Learning Outcomes
Review
Introduction
Materials for Mechanical Design
Part 1: 3 Types of Material Properties
Properties of
Materials
Elasticity Constants
Physical Properties
Professor Dr. Mazharul Islam
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
2 / 44
Bibliography
Department of Mechanical and Production Engineering
Ahsanullah University of Science and Technology, Dhaka, Bangladesh
Licensed under the Creative Commons Attribution-ShareAlike 4.0 International License
(https://creativecommons.org/licenses/by-sa/4.0/)
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Learning Outcomes for the Class Session
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
3 / 44
Bibliography
After duly participating in this class session and studying the related
contents on the accompanying online course site, the students will be
expected to
classify engineering materials;
define the elasticity constants;
explain the key physical properties of the engineering materials;
explain the key chemical properties of the engineering materials;
explain the key mechanical properties of the engineering materials;
and
address the variability of materials properties data in design works.
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Brain Storming
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
5 / 44
Bibliography
How the engineering materials
can be classified?
Common Types
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
6 / 44
Bibliography
Ductile Vs Brittle
Metal Vs Non-Metal
Ferrous Vs Non-Ferrous
Material Families and Classes [1, Table 2-5, pp. 81-82]
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
7 / 44
Bibliography
Metals
Ceramics
Glasses
Polymers
Elastomers
Hybrids
Composites
Foams
Natural Materials
"Materials Data Book" from Cambridge University
Engineering Department, 2011
Learning Outcomes
Review
Available at http://teaching.eng.cam.ac.uk/sites/teaching.
eng.cam.ac.uk/files/Documents/Databooks/MATERIALS%
20DATABOOK%20(2011)%20version%20for%20Moodle.pdf
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
8 / 44
Bibliography
"V. CLASSIFICATION AND
APPLICATIONS OF
ENGINEERING MATERIALS"
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Brain Storming
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
9 / 44
Bibliography
Which properties of materials
are important for mechanical
design?
3 Types of Properties
Learning Outcomes
Review
Physical Properties
Introduction
Properties of
Materials
Elasticity Constants
Chemical Properties
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
10 / 44
Bibliography
Mechanical Properties
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Elasticity Constants
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
11 / 44
Bibliography
Poisson’s Ratio (µ)
Young’s Modulus or Modulus of Elasticity (E)
Shear Modulus or Modulus of Rigidity (G)
Bulk Modulus (K)
Flexural Modulus
Poisson’s Ratio (µ or ν)
−Lateral Strain
−ϵL
=
=ν
Axial Strain
ϵa
(adopted from Mott and Tang [4])
"When a material is subjected to a tensile strain, there is simultaneous
shortening of the cross-sectional dimensions perpendicular to the
direction of the tensile strain" [4]
"The ratio of the shortening strain to the tensile strain is called Poisson’s
ratio" [4]
Typical values based on [4]
Poisson′ s ratio =
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Cast Iron: 0.25 to 0.27
Steel: 0.27 to 0.30
Aluminum and Titanium: 0.30 to 0.33
Post-Assessment
Summary
12 / 44
Bibliography
Please refer to Figure 2-4 of [4, p. 36] for more insights.
Young’s Modulus or Modulus of Elasticity (E)
Learning Outcomes
Review
E=
Introduction
stress
σ
=
strain
ϵ
(Eq. (2-1) from Mott and Tang [4])
Properties of
Materials
Elasticity Constants
Derived from the Hooke’s Law [2]
Physical Properties
Unit is GPa
Chemical Properties
Please consult Table 4.1 of [2] for the typical values of E for some of
common engineering materials
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
13 / 44
Bibliography
Shear Modulus or Modulus of Rigidity (G)
Learning Outcomes
Review
G=
Introduction
Shear Stress
τ
=
Shear Strain
ϕ
(as per [2, p. 94])
Properties of
Materials
Elasticity Constants
Based on experimental investigations [2]
Physical Properties
Unit is GPa
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
14 / 44
Bibliography
Please consult Table 4.2 of [2] for the typical values of G for some of
common engineering materials
Bulk Modulus (K)
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
15 / 44
Bibliography
K=
Direct Stress
σ
=
Volumetric Strain
δV /V
(as per [2, p. 112])
"When a body is subjected to three mutually perpendicular stress, or
equal intensity, then the ratio of the direct stress to the corresponding
volumetric strain is known as bulk modulus" [2]
Bulk Modulus (K)
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
16 / 44
Bibliography
K=
Direct Stress
σ
=
Volumetric Strain
δV /V
(as per [2, p. 112])
"When a body is subjected to three mutually perpendicular stress, or
equal intensity, then the ratio of the direct stress to the corresponding
volumetric strain is known as bulk modulus" [2]
Flexural Modulus or Modulus of Elasticity in Flexure[4,
p. 37]
Learning Outcomes
Review
"another stiffness measure often reported, particularly for plastics" [4]
Introduction
"a specimen of a material is loaded as a beam in flexure (bending) with
data taken and plotted for load versus deflection" [4]
Properties of
Materials
Elasticity Constants
"The ratio of stress to strain is a measure of the flexural modulus " [4]
Physical Properties
"the stress pattern in the specimen is a combination of tension and
compression "
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
17 / 44
Bibliography
Relationships between Elastic Constants
Learning Outcomes
Review
Introduction
K=
E
3(1 − 2µ)
(as per [2, p. 112])
G=
E
2(1 + µ)
(as per [2, p. 112])
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
18 / 44
Bibliography
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Physical Properties
Melting (of Softening) Temperature
Learning Outcomes
Review
Introduction
Density
Properties of
Materials
Elasticity Constants
Coefficient of Thermal Expansion
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
19 / 44
Bibliography
Thermal Conductivity
Electrical Resistivity
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Chemical Properties 1
Heat of Combusion
Learning Outcomes
Review
Chemical Stability
Introduction
Properties of
Materials
Elasticity Constants
Preferred Oxidation State(s)
Physical Properties
Chemical Properties
Mechanical
Properties
Ability to Corrode
Variability of
Material Properties
Data
Post-Assessment
Summary
20 / 44
Bibliography
1
Adopted from
https://www.samaterials.com/physical-and-chemical-properties.html
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Mechanical Properties [2, 3]
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
21 / 44
Bibliography
Strength
Stiffness
Elasticity
Plasticity
Ductility
Brittleness
Malleability
Toughness
Machinability
Resilience
Creep
Fatigue
Hardness
Tensile Test
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
22 / 44
Bibliography
"Strength, elastic, and ductility properties for metals, plastics, and
other types of materials are usually determined from a tensile test"
[4]
"a sample of the material, typically in the form of a round or flat
bar, is clamped between jaws and pulled slowly until it breaks in
tension" [4]
Please refer to "Section 2-1 Material Strength and Stiffness"
in the Textbook [1]
Tensile Strength (Su )
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
"The peak of the stress-strain curve is considered the ultimate
tensile strength (Su )" [4]
"sometimes called the ultimate strength or simply tensile strength"
[4]
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
23 / 44
Bibliography
(Eq. 1.11 [4])
Yield Strength (sy )
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
24 / 44
Bibliography
"That portion of the stress-strain diagram where there is a large
increase in strain with little or no increase in stress" [4]
"The property indicates that the material has, in fact, yielded or
elongated plastically, permanently, and to a large degree" [4]
Shear Strength (sy s or su s)
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
"Both the yield strength and the ultimate strength in shear (sy s and
su s, respectively) are important properties" [4]
"Unfortunately, these values are seldom reported" [4]
"We will use the following estimates" [4]
sys = sy /2 = 0.50sy = yield strength in shear
(Eq. (2-3) from Mott and Tang [4])
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
25 / 44
Bibliography
sus = 0.75su = ultimate strength in shear
(Eq. (2-3) from Mott and Tang [4])
Fatigue Strength or Endurance Strength (sy s or su s)
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
26 / 44
Bibliography
"Parts subjected to repeated applications of loads or to stress
conditions that vary with time over several thousands or millions of
cycles fail because of the phenomenon of fatigue" [4]
"Materials are tested under controlled cycle loading to determine
their ability to resist such repeated loads" [4]
"The resulting data are reported as the fatigue strength" [4]
"also called the endurance strength of the material" [4]
Stiffness or Rigidity
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
27 / 44
Bibliography
"It is the ability of the material to resist deformation under stress"
[2]
"The modulus of elasticity is the measure of stiffness" [2]
Elasticity
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
28 / 44
Bibliography
"the property of a material to regain its original shape after
deformation when the external forces are removed" [2]
"desirable for materials in tools and machines" [2]
"steel is more elastic than rubber " [2]
Plasticity
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
29 / 44
Bibliography
"property of a material which retains the deformation produced
under load permanently " [2]
"necessary for forging, in stamping images on coins and in
ornamental works" [2]
Ductility
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
30 / 44
Bibliography
"degree to which a material will deform before ultimate fracture" [4]
"When ductile materials are used in machine members, impending
failure is detected easily, and sudden failure is unlikely" [4]
"ductile materials normally resist the repeated loads on machine
elements better than brittle materials" [4]
"The usual measure of ductility is percent elongation of the material
after fracture in a standard tensile test" [4]
Lf − LO
× 100%
LO
(Eq. (2-1) from Mott and Tang [4])
Percent Elongation =
Brittleness
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
31 / 44
Bibliography
"The opposite of ductility is brittleness" [4]
"shows negligible plastic deformation before fracture takes place" [3]
"Brittle material fail by sudden fracture" [3]
Example: Cast Iron
Malleability
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
32 / 44
Bibliography
"a special case of ductility which permits the material to be rolled
or hammered into thin sheets" [2]
"The malleable materials commonly used in engineering practice (in
order of diminishing malleability) are lead, soft steel, wrought iron,
copper and aluminium" [2]
Toughness
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
33 / 44
Bibliography
"The property of the material to resist fracture due to high impact
loads like hammer blows" [2]
"desirable in parts subjected to shock and impact loads" [2]
"Tough materials have the ability to bend, twist or stretch before
failure takes place" [3]
"Modulus of toughness is the total area under stress-strain curve in
tension test" [3]
Machinability
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
34 / 44
Bibliography
"the property of a material which refers to a relative case with
which a material can be cut" [2]
"reported in comparative terms, relating the performance of a given
material with some standard" [4]
"brass can be easily machined than steel" [2]
Resilience
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
35 / 44
Bibliography
"ability of the material to absorb energy when deformed elastically
and to release this energy when unloaded" [3]
"A resilient material absorbs energy within the elastic range without
any permanent deformation" [3]
"essential for spring materials" [3]
"measured by a quantity called modulus of resilience" [3]
"represented by area under stress-strain curve from origin to elastic
limit point" [3]
Creep
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
36 / 44
Bibliography
"When a part is subjected to a constant stress at high temperature
for a long period of time, it will undergo a slow and permanent
deformation called creep" [2]
"considered in designing internal combustion engines, boilers and
turbines" [2]
Fatigue
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
37 / 44
Bibliography
"When a material is subjected to repeated stresses, it fails at
stresses below the yield point stresses" [2]
"Such type of failure of a material is known as fatigue" [2]
"The failure is caused by means of a progressive crack formation
which is usually fine and microscopic size" [2]
"considered in designing shafts, connecting rods, springs, gears,
etc." [2]
Hardness
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
38 / 44
Bibliography
"defined as the resistance of the material to penetration or
permanent deformation" [3]
"an important property in selection of materials for parts which rub
on one another such as pinion and gear, cam and follower, rail and
wheel and parts of the ball bearings" [3]
"four primary methods of measuring hardness - Brinell hardness
test, Rockwell hardness test, Vickers hardness test and Shore
scleroscope" [3]
Please read Section "2-4 Hardness" of [1] for more information
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Variability of Material Properties Data
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
39 / 44
Bibliography
"As the designer, you must carefully judge the reliability of the data
that you use" [4]
"you should evaluate the reliability of the final product by
considering the actual variations in material properties, the
manufacturing considerations that may affect performance, and the
interactions of various components with each other" [4]
Please read Section "2-2 The Statistical Significance of Material
Properties" of [1]
"Materials Data Book" from Cambridge University
Engineering Department, 2011
Learning Outcomes
Available at http://teaching.eng.cam.ac.uk/sites/teaching.
eng.cam.ac.uk/files/Documents/Databooks/MATERIALS%
20DATABOOK%20(2011)%20version%20for%20Moodle.pdf
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
40 / 44
Bibliography
"It must be realised that many material properties
(such as toughness) vary between wide depending on
composition and previous treatment. Any final design
should be based on manufacturers’ or suppliers’ data
for the material in question, and not on the data
given here."
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Lessons Learned in Today’s Class Session
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
41 / 44
Bibliography
What are the key lessons you have
learned today?
1
Learning Outcomes
2
Review
3
Introduction
4
Properties of Materials
5
Elasticity Constants
6
Physical Properties
7
Chemical Properties
8
Mechanical Properties
9
Variability of Material Properties Data
10
Post-Assessment
11
Summary
Summary
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
42 / 44
Bibliography
Classification of engineering materials;
Physical properties of the engineering materials;
Chemical properties of the engineering materials;
Mechanical properties of the engineering materials; and
Variability of materials properties data in design works.
Summary of the Mechanical Properties
Strength
(yield/ultimate/shear/fatigue)
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Stiffness or Rigidity (Young’s
Modulus/Flexural Modulus)
Elasticity (elastic regions)
Machinability (comparative
terms)
Plasticity (plastic regions/Flexural
Modulus)
Resilience (modulus of resilience)
Chemical Properties
Ductility (Percent Elongation)
Mechanical
Properties
Brittleness (fracture point)
Variability of
Material Properties
Data
Malleability (compressive stress at
breaking point)
Post-Assessment
Summary
43 / 44
Bibliography
Toughness (Modulus of
Toughness)
Creep (creep strain)
Fatigue (fatigue strength)
Hardness (BHN/HB)
References
I
Learning Outcomes
Review
Introduction
Properties of
Materials
Elasticity Constants
Physical Properties
Chemical Properties
Mechanical
Properties
Variability of
Material Properties
Data
Post-Assessment
Summary
44 / 44
Bibliography
[1] R. G. Budynas and J. K. Nisbett, Shigley’s MECHANICAL
ENGINEERING DESIGN. McGraw-Hill Education (India) Private Limited,
eleventh e ed., 2021.
[2] R. S. Khurmi and J. K. Gupta, A Textbook of Machine Design. S. Chand
Publishing, low priced students’ paperback edition ed., 2019.
[3] V. B. Bhandari, Design of MACHINE ELEMENTS. McGraw-Hill
Education (India) Private Limited, silver jubilee ed., 2021.
[4] R. L. Mott and J. Tang, Machine Elements in Mechanical Design.
Pearson India, 2020.