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8/13/2019 Material Design Report
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Abstract
The objective report is to design a suitable material and geometry for wind turbine tower and blades. A
limits of constraints are set for the design of material. The tower and blades must be resistant to UV,
function temperature must be between -40oC to 40oC in a marine environment. In order to find the
optimum shape and dimensions, an excel spreadsheet is established to aid in this process. A few possible
dimensions is inputted to compare the effects on design stress, elastic modulus and cross-section area. The
material index based on stiffness-limited applications and strength-limited applications are worked out by
deriving equation 1, equation 2 and equation 3 stated under Task 1. Top 3 materials are chosen
respectively for tower and blades using CES EduPack. Eco-Audit process is carry out to determine the
energy use for each material from manufacture to end of life. The optimum shape and dimensions
obtained is hollow circle section with outer diameter 4.5m and inner diameter 3.5m. The top 3 materials
for tower are silicon carbide, alumina and silicon nitride. While the top 3 materials for blades are cast Al-
alloys, age-hardening wrought Al-alloys and non-age-hardening wrought Al-alloys. After analyzing the
suitability of top 3 materials for both tower and blades, silicon carbide and cast Al-alloys are chosen as thebest materials for both tower and blades respectively. The minimum weight of the tower calculated by
multiplying the density of material, cross section area selected for best geometry and height of tower is 1,
558, 184kg and the construction cost calculated by multiplying the weight and price is RM71, 209, 008.80.
Introduction
In the past few years, people are becoming more concern about environmental issues such as
increase in greenhouse gases, air pollution and global warming. The major contributor to these issues is
the usage of fossil fuels. To solve this problem, renewable energy resources such as wind energy are being
explored to replace fossil fuels. Therefore, the importance of offshore wind farms as a source of renewable
energy has drastically increased.
The growing importance of wind energy drives the wind industry to develop larger, lighter, and
cheaper wind turbine towers and blades. The design is always a matter of constant tradeoff between
demands of lower cost, better energy productivity, increased lifetime, reliability and durability. In order to
acquire an optimum design of wind turbine, we have to take into considerations of the shape and
parameters of turbine tower, the durability of material and also the cost of material. The process of
manufacturing and building the wind turbine and its effect to environment is also taken into consideration.
CES EduPack is used to choose the best material for tower and blades according to certain
requirement and constraints. The function, constraints, objectives and free variables are determined beforechoosing the optimum material and shape.
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
DESIGN FACTORS OFFSHORE WIND TURBINE TOWER
FUNCTION To support the turbine generatorCONSTRAINTS Function temperature :-40oC to 40oC in a marine environment
Resistant to UV Resistant to corrosion Must not fracture in brittle manner Must not buckle Deflection at top < 5cm Fixed tower height : 80m Longest Edge of Cross Section Area < 5m
FREE VARIABLES The material used Diameter of turbine tower (within 5m) Geometry of tower Cross-section area of tower
OBJECTIVE To design a low density, cost and strong turbine towerTable 1: Design factors of offshore wind turbine tower
DESIGN FACTORS OFFSHORE WIND TURBINE BLADE
FUNCTION To carry their own weight To take loads exerted on them by the wind
CONSTRAINTS Function temperature :-40oC to 40oC in a marine environment Must be stiff, strong and light Resistant to UV Resistant to corrosion Minimum fracture toughness : 15MPa1/2 Fatigue strength criterion of 100MPa at 107cycles Fixed width and length of blades
FREE VARIABLES The material usedOBJECTIVE To design a low density, cost and stiff turbine blade
Table 2: Design factors of offshore wind turbine blade
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Task 1
The wind turbine tower has the function of supporting the turbine generator. It will also be
exposed to UV and corrosive nature of marine environment. Therefore it is important to choose a suitable
geometry and material that can overcome these problems.
4 types of uniform cross section of pillars (Figure 1) are taken into consideration in choosing the
most efficient geometry. The most efficient geometry should have the minimum E, y and cross sectional
area A to reduce cost and weight. The 4 types of uniform cross section are solid circle section, hollow
circle section, solid square section and hollow square section. Different possible dimensions are used to
compare the effect on cross sectional area A, minimum required modulus E and minimum design stress .
The optimized shape and dimensions with the highest geometry performance index is chosen.
The minimum required modulus E and minimum design stress are obtained by rearranging
equation 1 and 2. The failure load F which is the wind load and height of tower L is fixed. The equation
for I and ymis as stated in Figure 1 and the max deflection is fixed at 0.05m.
y =
E =
Geometry performance index=
Failure load F 1x106N
Height of tower L 80m
Figure 1: Four different cross-section shapes for Tower design selection
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
An Excel spreadsheet is established to aid in choosing the most efficient geometry. The change in
cross sectional area A, minimum required modulus E and minimum design stress is observed by
inputting different possible dimensions (T, D, d, t). Safety factor of 2 is used to find design stress.
Types of
GeometryIndex
Failure
Load
Tower
heightDeflection
D/T
(m)
d/t
(m)
Ym
(m)
Cross-sectional
Area (m^2)
Solid
Circle
Section
1 1.00E+06 80 0.05 5 0 2.5 19.63495408
2 1.00E+06 80 0.05 4.5 0 2.25 15.90431281
3 1.00E+06 80 0.05 4 0 2 12.56637061
Hollow
Circle
Section
4 1.00E+06 80 0.05 5 4 2.5 7.068583471
5 1.00E+06 80 0.05 4.5 3.5 2.25 6.283185307
6 1.00E+06 80 0.05 4 3 2 5.497787144
Solid
Square
Section
7 1.00E+06 80 0.05 5 0 2.5 19.63495408
8 1.00E+06 80 0.05 4.5 0 2.25 15.90431281
9 1.00E+06 80 0.05 4 0 2 12.56637061
Hollow 10 1.00E+06 80 0.05 5 4 2.5 7.068583471
Square
Section
11 1.00E+06 80 0.05 4.5 3.5 2.25 6.283185307
12 1.00E+06 80 0.05 4 3 2 5.497787144
Types of
GeometryIndex
Second
Moment
of Area, I
Design stress,
(MPa)
Elastic
modulus,
E(GPa)
Geometry
Performance
Index
Solid
Circle
Section
1 30.67961576 1.30E+01 111.2573691 7.39E+01
2 20.1288959 1.79E+01 169.5737983 1.91E+02
3 12.56637061 2.55E+01 271.6244362 5.50E+02
Hollow
Circle
Section
4 18.11324514 2.21E+01 188.4440533 5.89E+02
5 12.76272016 2.82E+01 267.4455987 1.20E+03
6 8.590292412 3.73E+01 397.3477467 2.69E+03
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Solid
Square
Section
7 52.08333333 7.68E+00 65.536 2.56E+01
8 34.171875 1.05E+01 99.88721232 6.62E+01
9 21.33333333 1.50E+01 160 1.91E+02
Hollow
Square
Section
10 30.75 1.30E+01 111.00271 2.04E+02
11 21.66666667 1.66E+01 157.5384615 4.17E+02
12 14.58333333 2.19E+01 234.0571429 9.34E+02
Maximum= 2.69E+03
Table 3: Possible geometry and dimension and effect on area, elastic modulus and design stress
From the excel sheet above, the 6th
geometry has the highest geometry performance index whichis 2.24E+04. However, it has a relatively highly high Youngs modulus which is 397GPa which only a
few materials can achieve that value. Thus the 5thgeometry with the second highest geometry
performance index is chosen. Therefore the optimized shape and dimensions obtained is hollow circle
section with outer diameter 4.5m and inner diameter 3.5m.
In strength-limited applications, deflection is allowable as long as the component does not fail and
strength is the active design constraint. While in stiffness-limited applications, elastic deflection is the
active design constraint. To work out the material performance index (MI), the equation below is
necessary.
F = ----- (Equation 1)
= ----- (Equation 2)
m = *A*L----- (Equation 3)
Where F = Failure Load,
I = Second Moment of Area, y = yield strength,
ym= Distance between neutral axis of the beam and its outer most surface
L = Height of tower, m = Mass of Material
= Density of Material, A = Cross-section Area
= Deflection, E = Elastic Modulus
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
In order to work out the material performance index (MI) based on strength-limited application,
Equation 1 and Equation 3 is needed. The uniform cross-section area is assumed to be a solid square.
Safety factor S is applied. = S*y where is the design stress.
Workings to find material index:
Sub I =and ym =
into the equation (1)
F =
F = ----- (1)
Sub A = T2 into the equation (3)
M = * T2*L
T = ----- (2)
Sub (2) into (1)
F =
6FL
=
MI =
Design guidelines:
Log (MI) = Log
Log (MI) = LogLog
Log= Log+ Log (MI)Compared to y = mx + c
Slope, m =
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8/13/2019 Material Design Report
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
By using CES EduPack, the top 5 materials with the highest performance index is chosen with
certain constraints. The constraints considered include functional temperature of -40oC to 40
oC, high
durability towards salt water and excellent durability towards marine environment and UV radiation.
Minimum elastic modulus and design stress obtained in task 1 from the best geometry is also set as limits.
Yield strength is plotted against density*price as cost and weight of material is considered. The material
with highest performance index is silicon carbide, followed by alumina, silicon nitride, boron carbide and
tungsten carbides.
Figure 2: CES EduPack material selection results
Among the 5 selected materials, silicon carbide is the best option. This is because silicon carbide
has lower density*price value and yet has a similar yield strength to the other four materials.
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Task 2
The most important material criteria of turbine blades is to be stiff, strong and light. This is
because turbine blades have to carry their own weight on the same time take loads exerted on them by the
wind. It is also better if the material requires less maintenance as maintenance process of turbines is hard.
Thus, a more expensive material with longer lifespan can be chosen if it cuts down on maintenance.
In order to work out the material performance index (MI) based on stiffness-limited application,
Equation 2 and Equation 3 is needed.
Workings to find material index:
Sub I =into the equation (2)
=
= ----- (1)
Sub A = T2 into the equation (3)
M = * T2*L
T2=----- (2)
Sub (2) into (1)
=
( )
=
=
MI =
Design guidelines:
Log (MI) = Log
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Log (MI) = Log2LogLog= Log+ Log (MI)
Compared to y = mx + c
Slope, m = 2
By using CES EduPack, the top 5 materials with the highest performance index is chosen with
certain constraints. The constraints considered include functional temperature of -40oC to 40
oC and
excellent durability towards marine environment and UV radiation. Elastic modulus is plotted against
density times price as cost and weight of material is considered. The material with highest performance
index is cast Al-alloys, followed by age-hardening wrought Al-alloys, non-age-hardening wrought Al-
alloys, aluminum/silicon carbide composite and brass.
Figure 3: CES EduPack material selection results
After the top 5 materials is chosen, the next design consideration is against fatigue. The blades
should be able to go throught an estimated 1 billion loading cycles through their lifetime. A minimum
fracture toughness of 15MPam1/2and a fatigue strength criterion of 100MPa at 107 is applied. The top 3
materials chosen with fracture toughness and fatigue strength limits are cast Al-alloys, age-hardening
wrought Al-alloys and non-age-hardening wrought Al-alloys.
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Figure 4: CES EduPack material selection results
Among the three materials, the best option is cast Al-alloys. This is because the top threematerials have almost the same density*price but yet cast Al-alloys have the highest Youngs modulus.
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Corrosion Protection for both Tower and Blade
The offshore wind turbine is exposed to marine and corrosive environment. It is possible that the
wind turbine will corrode and affect its performance. Thus the type of corrosion, the cause of the corrosion
and its protection measurement must be identified to protect the wind turbine.
Design
Object
Possible Corrosion
Type
Responsible Environmental
Condition
Corrosion Protection
Measurement
Tower
Uniform corrosion
Presence of sea water uniformly
distributed around the lower
part of tower
Apply coating on material
surface
Crevice corrosionPresence of crevice in tower
that stores stagnant water
Use cathodic protection Use higher resistant
material
Microbiologically
Influenced Corrosion
(MIC)
Interaction between
construction materials and
microbial activity
Regular mechanicalcleaning
Chemical treatmentwith biocides to control
population of bacteria
Erosion corrosion High flow rate of wave Use cathodic protection
Blade
Fretting corrosion
Constant rubbing contact
between two moving metal
surfaces
Apply lubricationbetween contact
surfaces
Erosion corrosion High wind speedUse cathodic protection to
minimize erosion corrosion
Galvanic corrosion Presence of moisture in air Apply coating on materialsurfaces
Corrosion fatigue
Development of crack under
simultaneous action of
corrosion and cyclic stress due
to wind load
Use coating or inhibitors to
delay the initiation of corrosion
cracks
Table 3: Possible type corrosion and protection measurement
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Task 3 Eco-Audits of Tower and Blade
Table 4: Energy use and CO2 footprint for silicon carbide tower
Phase Energy (J) Energy (%) CO2 (kg) CO2 (%)
Material 5.9e+12 99.7 5.25e+05 99.8
Manufacture 0 0.0 0 0.0
Transport 4.05e+07 0.0 2.87 0.0
Use 0 0.0 0 0.0
Disposal 1.6e+10 0.3 1.12e+03 0.2
Total (for first life) 5.92e+12 100 5.26e+05 100
End of life potential -5.66e+12 -5.08e+05
Table 5: Energy use and CO2 footprint for alumina tower
Phase Energy (J) Energy (%) CO2 (kg) CO2 (%)
Material 4.16e+12 99.6 2.25e+05 99.5
Manufacture 0 0.0 0 0.0
Transport 4.05e+07 0.0 2.87 0.0
Use 0 0.0 0 0.0
Disposal 1.6e+10 0.4 1.12e+03 0.5
Total (for first life) 4.18e+12 100 2.26e+05 100
End of life potential -3.92e+12 -2.08e+05
Table 6: Energy use and CO2 footprint for silicon nitride tower
Phase Energy (J) Energy (%) CO2 (kg) CO2 (%)
Material 9.75e+12 99.8 3.9e+05 99.7
Manufacture 0 0.0 0 0.0
Transport 4.05e+07 0.0 2.87 0.0
http://c/Users/jmcho8/Downloads/silicon%20nitride.doc%23MaterialPhasehttp://c/Users/jmcho8/Downloads/silicon%20nitride.doc%23MaterialPhasehttp://c/Users/jmcho8/Downloads/silicon%20nitride.doc%23MaterialPhase -
8/13/2019 Material Design Report
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Use 0 0.0 0 0.0
Disposal 1.6e+10 0.2 1.12e+03 0.3
Total (for first life) 9.76e+12 100 3.91e+05 100
End of life potential -9.51e+12 -3.73e+05
Table 7: Comparison of energy use for top 3 tower materials
Top 3 tower materialsTotal energy use (For material, manufacturing,
transportation and use phases)
Silicon carbide 5.90E+12
Alumina 4.16E+12
Silicon nitride 9.74E+12
Figure 5: Energy use comparison of top 3 tower materials
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Table 8: Energy use and CO2 footprint for cast Al-alloys blades
Phase Energy (J) Energy (%) CO2 (kg) CO2 (%)
Material 7.03e+12 94.5 4.23e+05 93.2
Manufacture 4.05e+11 5.5 3.04e+04 6.7
Transport 1.77e+07 0.0 1.26 0.0
Use 0 0.0 0 0.0
Disposal 7e+09 0.1 490 0.1
Total (for first life) 7.44e+12 100 4.54e+05 100
End of life potential -6.92e+12 -4.16e+05
Table 9: Energy use and CO2 footprint for age-hardening wrought Al-alloys blades
Phase Energy (J) Energy (%) CO2 (kg) CO2 (%)
Material 7.29e+12 95.0 4.48e+05 94.0
Manufacture 3.76e+11 4.9 2.81e+04 5.9
Transport 1.77e+07 0.0 1.26 0.0
Use 0 0.0 0 0.0
Disposal 7e+09 0.1 490 0.1
Total (for first life) 7.67e+12 100 4.76e+05 100
End of life potential -7.18e+12 -4.4e+05
Table 10: Energy use and CO2 footprint for non-age-hardening wrought Al-alloys blades
Phase Energy (J) Energy (%) CO2 (kg) CO2 (%)
Material 7.36e+12 95.5 4.6e+05 94.6
Manufacture 3.4e+11 4.4 2.55e+04 5.3
Transport 1.77e+07 0.0 1.26 0.0
Use 0 0.0 0 0.0
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Disposal 7e+09 0.1 490 0.1
Total (for first life) 7.71e+12 100 4.86e+05 100
End of life potential -7.25e+12 -4.52e+05
Table 11: Comparison of energy use for top 3 blades materials
Top 3 blades materialsTotal energy use (For material, manufacturing,
transportation and use phases)
Cast Al-alloys 7.43E+12
Age-hardening wrought Al-alloys 7.66E+12
Non-age-hardening wrought Al-alloys 7.70E+12
Figure 6: Energy use comparison of top 3 blades materials
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
Materials for
blades
100% virgin material
energy use (J)
100% recycled material
energy use (J)Energy difference (J)
Cast Al-alloys 7.03e+12 8.79e+11 6.15E+12
Age-hardening
wrought Al-alloys7.29e+12 1.23e+12 6.06E+12
Non-age-hardening wrought
Al-alloys
7.36e+12 1.24e+12 6.12E+12
Table 12: Material energy comparison between 100% virgin material and 100% recycled material for
blades
As the materials for tower are all technical ceramics which cannot be recycled, there is no
comparison between 100% virgin and 100% recycled material. From the table above, it is obvious that
production of 100% recycled materials use less energy than production of 100% virgin materials for
turbine blades.
Deficiency in Eco-Audit Process
1. Legal requirements are not stated in the process2. Environmental related cost is excluded in the Eco-Audit process3. Choices such as transport type are limited for the Eco-Audit functions4. Database combination in a single analysis is not available
Conclusion
The best material to construct wind turbine tower will be silicon carbide. Although the totalenergy use from production to use of silicon carbide is more than alumina, its price is less than alumina
and silicon nitride while its density is less than alumina. Moreover, it has a relatively high yield strength.
Its yield strength and elastic modulus is higher than the minimum design stress and elastic modulus
obtained from the optimum geometry. Therefore silicon carbide is more suitable than alumina and silicon
nitride as material for turbine tower. Other than that, the best material for wind turbine blades will be cast
Al-alloys. This is because the total energy use from production to use of cast Al-alloys is less than age-
hardening wrought Al-alloys and non-age-hardening wrought Al-alloys. It has a similar price and density
as the other two materials while having the highest elastic modulus among them. Thus, cast Al-alloys is
the best choice among the three materials. Both of the selected tower and turbine materials are functional
in temperature of -40oC to 40
oC, high durability towards effect of marine environment and UV radiation.
The tower material selected has excellent durability towards salt water.
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ENG1050Design of Materials ReportName: Chong Jie Mee Student ID: 24731706Demonstrator: Mr. Vahdat Vahedi Lab session: Thursday 11am-1pm
References
W.D. Callister, Materials Science and Engineering, an Introduction, 7th edition: Chapter 23. MaterialsSelection and Design Considerations; Chapter 24. Economic, Environmental, and Societal Issues in
Materials Science and Engineering
CES Edupack 2012
Webcorr 2013,Different Types of Corrosion - Mechanisms, Recognition & Prevention.Retrieved October
17, 2013, from http://www.corrosionclinic.com/different_types_of_corrosion.htm
Materials Information Technology Challenges with Wind Turbine Technology,
http://grantadesign.com/news/news/reports/wind.shtml.
M.F. Ashby, Materials Selection in Mechanical Design, Vols I and II, Pergamon, Oxford, 1992.
F. Karpat 2013, A Virtual Tool for Minimum Cost Design of a Wind Turbine Tower with RingStiffeners,Energies, vol. 6, pp. 3822-3840.
http://www.corrosionclinic.com/different_types_of_corrosion.htmhttp://grantadesign.com/news/news/reports/wind.shtmlhttp://grantadesign.com/news/news/reports/wind.shtmlhttp://www.corrosionclinic.com/different_types_of_corrosion.htm