Incorporating Green Engineering in Material Selection and Design
S.L. Kampe
Associate ProfessorMaterials Science and Engineering Department
Virginia Tech
18th Annual National Educators’ Workshop19-22 October 2003Newport News and Hampton, Virginia
Materials Science and Engineering2003 National Educators’ Workshop
Material Selection and Design - Background
∆ MSE 4055 - Material Selection and Design• MSE required, senior level• Technical elective for ISE, ESM, ME, AOE, Arch, + others.• Material Selection as it influences the outcomes of engineering design
– in a general sense– green issues
∆ Methodology- Identification of appropriate material selection indices
i. Define design objectiveii. Determine constitutive relationshipiii. Separate design needs (extensive) from material response groups (intensive)
- 2-D material selection charts in the manner of AshbyM.F. Ashby, Materials Selection in Mechanical Design, 2nd Ed., B-H, Oxford, 1999.
- Cambridge Engineering Selector application softwareCES4.1, Granta Design, Ltd., 2003
∆ Disclaimers- Illustrative of an approach- Several layers of analysis required- Not a final solution to the complex problem
Materials Science and Engineering2003 National Educators’ Workshop
Examples
• Selecting a material to solve a specific environmental problem
» Identify a suitable alternative to asbestos as an insulating material
• Enabling the routine assessment of green issues in generic engineering design » Lifetime Energy Consumption attributable to a component placed in
a transportation system
Materials Science and Engineering2003 National Educators’ Workshop
TLC = Initial Cost + Lifetime Operational Costs
An alternative to asbestos insulation
Objective: Identify an insulating material to replace asbestos to reduce total lifetime cost (TLC).
r
CE = Exchange Constant = $-value of Energy ( $ / J)
TLC ( $ / m2 ) ≈ · CM· r + k
Tr
tCE123
123
Material Contribution
123
design requirements
123123 123
(e.g., due to heat losses)(purchase price of the material) Design Needs
r = thickness (m)
T = temperature difference (K)
Material Response Constants
= material density (kg/m3)
CM = per-mass cost ($/kg)
k = thermal conductivity (J/kg·K·s)
CE = exchange constant ($ / J)
Materials Science and Engineering2003 National Educators’ Workshop
Exchange Constant: the $-value of energy
Energy Source
CoalOil
Natural GasGasoline (US)
Gasoline (Europe)Electricity (resistance)
Cost ( US$ / MJ )
0.003 - 0 0040.007 - 0.0120.005 - 0.0080.012-0.0150.03-0.040.02 - 0.06
from M.F. Ashby, Materials Selection: Multiple Constraints and Compound Objectives, CUED/C-EDC/TR38, Cambridge Engineering Design Center, Cambridge University Engineering, April 1996, p.1.13
Exchange Constant
An alternative to asbestos insulation
Materials Science and Engineering2003 National Educators’ Workshop
Cambridge Engineering Selector (CES) Ver. 4.1
An alternative to asbestos insulation
Materials Science and Engineering2003 National Educators’ Workshop
Increasing Initial Cost
Incr
easi
ng C
ost
of
Opera
tion
Cambridge Engineering Selector (CES 3.1)
An alternative to asbestos insulation
Materials Science and Engineering2003 National Educators’ Workshop
Increasing Initial Cost
Incr
easi
ng C
ost
of
Opera
tion
Cambridge Engineering Selector (CES 3.1)
An alternative to asbestos insulation
Materials Science and Engineering2003 National Educators’ Workshop
Increasing Initial Cost
Incr
easi
ng S
erv
ice C
ost
Selected Candidate Materials
Property-range midpoint valuesFrom CES3.1, 2000
0.01
0.1
1
101 102 103
Th
erm
al C
on
du
ctiv
ity,
W/m
·K
( R
ela
tes
to C
ost
of
En
erg
y L
ost
Du
rin
g S
erv
ice
)
Density · Price, US$/m3
( Relates to Initial Cost )
Hokie Stone (Limestone)
Cement
Cork
Cordierite Foam
Cellulose Insulation
Mullite Foam
PE FoamGlass Wool
Melamine Foam
PU Elastomeric Foam
Vermiculite
LD Flexible Polymer
PU Foam
Plaster of Paris
Glass Foam
Asbestos
An alternative to asbestos insulation
Materials Science and Engineering2003 National Educators’ Workshop
Coal as an Energy Source
An alternative to Asbestos Insulation
Assumed Design Needs
T ≈ 40 K
r ≈ 7 cm
t = 0.5 (blue) or 5 year (red)
Assumed Material Response
kasbestos ≈ 0.4 W/m·K
( * CM)asbestos ≈ 494 $/m3
Increasing Initial Cost
Incr
easi
ng S
erv
ice C
ost
0.01
0.1
1
101 102 103
Th
erm
al C
on
du
ctiv
ity,
W/m
·K
( R
ela
tes
to C
ost
of
En
erg
y L
ost
Du
rin
g S
erv
ice
)
Density · Price, US$/m3
( Relates to Initial Cost )
Hokie Stone (Limestone)
Cement
Cork
Cordierite Foam
Cellulose Insulation
Mullite Foam
PE FoamGlass Wool
Melamine Foam
PU Elastomeric Foam
Vermiculite
LD Flexible Polymer
PU Foam
Plaster of Paris
Glass Foam
0.5-year Lifetime
5-year Lifetime
Asbestos
Lines of Comparable Lifetime Cost (relative to Asbestos)
Contours of Decreasing Lifetime Cost
Materials Science and Engineering2003 National Educators’ Workshop
Lifetime Energy Consumption - Transportation Systems
Ex. A component on a transportation system loaded in bending- L fixed by design- P predicted by design
Constitutive Equations:
McI
3PL2
4bh2 mAL
m 3
4 2P L7 / 2
2 / 3
f
2/ 3
Minimum mass (e.g., kg) required to
fulfill requirements of strength-limited design (fixed beam aspect ratio)
Q 3
4 2P L7 / 2
2 / 3
q
f2 / 3
Energy (e.g., MJ) required to fulfill requirements of strength-limited design, for q in MJ/kg
P = distributed load (e.g., N/m)L = length (e.g., m)b,h = cross sectional dimensions (e.g., m)
= failure stress (e.g., MPa)
= density (e.g., kg/m3)
q = Energy content (e.g., MJ/kg)
Materials Science and Engineering2003 National Educators’ Workshop
LEC 3
4 2P L7 / 2
2 / 3
q
f2 / 3
3
4 2P L7 / 2
2 / 3
f2 / 3
CE
Lifetime Energy Consumption (LEC) = Initial Energy Expenditure+ Energy Expended during Service
Exchange constant relating mass to energy expenditure
LEC/
q
f2 / 3
f2 / 3
CE P = distributed load (e.g., N/m)
L = length (e.g., m)b,h = cross sectional dimensions (e.g., m)
f = failure stress (e.g., MPa)
= density (e.g., kg/m3)
q = Energy content (e.g., MJ/kg)
Lifetime Energy Consumption - Transportation Systems
Objective: Minimize Lifetime Energy Consumption
Materials Science and Engineering2003 National Educators’ Workshop
Estimating an Exchange Constant
Hypothetical Example:
• 3,000 kg vehicle: 14 mpg • Energy value of Gasoline ≈ 126 MJ/gal1,800 kg vehicle: 19 mpg • 50,000 mile lifetime
50,000mileslifetime
xgal. fuel14miles
x126MJ
gal. 450,000
MJ consumedlifetime
50,000mileslifetime
xgal. fuel19miles
x126MJ
gal. 331,580
MJ consumedlifetime
CE
MJm
(450,000 331,580) MJ
(3,000 1,800) kg99
MJkg
For the 3,000 kg vehicle and a 50,000 mile lifetime:
For the 1,800 kg vehicle and a 50,000 mile lifetime:
Lifetime Energy Consumption - Transportation Systems
Materials Science and Engineering2003 National Educators’ Workshop
10
100
104 105
Ma
ss In
de
x
/
2/3
( kg
/ m
5/3
·MN
2/3 )
Strength-limited Energy Index
·q / 2/3 ( MJ / m
5/3·MN
2/3 )
Epoxy-Kevlar Composite
1015 Steel403 SS
6061-T6
Mg AZ61 Alpha Ti Gr 6
Ti MMCCFRP
GFRP
Be S-200
Al Foam
Alumina CMC
Increasing Initial Energy Expenditure
Incr
easi
ng L
ifeti
me E
xpendit
ure Selected Candidate Materials
Property-range midpoint valuesFrom CES3.1, 2000
Lifetime Energy Consumption - Transportation Systems
Materials Science and Engineering2003 National Educators’ Workshop
10
100
104 105
Ma
ss In
de
x
/
2/3
( kg
/ m
5/3
·MN
2/3 )
Strength-limited Energy Index
·q / 2/3 ( MJ / m
5/3·MN
2/3 )
Epoxy-Kevlar Composite
1015 Steel403 SS
6061-T6
Mg AZ61 Alpha Ti Gr 6
Ti MMCCFRP
GFRP
Be S-200
Al Foam
Alumina CMC
CE = 99 MJ/kg
( 50,000 mi. lifetime )
CE = 395 MJ/kg
( 200,000 mi. lifetime )
Increasing Initial Energy Expenditure
Incr
easi
ng L
ifeti
me E
xpendit
ure
Lifetime Energy Consumption - Transportation Systems
Materials Science and Engineering2003 National Educators’ Workshop
Increasing Initial Energy Expenditure
Incr
easi
ng L
ifeti
me E
xpendit
ure
10
100
104 105
Ma
ss In
de
x
/
2/3
( kg
/ m
5/3
·MN
2/3 )
Strength-limited Energy Index
·q / 2/3 ( MJ / m
5/3·MN
2/3 )
Epoxy-Kevlar Composite
1015 Steel403 SS
6061-T6
Mg AZ61 Alpha Ti Gr 6
Ti MMCCFRP
GFRP
Be S-200
Al Foam
Alumina CMC
CE = 395 MJ/kg
( LEC' = 0.5·LEC'o )
CE = 395 MJ/kg
( 200,000 mi. lifetime )
Lifetime Energy Consumption - Transportation Systems
Materials Science and Engineering2003 National Educators’ Workshop
Summary
• Material selection is a decision-requiring event in design
• Green-based material selection indices and charts provide a means to routinely assess environmental issues relevant to the decision-making process
• One of several criteria necessary to consider in design
Note: Contents of this talk can be found in the following published manuscripts:
• S.L. Kampe, “Method to Incorporate Green Engineering in Material Selection and Design,” Proceedings of the American Society for Engineering Education Annual Conference and Exposition, (Proc. Int. Conf., Montreal, 17-19 June 2002), ASEE, Washington, D.C., 2002, pp. 1625.1-1625.7. http://www.asee.org/conferences/proceedings/search.cfm
• S.L. Kampe, “Incorporating Green Engineering in Materials Selection and Design,” 2001 Green Engineering Symposium Proceedings (Proc. Conf., Roanoke, Virginia, August 2001), Blacksburg, 2001, pp. 7-1 – 7-6. Also featured at http://www. grantadesign.com/userarea/papers/cust1.htm.
Incorporating Green Engineering in Material Selection and Design
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