIDE (SIDE WITH HINGES AND LATCHES)

Panel Rim

Figure 9: Hydrauli-cally Actuated SealSystem

PanelRim

InteriorContainmentRod

ExteriorContainmentRod

Gasket

ExteriorMaxi-Wiper

Figure 10: The Gas-ket Was Installed byInsertion between theContainment Rods


WATERTIGHT DOOR DESIGN

The stiffener arrangement in the panel and frame

of the new door is illustrated in Figure 11. Exten-

sive finite-element analyses were carried out to

ensure the structural integrity of the watertight

door. They resulted in increasing the stiffener

height to 1.3 in. and the face sheet thickness to

0.048 in. to increase stiffness and strength. A

compensating weight reduction was achieved by

laser cutting holes centered on the neutral axis of

the stiffeners.

The new watertight door was hydrostatically

loaded multiple times during prototype lab test-

ing to 15 psi pressure, an overload of 50%,

without permanent deformation, mechanical

failure, or any loss of functionality.

The new watertight door weighed assembly in-

cluding frame 213 lbs, a 27% reduction

compared with the 26 in. �66 in., 10 psi

NSWTD.

SEAL SYSTEM

Leakage at low rates (�1–10 mL/min) was not

difficult to achieve with the hydraulically actu-

ated seal system, but the Navy requires zero

leakage at 10 psi design pressure. Although pre-

senting a great challenge, this requirement was

finally satisfied in laboratory testing. Important

issues contributing to this success included: con-

trolling the gasket length; forming a smooth

joint between the ends of the extrusion; uniform

positioning of the gasket in the corners of the

door; and smoothness of the gasket cavity. ARL

Penn State worked closely with its supplier,

Northwest Rubber Extruders, Beaverton, OR, to

address these issues.

A hydrostatic loading test matrix specified by

NSWCCD was successfully completed, includ-

ing: two frame/panel combinations from

different doors; two different gaskets; and two

loading directions (repeated three times) giving a

total of 23�3 5 24 successful tests. In each test,

the door was loaded to 10 psi and held for 20

minutes with no leaks whatsoever. The opening/

closing (pull/push on handle) force for the new

watertight door was o2 lbs.

MANUFACTURING

The automated manufacturing system developed

by MDL to manufacture the new watertight door

is shown in Figure 12. The door was attached to a

rotary stage after spot welding. Several welds

were made on one side and then the door was ro-

tated so that the thermal stresses and distortion

produced by these welds could be balanced by

making welds on the opposite side. This was con-

tinued in a specified weld sequence until the

welding assembly was completed. In Figure 12,

the door is shown in mid rotation with five con-

tinuous welds completed on one side.

The automated welding system has demon-

strated the capability of completing all

continuous autogenous laser welds, approxi-

mately 332 ft of welds, in 45 minutes. This

automation is critical to achieve the goal to re-

duce the procurement cost to US$4,500 per door

assembly.

Figure 11: NewWatertight DoorShowing Holes inStiffeners along theNeutral Axis BeforeSpot Welding theFace Sheet to theStiffeners

Figure 12: Auto-mated WeldingSystem Developed byMDL under Subcon-tract to ARL PennState



TESTING

The new door design has undergone extensive

precertification testing, and actual US Navy

Certification tests are just beginning. Perhaps the

most critical certification test is the Grade A

shock test in accordance with MIL-S-901D that

specifies that the door be hydrostatically tested

to design tightness pressure and function at the

end of three shock blows. The test is conducted

in three door orientations: (a) door upright; (b)

door rotated 451 in plane of the panel; and (c)

door rotated 451 out of plane. The latter orien-

tation is shown in Figure 13.

The door sits on a platform that is impacted on

the underside by a heavy swinging pendulum

hammer. The handle of the door was shortened

for the test to balance the door latching mecha-

nism and eliminate the opening moment. Later,

this adjustment was incorporated into the design

by replacing the stainless steel handle with a light-

weight fiber reinforced composite handle and

rubber cap. The new watertight door survived

the shocks without structural damage; however,

the hydrostatic testing was omitted during pre-

certification testing because the seal system had

not been perfected at the time of the test.

As previously mentioned the new watertight

door underwent numerous hydrostatic tests as

part of the door and seal development and in

completing NSWCCD’s test matrix. The test

tank arrangement is shown in Figure 14. The

frame was welded to a 0.5 in. mock bulkhead.

The bulkhead was bolted to the tank and sealed

with an expandable tape gasket. Water was sup-

plied to the tank through an inlet pipe visible on

the right hand side of the tank. Pressure at the

bottom of the tank was measured with the pres-

sure gage.

One of the doors was successfully hydrostatic-

ally tested to 10 psi without leakage as the first

step in the hydro/million cycle open–close,

latch–unlatch/hydro reliability test required for

US Navy certification. It has been delivered to

NSWCCD for the cyclic testing, and is to be fol-

lowed by postcyclic hydrostatic testing.

CERTIFICATION TESTING

NSWCCD has taken the lead in arranging and

conducting certification tests in accordance with

the American Bureau of Shipping Naval Vessel

Rules Part 1, Chapter 5, Section 1, Paragraph

2.4. In addition to hydrostatic, shock and cyclic

tests, vibration, fire performance, EMI tests, and

in-service evaluations are required. Technical

Warrant Holder approval will be based on suc-

cessful completion of the certification tests and

on successful in-service evaluation described as

follows.

Figure 13: ShockTest of New Water-tight Door Rotated451 Out of Plane

Figure 14: NewWatertight DoorWelded to BulkheadThat Bolted to Hydro-Test Tank


IN-SERVICE EVALUATION

Two at-sea, in-service evaluations are planned

for initiation in FY 2010 and will require 1 year

to complete. Six additional at-sea, in-service

evaluations involving three platforms, two doors

each, are planned and are anticipated to be com-

pleted by early CY 2012. In these evaluations,

the doors will be retrofitted onto actual ships and

subjected to typical US Navy in-service use.

SummaryandConclusions

&A new watertight door based on laser cutting

and welding technology has been designed,

manufactured, and tested, offering reduced

weight and reduced total ownership cost

compared with the NSWTD.

&Novel features of the new door include its

LASCELL panel structure, plug-in-hole frame,

and hydraulically actuated seal system.

&Assuming success in all US Navy certification

testing and NAVSEA technical warrant holder

approval, this new door design will offer an

attractive choice for insertion by Acquisition

Program Managers and Fleet Maintenance

Managers.

AcknowledgmentsThe authors are grateful to their colleagues

James Burton, David Simunov, Ernesto DiSan-

dro, Kenneth DiFonzo, Constantine Pappas, and

John Tareila at the Naval Surface Warfare Cen-

ter Carderock Division—Ship Systems

Engineering Station, Philadelphia, and David

Rice and Anna Yurashus at Northrop Grumman

Corporation, Newport News, for their technical

contributions and interest. They would like to

thank the staff at the ARL Laser Processing Di-

vision Laboratory, especially Chris Sills for his

assistance in the early phases of the project, and

Richard Martukanitz for his role in identifying

the opportunity for laser technology to address

the need for an improved watertight door. They

would also like to thank Tim Bair, iMAST Di-

rector; and John Carney, Director; and Greg

Woods, Program Officer, of ONR ManTech as

well as Glen Sturtevant, Director of Science &

Technology, PEO Ships, and William Boulay,

American Systems Inc.; for their continuous in-

terest and support.

This material is based upon work supported by

the Office of Naval Research, through the Naval

Sea Systems Command under Contract no.

N00024-02-D-6604. Swampworks funding and

Technology Insertion Program for Savings fund-

ing are gratefully acknowledged.

Any opinions, findings, conclusions, or recom-

mendations expressed in these materials are

those of the authors and do not necessarily re-

flect views of the US Navy.

ReferencesBurton, J. and D. Simunov, ‘‘In-service surface ship wa-

tertight doors: analysis of options,’’ Presented to PEO

Ships F Program Reviews, Watertight Door Technical

Splinter Group, February 15, 2006.

Copley, S.M., E. Ventsel, and P. Vigna, ‘‘Laser fabricated

metallic cellular sandwich panels,’’ Proceedings of the

International Congress on Applications of Lasers and

Electro Optics, ICALEO’05, Miami, FL, November 3,

2005.

Copley, S.M., P. Vigna, and E. Ventsel, ‘‘Beneficial pre-

stress in laser fabricated, metallic, square, cellular

sandwich panels,’’ Proceedings of the International

Congress on Applications of Lasers and Electro Optics,

ICALEO’06, Scottsdale, AZ, October 30, 2006.

NAVSEA, NAVSEA STD DWG 803-2226372 Rev B, doors,

hatches, and scuttles—general notes, October 6, 1987.

AuthorBiographiesStephen M. Copley is the principal author. He is

Senior Scientist at the Applied Research Labo-

ratory, Materials and Manufacturing Office,

Laser Processing Division, and Professor of Me-

chanical Engineering, Penn State University. Dr.

Copley received his B.A. in Physics, M.S., and

Ph.D. in Engineering Science, all from the Uni-

versity of California at Berkeley. A technical

contributor to the laser materials processing

field since the 1970s, he is a Fellow of ASM

International and ASME; e-mail: smc21@

psu.edu.

NAVAL ENGINEERS JOURNAL102 &2010 #4


mailto:e-mail: [email protected]

mailto:e-mail: [email protected]

Edward W. (Ted) Reutzel is the Head of the Sys-

tem Engineering and Integration Department

within the Laser Processing Division at the

Applied Research Laboratory, Penn State Uni-

versity (ARL Penn State). He has 15 years of

experience in welding, modeling, sensing, con-

trol, and laser processing. Dr. Reutzel received

his B.S. in Mechanical Engineering from the

Georgia Institute of Technology and his Ph.D. in

Mechanical Engineering from Penn State

University.

Terri A. Merdes is a test engineer and finite-ele-

ment analyst in the Advanced Computational

Analysis and Design Department, Composite

Materials Division at the Applied Research

Laboratory, Penn State University. She received

her B.S. in Mechanical Engineering and her M.S.

in Quality Manufacturing and Management

from Penn State University.

Dennis B. Wess is a mechanical design and anal-

ysis engineer in the Process and Product

Development Division at the Applied Research

Laboratory, Penn State University. He received

his B.S. and M.S. in Mechanical Engineering

with a minor in Engineering Mechanics from

Penn State University.


Design, Manufacturing, And Testing of WT Doors

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Transcript of Design, Manufacturing, And Testing of WT Doors