Material Selection Optimization in Manufacturing Process

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FUNCTIONAL CYCLE CONCEPT

OPPORTUNITY/

MARKET/NEED/

CUSTOMER

PRODUCT

DEVELOPMENT

CUSTOMER

SERVICES

DELIVERY

PRODUCTION

CONTROL

PROCESSINGPROCESS R&D

PROCESS

PLANNING

PRODUCTION

PREPARATION

PRODUCT

DESIGN

CONCEPTUAL

DESIGNRECYCLING

DISPOSAL

INTEGRATED

DATABASEINTEGRATED

DATABASEINTEGRATED

DATABASEINTEGRATED

DATABASE

ADDED VALUEImprovementInventionInnovation BMW/CQT

LOGISTIC &

PROCRUMENT 2

4

Product design specification (PDS)

5

Added Value

Performance:

6

The world of materials, processes and shapes

MATERIALS

SHAPES

PROCESSES

• Ceramics

• Glasses

• Polymers

• Metals

• Elastomers

• Composites

• Natural materials

• Axisymmetric

• Prismatic

• Flat sheet

• Dished sheet

• 3-D solid

• 3-D hollow

• Deformation

• Moulding

• Powder methods

• Casting

• Machining

• Composite forming

• Molecular methods

A

4 7

Data organisation: materials

• “Handbook” data

• Hierarchical structure

• Idea of a “generic” and “specific” records

• Data-ranges stored at each level

Kingdom FamilyClass & member Attributes

Ceramics

Glasses

Polymers

Metals

Elastomers

Composites

Natural

Steels

Cu-alloys

Al-alloys

Ti-alloys

Ni-alloys

Zn-alloys

1000

2000

3000

4000

5000

6000

7000

8000

Density

Modulus

Strengths ...

Thermal props.

Electrical props.

Corrosion props.

Processes

Shapes

Pointers to unstructured information

MATERIAL A material

record

A

5 8

Case: Structured data for ABS

•General Properties•

•Density 1.05 - 1.07 Mg/m^3•Price 2.1 - 2.3 USD/kg

•

•Mechanical Properties

•Bulk Modulus 4.1 - 4.6 GPa•Compressive Strength 55 - 60 MPa•Ductility 0.06 - 0.07•Elastic Limit 40 - 45 MPa•Endurance Limit 24 - 27 MPa•Fracture Toughness 2.3 - 2.6 MPa.m1/2

•Hardness 100 - 140 MPa•Loss Coefficient 0.009 - 0.026•Modulus of Rupture 50 - 55 MPa•Poisson's Ratio 0.38 - 0.42•Shear Modulus 0.85 - 0.95 GPa•Tensile Strength 45 - 48 MPa•Young's Modulus 2.5 - 2.8 GPa

Acrylonitrile-butadiene-styrene (ABS) - (CH2-CH-C6H4)n

Thermal PropertiesGlass Temperature 350 - 360 K

Max Service Temp 350 - 370 K

Min Service Temp 150 - 200 K

Specific Heat 1500 - 1510 J/kg.K

Thermal Conductivity 0.17 - 0.24 W/m.K

Thermal Expansion 70 - 75 10-6/K

Electrical PropertiesBreakdown Potential 14 - 15 MV/m

Dielectric Constant 2.8 - 3.3

Resistivity 6.3x1021 - 1.6x1022 ohm.cm

Power Factor 0.008 - 0.009

Corrosion and Wear ResistanceFlammability Average

Fresh Water Good

Organic Solvents Average

Oxidation at 500C Very Poor

Sea Water Good

Strong Acid Good

Strong Alkalis Good

UV Good

Wear Poor

Weak Acid Good

Weak Alkalis GoodA

6 9

Function, object, constraint ...

FunctionTie

BeamShaft

Column

Objective• Minimum cost• Minimum weight• Maximum energy

storage• etc.

ConstraintStiffnessStrengthGeometryCorrosion

10

Optimasi Material:

Performance = f [F,G,M]

P = f [(Functional requirements),

(Geometric constraints),

(Material properties)]

11

Design requirements Material specification

From which we obtain …

• Screening criteria expressed as numerical limits on

material property-values

Or expressed as requirements for processing,

corrosion, ….

• Ranking criteria based on material indices that

characterise performance.

Design concept

Analyse: Function What does the component do ?

Objective(s) What is to be maximised or minimised ?

Constraints What essential conditions must be met ?

Free variables Which design variables are free ?

“Translation”

B

212

Screening using constraints“Eliminate materials that can’t do the job”

Screen on attributes

Requirements: must

• operate at 100oC

• be electrical insulator

• conduct heat well

Retain materials with:

• max operating temp > 100C

• resistivity R > 1020 .cm

• T-conduct. > 100 W/m.K

Example: heat exchanger tubes

Screen on links Example: cheap metal window frame

Requirements: must

• be extrudable

Retain materials with:

• links to “extrusion”

Screen on both attributes and links

B

313

Screening using attribute limits

Ceramics Metals Polymers Composites

Steel

Copper

Lead

Polyethylene

PP

PTFE

Diamond

Silica

Cement

CFRP

GFRP

Fibreboard

Search region

B

414

Screening using attribute limits

Material ClassMaterials:\Ceramic Materials:\Metal Materials:\Polymer Materials:\Composite

Ela

stic L

imit (

MP

a)

1.

10.

100.

1000.

Ceramics Metals Polymers Composites

Diamond

Aerated Concrete

Silica

Silicon Nitride

Tungsten, Commercial Purity

Lead

Copper

Acetal

Butadiene

PolyUrethane

CFRPee

MDF

Fibreboard

Search region

B

515

Material indices: the light, strong tie-rodStrong tie of length L and minimum mass

L

FF

Area A

Function

Objective

Tie-rod

Free variable

Contraints

Minimise mass m

Length L is specified

Must not fail under load F

Cross-section area A is free

Equation for objective: m = A L (1)

Equation for constraint: F/A < y (2)

Eliminate A in (1) using (2):

Minimise the material index

y

FLm

y

B

616

Materials indices

Minimum cost

Minimum

weight

Maximum energy

storage

Minimum

environ. impact

FUNCTION

OBJECTIVE

CONSTRAINTS

INDEX

Tie

Beam

Shaft

Column

Mechanical,

Thermal,

Electrical...

Stiffness

specified

Strength

specified

Fatigue limit

Geometry

specified

2/1EM

Minimise this!

Each combination of

Function

ObjectiveConstraintFree variable

Has a

characterising

material index

B

717

Case Study

• Choose one product

• Find the mechanical properties, thermal properties, electrical properties and corrosion and wear resistance properties

• Analyze the functions, objectives, constraints, and free variables of your product.

18

Material indices: the key to optimised choice

Cost, Cm

Density,

Modulus, E

Strength, y

Endurance limit, e

Thermal conductivity,

T- expansion coefficient,

the “Physicists” view of materials, e.g.

Material properties --

the “Engineers” view of materials

Material indices --

Function Stiffness Strength

Tension (tie)

Bending (beam)

Bending (panel)

ρ/E yρ/σ

1/2ρ/E2/3

yρ/σ

Objective: minimise mass

Many more: see Appendix B of the Text

Minimise these!

1/3ρ/E 1/2y

ρ/σ

B

819

Optimised selection using charts

Index 1/2E

ρM

22 M/ρE

MLog2Log2ELog

Contours of constant

M are lines of slope 2

on an E- chart

CE

CE 2/1

CE 3/1

0.1

10

1

100

Metals

Polymers

Elastomers

Woods

Composites

Foams0.01

1000

1000.1 1 10Density (Mg/m3)

Young’s

modulu

s E

, (G

Pa)

Ceramics

1

2 3

B

920

Selection using hard-copy charts

CE 2/1

Search

region

B1

021

Selection using the CES software

Density (Mg/m^3)1. 10. 100.

Yo

ung

's M

od

ulu

s (

GP

a)

0.1

1.

10.

100.

1000.

PolyUrethane

PTFE

PVC foam

Sandstone

Polyethylene

Carbon Steel

Tungsten

Aluminium alloys)

Diamond

CFRP

Density (Mg/m3)

Ceramics

Metals

Elastomers

Composites

Polymers

Woods

Foams

Search

region

CE 2/1

B1

122

ISSUES TO ADDRESS...

• Price and availability of materials.

1

• How do we select materials based on optimal

performance?

• Applications:--shafts under torsion

--bars under tension

--plates under bending

--materials for a magnetic coil.

MATERIALS SELECTIONECONOMIC, ENVIRONMENTAL, & DESIGN ISSUES

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2

• Current Prices on the web(a):--Short term trends: fluctuations due to supply/demand.

--Long term trend: prices will increase as rich deposits

are depleted.

• Materials require energy to process them:

--Energy to produce

materials (GJ/ton)

Al

PET

Cu

steel

glass

paper

237 (17)(b)

103 (13)(c)

97 (20)(b)

20(d)

13(e)

9(f)

--Cost of energy used in

processing materials ($/GJ)(g)

elect resistance

propane

natural gas

oil

25

11

9

8a http://www.statcan.ca/english/pgdb/economy/primary/prim44.htm

a http://www.metalprices.com

b http://www.automotive.copper.org/recyclability.htm

c http://members.aol.com/profchm/escalant.html

d http://www.steel.org.facts/power/energy.htm

e http://eren.doe.gov/EE/industry_glass.html

f http://www.aifq.qc.ca/english/industry/energy.html#1

g http://www.wren.doe.gov/consumerinfo/rebriefs/cb5.html

Energy using recycled

material indicated in green.

PRICE AND AVAILABILITY

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3

• Reference material:

--Rolled A36 plain

carbon steel.

• Relative cost, $,

fluctuates less

over time than

actual cost.

Based on data in Appendix

C, Callister, 6e.AFRE, GFRE, & CFRE = Aramid,

Glass, & Carbon fiber reinforced

epoxy composites.

$ $ /kg

($ /kg)ref material

RELATIVE COST, $, OF MATERIALS

25

4

• Bar must not lengthen by more than d

under force F; must have initial length L.

• Maximize the Performance Index:

-- Stiffness relation: -- Mass of bar:

F

c2 E

d

L( = Ee) M Lc2

• Eliminate the "free" design parameter, c:

M

FL2

d

E

P

E

specified by applicationminimize for small M

(stiff, light tension members)

STIFF & LIGHT TENSION MEMBERS

26

5

• Bar must carry a force F without failing;

must have initial length L.

• Maximize the Performance Index:

-- Strength relation: -- Mass of bar:

M Lc2

• Eliminate the "free" design parameter, c:

specified by applicationminimize for small M

P

f

(strong, light tension members)

M FLN

f

f

N

F

c2

STRONG & LIGHT TENSION MEMBERS

27

6

• Bar must carry a moment, Mt ;

must have a length L.

• Maximize the Performance Index:

-- Strength relation: -- Mass of bar:

• Eliminate the "free" design parameter, R:

specified by application minimize for small M

(strong, light torsion members)

f

N

2Mt

R3 M R2L

M 2 NMt 2 /3

L

f2 /3

P

f2 /3

STRONG & LIGHT TORSION MEMBERS

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DATA: STRONG & LIGHT TENSION/TORSION MEMBERS

Increasing P

for strong

tension

members

Increasing P

for strong

torsion members

0.1 1 10 30

1

10

102

103

104

Density, (Mg/m3)

Strength, f(MPa)

0.1

Metalalloys

Steels

Ceramics

PMCs

Polymers

|| grain

grain

Cermets

7

Adapted from Fig. 6.22,

Callister 6e. (Fig. 6.22

adapted from M.F. Ashby,

Materials Selection in Mechanical Design,

Butterworth-Heinemann Ltd.,

1992.)

29

0.1 1 10 300.1

1

10

102

103

104

Cermets

Steels

Density, (Mg/m3)

Str

en

gth

,

f(M

Pa

)

Increasing P

for strong

bending members

Metalalloys

Ceramics

PMCs

Polymers

|| grain

grain

8

• Maximize the Performance Index:

P

1/2

Adapted from Fig. 6.22,

Callister 6e. (Fig. 6.22

adapted from M.F. Ashby,

Materials Selection in Mechanical Design,

Butterworth-Heinemann Ltd.,

1992.)

DATA: STRONG & LIGHTBENDING MEMBERS

30

9

• Other factors:--require f > 300MPa.

--Rule out ceramics and glasses: KIc too small.

• Maximize the Performance Index:

P

f2 /3

• Numerical Data:

• Lightest: Carbon fiber reinf. epoxy

(CFRE) member.

material

CFRE (vf=0.65)

GFRE (vf=0.65)

Al alloy (2024-T6)

Ti alloy (Ti-6Al-4V)

4340 steel (oil

quench & temper)

(Mg/m3)

1.5

2.0

2.8

4.4

7.8

P (MPa)2/3m3/Mg)

73

52

16

15

11

Data from Table 6.6, Callister 6e.

f (MPa)

1140

1060

300

525

780

DETAILED STUDY I: STRONG, LIGHT TORSION MEMBERS

31

10

• Minimize Cost: Cost Index ~ M$ ~ $/P (since M ~ 1/P)

• Numerical Data:

• Lowest cost: 4340 steel (oil quench & temper)

material

CFRE (vf=0.65)

GFRE (vf=0.65)

Al alloy (2024-T6)

Ti alloy (Ti-6Al-4V)

4340 steel (oil

quench & temper)

$80

40

15

110

5

P (MPa)2/3m3/Mg)

73

52

16

15

11

($/P)x100

112

76

93

748

46

• Need to consider machining, joining costs also.

Data from Table 6.7, Callister 6e.

DETAILED STUDY I: STRONG, LOW COST TORSION MEMBERS

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