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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
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Product design specification (PDS)
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Added Value
Performance:
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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
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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
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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
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Function, object, constraint ...
FunctionTie
BeamShaft
Column
Objective• Minimum cost• Minimum weight• Maximum energy
storage• etc.
ConstraintStiffnessStrengthGeometryCorrosion
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Optimasi Material:
Performance = f [F,G,M]
P = f [(Functional requirements),
(Geometric constraints),
(Material properties)]
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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
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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
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Screening using attribute limits
Ceramics Metals Polymers Composites
Steel
Copper
Lead
Polyethylene
PP
PTFE
Diamond
Silica
Cement
CFRP
GFRP
Fibreboard
Search region
B
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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
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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
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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
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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.
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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
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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
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ISSUES TO ADDRESS...
• Price and availability of materials.
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• 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
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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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• 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
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• 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
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• 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
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• 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
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Adapted from Fig. 6.22,
Callister 6e. (Fig. 6.22
adapted from M.F. Ashby,
Materials Selection in Mechanical Design,
Butterworth-Heinemann Ltd.,
1992.)
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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
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• 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
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• 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
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• 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
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• 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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