Design and Optimization of Aluminum Structures for the 21st Century Navy

Dr. Brett ConnerSegment Leader, Sea Systems

Alcoa Defense

June 15, 2010

Agenda

Meeting Challenges with Alcoa’s Collaborative Development Approach (ACDA)

Aluminum Design Innovation Leadership

Aluminum Design Development Approach

Design Challenges for the 21st Century Navy

2

Aluminum: What’s your reference point?

3

Legacy Current FutureAlloy Primarily 5456 5456, 5083, some 6xxx (not really

new alloys). 5454 in elevated service temperature areas

New alloys?

Product forms Plate, extruded stiffeners Plate, specialty extrusions including multi-hollows

Legacy + Current + Advanced Hybrid Materials?

Construction: Manual labor intensive “stickbuilding”

Panelization through the use of automated linear welding

Advanced lightweight panels?

Joiningtechnology

GMAW or GTAW. Mostly manual

GMAW, GTAW, FSW, HDGMAW, etc. More automation.

Legacy + Current + Adhesives? + Advanced fastening? + Laser weld?

Marine plate specs

AMS-QQ-250 or ASTM B209 ASTM B928 TBD?

Design tools Hand calculations, empiricism, global stress analysis

legacy tools + FEA (more localized stress analysis), Spectra Fatigue Analysis

Multiscale modeling? Time-stepmodeling? Prognosis?

The shape of the future for aluminum in ship

design and construction will depend on innovative

material and design solutions between the

shipbuilder, naval architect, the Navy and

Alcoa

Alcoa Technical and Parental Advantage

Alcoa Innovations for the Designer

4

Audi A8 Challenge:Rebranding for uncompromising performance and luxury

Airbus A380 Challenge:Product expansion: develop and product the largest commercial airliner in the world

LM F-35 Challenge:Develop and product the next generation tactical fighter for USAF, USN, USMC and allies

Solution: The Audi Spaceframe• Material development• Product forms• Fastening• Design simplification

Solution: 7085 Wing Spar Forging• Product form• Parts reduction• Strength

Solutions: Bulkhead and Lift Fan Forgings, Eddie Bolt fasteners, Engine components• Product forms• Fastening• Strength

5

The Audi Story

94 95 96 97 98 99 00 01 02 03 04 05 06 07 08

Audi A81st Generation

Audi A8 — 2nd Gen.

Alcoa Spaceframe Technology 10 Year Strategic Development

Partnership Co-developed new design

methods & capabilities 40 New Patents 7 New Aircraft Grade Aluminum

Alloys New Casting & Manufacturing

Processes & Factory

Repositions Audi as luxury brand

Rated safest car in its class Received

rating from insurance company for repairs

Reduced component and assembly costs by 50%

Major parts consolidation with large castings

More interior space than predecessor

Faster than its predecessor

6

6

Alcoa Collaborative Development Approach (ACDA)- Collaborative IPT Teams (OEM, Alcoa, Military) -

Phase I -Identify and Select Candidate Assemblies/ComponentsPhase II -Develop and Evaluate Conceptual DesignsPhase III -Finalize Conceptual Designs and AnalysesPhase IV -Develop and Evaluate PrototypesPhase V -Implement Designs in Production

4thgate

3rdgate

2ndgate

1stgate

PartID

ConceptDesign Prototyping ProductionFinal

DesignI II III IV V

Opportunity identification

Gather geometry, packaging, load req’s

Develop concept redesign options

Prelim. evaluation of conceptual redesigns

Down-select concepts for further development

Ex. Activities: Finalize part redesigns –

detailed CAD and analysis

Evaluate advanced design concepts

Finalize total costs and plans for prototyping

Develop prototype part fabrication and test plans

Produce prototype parts

Test prototypes and approve for production

ACDA

7

Phase II: Develop and Evaluate Conceptual Designs

Gather geometry, packaging, load req’s

Develop concept redesign options

Prelim. evaluation of conceptual redesigns

Down-select concepts for further development

Customer evaluation criteria

Phase I: Identify and Select Candidate Structures

Opportunity Identification with OEM

• What are the challenges?• What are the pain points?

Materials Data &

Development

Structural Design

Manufacturing Tech

Advanced Power & Energy

Design Rules & Tools

SolutionIdeation

Phase III: Final Design Analysis

Finalize part redesigns –detailed CAD and analysis

Evaluate advanced design concepts

Finalize total costs and plans for prototyping

Component testing

Phase IV: Develop and Evaluate Prototypes

Develop prototype part fabrication and test plans

Produce prototype parts

Test prototypes and approve for production

Product ManufacturingProduct Design and Development

ACDA can be implemented during trade studies, concept development, contract design or even detailed design

Agenda

Meeting Challenges with Alcoa’s Collaborative Development Approach (ACDA)

Aluminum Design Innovation Leadership

Aluminum Design Development Approach

Design Challenges for the 21st Century Navy

8

9

Customer Requirements Addressed by Alcoa Designers

Light weighting of structures

Structural analysis and design Cost reduction

– Materials, design, manufacturing, assembly

Alloy selection/recommendations– Structural, thermal, electrical, corrosion,

forming, cost

Fractures/Failures– Joints: Mechanical, Adhesives, Fusion

Welds, FSW, LSW– Product forms (castings, extrusions, sheet,

Plate): yielding, fracture, buckling, wear, corrosion

Material and Manufacturing Quality– Wrought, welded, extruded, cast

Fabrication and assembly recommendations and implementation

Corrosion issues and environmental durability

Repair methods

Mechanical testing and material performance

Prototype product manufacture

Surface management

No one knows aluminum structural design better than Alcoa

10

Alcoa Design Technologies

Alcoa’s design technologies have been successfully leveraged across multiple commercial and defense market segments– Passenger and bulk hauling rail cars– Transportation systems such as bulk trailers and intermodal

containers– Cars, trucks and busses– Commercial aerospace– Defense aerospace, sea and land systems

Design activities are driven by customer performance requirements and standards– Alcoa has found that its design competencies and toolkits are fully

transferable to other market segments once we learn a customer’s performance requirements and standards

11

Rail Car Design and Analysis Expertise

Cars made of 5XXX alloys

Designing to AAR (American Association of Rail Roads) standards– Static structural analysis– Dead load, live load, draft

load, buff load, compression end load, impact load

Shaker test simulation

Dynamic squeeze test simulation

Thermal buckling simulations

Manufacturing cost analysis/reduction

Alcoa has been building its rail car design and analysis expertise and

experience since early 1930s

12

Rail Car Design and Analysis Examples

Coal Car AAR Compressive End Loading

Lateral Deflection Von Mises Stress Plot

Coal Car Mode Frequency Analysis

Phase III: FEM Validates Concept - Confidence to go to Prototype

13

Transportation System Design and Analysis Expertise and Examples

Bulk Trailer Design Designing Intermodal Containers for ISO Standards

20ft Dry Tainer 40ft Dry Tainer

Internal Pressure Load Case

Deflections Stresses

14

Automotive Design and Analysis Expertise

15

Commercial Aerospace Design and Analysis Tools and Expertise

By working with customers, Alcoa’s rapid trade study tools and rapid testing help identify benefits of new materials and design concepts

Inboard stiffener view

2 - bay fatigue crack

exit skin crack

Outboard stiffener view

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0 1000 2000 3000 4000 5000 6000 7000

Number of Flights

Hal

fC

rack

Len

gth

(inch

)

C47A - T8X

110% Load

C433 - T351

110% Load

MT Spec., W=7.8 inches, B=0.47 inchesRH > 90% Freq. = 10 Hz

C47A - T8X, 120% Load

C433 -T351

100% Load

2024 - T351

100% Load

7075 frame

16 in. spacing

2a

2524 - T3, or 2024 - T3 skin

• Fatigue crack grows due to

hoop pressurization stress

• Max cyclic stress ( σ max ) =

12 to 15 ksi , R = 0.1

• Initial damage 2ao = 2 in.

2

4

8

6

Hal

f cra

ck le

ngth

, a, (

in.)

0 84 12 16

No. flights (thousands)

2524 - T3

2024 - T3

σ max in

Ksi

13 12

15 14 13 12

0

Example: Predicted Longitudinal fuselage skin crack under intact frame

14

ASPAN-F Curved Panel Design SoftwareThe 2524-T3 toughness advantage considerably

increases the 2-bay crack residual strength

The 2524-T3 FCG advantage enables an operating stress

increase at lower weight, or longer periods between

inspections

Alcoa’s new materials show improvement in crack growth under lower wing spectrum

Residual strength and crack growth testing (integral panels shown)

root

tip

large

wing

root

tip

large

stabilizer

Load Intensities Typically found in

Upper Wing and Stabilizer Structure

root

tip

small

wing

large

fuselage

belly

large

fuselage

crown

Load IntensityCompression Design Stress Levels at Ultimate

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

3 5 7 9Stiffener Spacing (in.)

Max

imum

Allo

wab

le S

tres

s Le

vel a

t Ulti

mat

e (

psi)

7075 - T6xx

7150 - T61xx

7150 - T77xx

7055 - T77xx

5,000 lb/in.

2,000 lb/in.

10,000 lb/in.

15,000 lb/in.

35,000 lb/in

As load levels increase, Alcoa’s higher strength 7055 alloy shows

large weight savings potentialAlcoa Compression

Design Software

ASPAN-W Spar Design Software

[after T. Swift]

Predicted Failure

Skin / Frame at Limit Load % Improvement

2024 - T3 / 7075 - T651 18.2( ksi ) 125( Mpa )

2524 - T3 / 7150 - T7xx 21.2 ( ksi ) 146( Mpa ) 16.6%

2524 - T3 / 7055 - T7xx 21.2 ( ksi ) 146( Mpa ) 16.6%

Full 2 - Bay Longitudinal Crack with Central Broken Frame

Effects of bulging due to pressure & curvature

Localbending

Internalpressure

Crack length

[after T. Swift]

CrownAxial Stressat LimitLoad(ksi)

[after T. Swift]

2 - Bay Circumferential Crack with Central Broken Stringer

Failure Stress

Skin / Stringer @ Limit Load Failure % Improv

2x24 - T3 / 7075 - T6 30.5 ksi stringer

2x24 - T3 / 2024 - T3 18.3 ksi stringer ( - 40.0%)

2x24 - T3 / 7150 - T77511 34.4 ksi stringer 12.8%

2x24 - T3 / 7055 - T77511 42.5 ksi stringer 39.3%

Alcoa’s high strength 7xxx stringers significantly increase the 2-bay crack residual strength in the fuselage crown panel

Spar

CrownPanels

Side Panels

Upper Wing Cover

Lower Wing Cover

elasto - plastic

boundary

elasto - plasticboundary

C433 - T39 (panel 6) @ failure load

crack - tips

0.000

ASPAN-D Panel Design Software

16

Commercial Aerospace Design and Analysis Tools Example

2-Bay Circumferential Crack with Central Broken Stringer Failure Stress

Skin / Stringer @ Limit Load Failure % Improvement

2X24-T3 / 7075-T6511 30.5 ksi Stringer baseline2X24-T3 / 2024-T3511 18.3 ksi Stringer (-40%)2X24-T3 / 7150-T77511 34.4 ksi Stringer 12.8%2X24-T3 / 7055-T77511 42.5 ksi Stringer 39.3%

ASPAN -F Curved Panel Design Software

Output from Alcoa Stiffened Panel Analysis System (ASPAN), one of a suite of Alcoa-generated CAE tools, enables rapid design trade studies with new alloys,

materials & structural concepts

Alcoa’s 40 Year History with LNG Containers

Focus Areas:• 5000 Series Material Characterization

o Wrought and Welded Propertieso Static, Fatigue and Fracture o Room Temperature, -162C, -196C, 253C, and 269Co Corrosion and Sensitizationo Multiple Thickness’s ( 1” to 9”)o Crack Growth Rate Under Ship Spectrum Loadingo Leak Rates & Penetrated Crackso Residual Strength of Cracked Specimens

• Design and Manufacturing Studieso Welding, Forming, Handling, and Assembly Guidelineso Design Guidelines

Agenda

Meeting Challenges with Alcoa’s Collaborative Development Approach (ACDA)

Aluminum Design Innovation Leadership

Aluminum Design Development Approach

Design Challenges for the 21st Century Navy

18

Multiscale Design: Atoms to Ships

19

Requirements:• Mission• Cost• Operating environment• Rules

Production:• Capital • Sourcing• Efficiency• Cost

Grillage

Alloy composition and microstructure

Scantlings

Material:• Alloys/Tempers• Product form

Plate

Extrusions

PanelMechanical Behavior

20

Alcoa’s Integrated Approach to Design

Quality Process

Freq

uenc

y

Material Design

b b2R

InhomogeneityCrack

New Design

Manufacturing Process

PUMP

Functional Performance

Number of Cycles

Stre

ss L

evel

21

Quality-Performance Linkage

One important fundamental premise of this work is the existence of a quantifiable link(s) among material processing, microstructure and long-term structural

performance

Reduce initial flaw size population (initial quality)

Life

Economic Limit

Category I (black)

Category III (red)

Flaw

Siz

e

22

Use of Weld Specification Discontinuity Limits

Category I : Fatigue critical joints

Category II : Strength critical joints

Category III : Non Critical jointsFillet Weld Discontinuity Limits Determined by Metallographic Analysis

Item No.

Item DescriptionCategory I Category II Category III

1Weld Thickness (WT )

WT > 0.7t WT > 0.7t WT > 0.6t

2Fillet Leg Size (L)

L > 1.5 t L > 1.5 t L > t

3Weld Convexity (CV)

CV < 3 mm andα > 110 degrees

CV < 4 mm andα > 100 degrees

CV < 4 mm

23

Examples of ALCOA’s Fatigue Design Capability

Pressurized Truck Container

Problem Cracking in weld area Very expensive repair

SolutionHigh strains in area of crackingFatigue life similar to actual lifeMultiple solutions proposedLow cost solution implemented

24

Importance of Baseline Weld Specification

• Links All Product Development/Production Components (Design, Manufacturing, Quality)

• Design Process Improvements (More systematic/rule based; Links design/mfg to structural performance)

• Manufacturing Process Improvements (More traceability/monitoring world wide)

• Quality Assurance Improvement (Consistent/Relevant Measurement methods & traceability)

• Consistency/Reliability

• Enables Systematic Continuous Improvement

25

Importance of Coupon and Substructure Testing

• Simplified Tests Can Be Very Helpful and Timely (Instead of Waiting for the Finished Product. Always look to anchor analyses with reality as early as possible)

• Account for Tests in Original Development Plan

• Both Coupon Level Tests and Subscale Tests

• Be Very Careful How Tests Are Designed, Executed, Evaluated & Used for Correlation

Naval Structures Initiative (NSI)

26

First formal engagement and contract activity (in recent history) between Alcoa and the Navy.

Support research and development of improved lightweight aluminum structures for LCS and other HSVs. Applied research Develop conceptual and advanced concepts Develop engineering designs Fabricate prototype hardware Perform laboratory and field tests

Alcoa and the Navy created IPTs with members from PEO Ships, NAVSEA 05, NSWCCD, ABS, Primes, Shipyards, and Naval Architects: IPTs were setup in March 2008 sub-IPTs for each LCS

Collaboration: Who should be involved?

PrimeShipbuilder

Naval Architects

Program Office

Technical WarrantHolders

ABS NSWC

Ship Design

Managers

28

Meeting the Ship Construction Challenge with Alcoa Expertise

elasto - plastic

boundary

Alcoa can provide the innovations in ship design and construction required by the Navy and industry to create more affordable vessels that will meet mission requirements

Design Rules & Tools Manufacturing Knowledge

Structural DesignMaterial Knowledge

Alcoa is a leader in aluminum alloy research and development

Alcoa is a proven industry partner for aluminum design solutions and can deliver trade studies for alternative designs to the Navy addressing

With decades of design and production experience in aluminum, Alcoa has a breadth of knowledge that can be applied to the optimization of naval design rules and tools

Alcoa’s advances in next-generation manufacturing technology

Design for Cost

Once structures are identified as opportunities for cost savings, Alcoa can begin to develop concepts

Collaboration with the customer(s) identifies requirements and targets

The baseline structure or component must be defined and agreed upon

The baseline is then cost modeled

As concepts are developed they are cost modeled

The concepts are then evaluated for the above criteria

This process continues as concepts are downselected and refined

29

ACDA Results for Naval Platforms

30

Solutions to reduce the shipbuilding costs and reduce the weight of the ship Each opportunity identified that required a solution in cost has resulted

in 50-70% savings in recurring manufacturing cost

Each opportunity identified that required a solution in weight has received between 15-60% savings in weight

Immediate payoffs: solutions are being inserted into LCS and JHSV

Results:• 50% lighter than steel alternative• Nearly half the cost• Rapid development cycle and delivered on time

Phase I Opportunity identified (April 2009):• Need for lightweight cargo tie down• Must be ready for JHSV-1: Dec 2009

Phase V Production (December 2009 -Present):• Contract award• ABS approval for JHSV• ABS Type Approval

ACDA

Example: JHSV structural fitting

First prototype tested within 90 days

31

Aluminum Design Development Approach

Alcoa uses design in support of – Alcoa-OEM application engineering activities– Design and material trade studies– Joint concept development programs– Integrated product development teams– Alloy/product development activities– New Test Development for Coupons and Substructures

Designing from Publicly Available Handbooks and Design Tools is Not Enough– A much deeper view of the material properties and design options are

required to optimize structure– The tools and material data for aluminum that many OEMs are designing

with are not as sophisticated as those Alcoa can offer– What you know is not the limit to what is out there

Agenda

Meeting Challenges with Alcoa’s Collaborative Development Approach (ACDA)

Aluminum Design Innovation Leadership

Aluminum Design Development Approach

Design Challenges for the 21st Century Navy

32

Design Challenges for the 21st Century Navy

• Green Navy• Total Ownership Cost: Life Cycle vs Acquisition Costs• Power Demand• Unmanned systems

Green Navy

• The Great Green Fleet– Fuel efficiency– Alternative fuels– Reducing the fleet’s carbon footprint

• Finding solutions:– Lightweight structure:

• Keane, Scher, Piskorski (2006) show weight savings factor of 0.47 for aluminum decking over steel baseline for a High Speed Sealift vessel

• Aluminum sandwich panels are 20% lighter than conventional aluminum decking

– Power generation: gas turbines– New materials

“By 2016, we are going to deploy the Great Green Fleet which is going to be powered entirely by alternative fuels. And by 2020 the Navy and Marine Corps will produce half of all our energy from alternative sources.” Honorable Ray Mabus, Secretary of the Navy, January 21, 2010

$, $ everywhere and not a buck to spend

• “"Total Ownership Cost includes all costs associated with the research, development, procurement, operation, and disposal of an individual weapon system over its full life.“ –NAVAIR Total Ownership Cost website

• Finding solutions:– ACDA: 50-70% savings in recurring manufacturing

cost– Design for Producibility– Fatigue properties in spectrum loading (both

initiation and propagation)– Design and material selection for corrosion control– Effect of lean manning on ship reliability,

maintainability and availability

Power: The Joules to Victory

• Sensors to find and track the threat: cruise missiles, ballistic missiles

• Power to fight: lasers and rail guns• Keys:

– Stiff aluminum structures:• Sandwich panels• Multi-hollow extrusions• I-core type structures

– Use aluminum’s conductive properties for power generation, storage, transmission

– Thermal management– Lightweight aluminum mounts

Unmanned systems

• Advances in unmanned systems are leading to the point where a surface combatant can project for far- reaching sea control and power projection

• The key for design:– The need to maximize the

unmanned systems carried per volume and minimizing weight impact

– The ability to quickly deploy these systems

– This is beyond modularity• Key challenges:

– Collaborative design approaches for modular systems

– Alternative joining: fastening and adhesives

ACDA developed marine solutions providing 40% cost reduction

38

Alcoa’s Aluminum Structural Design Potential

Alcoa Can:

• Optimize the performance of cost effective lightweight aluminum structures through its deep expertise in aluminum structural design and internally developed design tools

Leverage its proven integrated design approach to optimize aluminum designs from the material microstructure through fabrication and assembly to lifecycle management

Address aluminum marine structure design challenges such as stiffness and buckling, fatigue crack initiation and propagation, structural health monitoring, fire protection, corrosion, and fabrication while maintaining performance benefits

Design optimized aluminum structures enabled by new technologies in the areas of GMAW, FSW, Coatings, and Alloys and Alloy Processing.

39

Collaboration Challenge for Alcoa’s Aluminum Structural Design

Aluminum structural design competencies and design tools are a significant enablers for cost effective weight reduction

Alcoa has significant resources and expertise for developing optimized aluminum structures

Achieving next-generation breakthroughs in aluminum vessel designs will require significant collaboration with the ship builders, researchers and certification agencies

Alcoa stands ready to be a full partner in bringing its cutting-edge research capabilities to bear on current and future structural design challenges