Engineering 11
Materials
Selection
Bruce Mayer, PE
Licensed Electrical & Mechanical Engineer
BMayer@ChabotCollege.edu
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Materials Selection at Config
Customer Needs
Formulation
Concept Design
Abstract
embodiment?
Physical principles
Material
Geometry
Engineering-11: Engineering Design
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Customer
requirements
Importance weights
Eng. characteristics
House of Quality
Eng. Design Spec’s
Configuration
Design
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Matls & Manuf  Closely Linked
Problem Formulation
Concept Design
materials
Configuration Design
manufacturing
processes
Parametric Design
Detail Design
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Matls & Manuf  Closely Linked
Material
Properties
Manufacturing
Processes
Engineering-11: Engineering Design
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 e.g.; Ceramics can
NOT be WELDED
COMPATIBLE
materials & processes
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Matls & Manuf  Closely Linked
 e.g.; CAST Parts
can NOT have
SHARP Corners
Manufacturing
Processes
Engineering-11: Engineering Design
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CAPABLE Processes
for the geometry
Product
Geometry
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Matl↔Manf↔Geom  Function
Material
Properties
Product
Function
Manufacturing
Processes
Engineering-11: Engineering Design
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Product
Geometry
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Properties of Solid Materials
 Mechanical: Characteristics of materials
displayed when Forces or Moments are
applied to them.
 Physical: Characteristics of materials that
relate to the interaction of materials with
various forms of energy.
 Chemical: Material characteristics that
relate to the Material’s electron structure.
 Dimensional: Size, shape, and finish
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Material Properties
Chemical
Composition
Microstructure
Phases
Grain Size
Corrosion
Crystallinity
Molecular Weight
Flammability
Physical
Melting Point
Thermal
Magnetic
Electrical
Optical
Acoustic
Gravimetric
Mechanical
Dimensional
Tensile properties
Toughness
Ductility
Fatigue
Hardness
Standard Shapes
Standard Sizes
Surface Texture
Stability
Mfg. Tolerances
Creep
Compression
 One More ≡ $COST, $COST, $COST
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Solid-Materials Family Tree
Materials
Metals
Ferrous
Non-ferrous
Plastics
Ceramics
Composites
Thermoplastics
Thermosets
Sub-family
Elastomers
See Also ENGR45
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Solid-Materials Taxonomy
Materials
Metals
Ferrous
Family
Sub-family
Cast iron
Carbon steel
Alloy steel
Stainless steel
Engineering-11: Engineering Design
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Classes
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Metals Family Tree
Metals
Ferrous (Mostly Iron)
cast iron
carbon steel
alloy steel
stainless steel
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Non-ferrous
aluminum
brass
bronze
copper
lead
magnesium
nickel
tin
titanium
tungsten
zinc
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Polymer (Plastics) Family Tree
Polymers
Thermoplastics
ABS
acetal
acrylic
nylon
polycarbonate
polyethylene
polypropylene
polystyrene
vinyl
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Thermosets
alkyd
epoxy
melamine
phenolic
polyester
urethane
Elastomers
butyl
fluorocarbon
neoprene
nitrile
polysulfide
rubber
silicone
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Ceramics & Composites Trees
Ceramics
alumina
beryllia
diamond
magnesia
Silicates
Silica
carbide
Nitride
Oxide
zirconia
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Composites
carbon fiber
ceramic matrix
glass fiber
Kevlar fiber
metal matrix
polymer matrix
Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Material Family Comparison
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Materials Selection Strategy
prospective
materials and processes
functional?
manufacturable?
screening
rejected
materials and processes
feasible
materials and
processes
relative
performance?
rating
best
material(s) and processes
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Materials Selection
 The designer of any product, other than
software, must be part of the material
selection process.
 Only occasionally will the exact grade of
material be specified by the customer.
• Even then the designer
must UNDERSTAND
the material to be able
to design the product.
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Decisions, Decisions!
 So many materials, so much
information.
• How do we decide?
• How do we even begin to choose?
– Metals are the DEFAULT as they have the
widest variety of Manufacturing Processes
 First we need to look at the function of
the product
• Use PRODUCT ANALYSIS
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Product Analysis
 Just what it says – analyze the
product!
•
•
•
•
•
What does it do?
How does it do it?
Where does it do it?
Who uses it?
What should it cost?
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Case Study  BiCycle
 What is the function of a bike – obvious?
 How does the function depend on the type
of bike?
• Racing
• Touring
• Mountain
• Commuter
• Child’s
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Case Study  BiCycle (2)
 How is it made to be easily maintained?
 What should it look like (colors etc.)?
 What should it cost?
• Child’s Bike VS. Professional Racing Bike
 How has it been made comfortable to
ride?
 How do the mechanical parts work and
interact?
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Component or System?
 1st problem is…….
Is a BiCycle one component or a
system of components working
together?
 e.g.; a one-piece Bracket is a
component, a Cordless Screwdriver is a
system.
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
System Analysis
 When we analyze
a system we need
to break the system
down into individual
components and
then analyze each
one for the best Matl.
 CordLess
A Nice EXPLODED-View
ScrewDriver
(Assembly) Drawing
BreakDown
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
System Analysis  BiCycle
 The bike breaks down (Not Literally,
we hope) into various parts:
•
•
•
•
•
Frame & Forks
Wheels & Brakes
Seat & Peddles
Gears & Chain
Safety (reflectors)
• etc. 
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
System Analysis  BiCycle
 Now need to look at the following
for each part:
• Requirements (mechanical,
ergonomic, aesthetic etc.)
• Function
• How many are going to be made?
• What manufacturing methods are we
going to use?
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Manufacturing InterDependency
 YES!...We have to actually MAKE it!
 This is a key question which has a
HUGE influence on materials selection.
 e.g., what materials could we use for
the FRAME?
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Frame Material Candidates
 Steel
• Strong, stiff, HEAVY, Inexpensive,
Easy to Join
 Aluminum
• WEAKER, lighter, MORE EXPENSIVE
than steel, Hard to Join
 Composite (CFRP)
• strong, stiff, very light,
but MOST EXPENSIVE
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Bike Frame
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Frame Joint
Detail
 A Critical
Manufacturing
Process Detail
• Weld?
• Braze?
• Shrink Fit?
• Other?
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Where do I find Materials data?
 Textbooks
 Databooks
 Manufacturer’s
literature
 Internet Sites
• Current
Default
– Most
DataBooks
are OnLine
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Textbooks
 Good for general information
 Some have tables of properties
 Not good for detailed specifications
and properties.
 A useful starting
point
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Databooks
 One of the quickest sources of
detailed information.
 Usually contain grades and
specifications as well as properties.
 Small and perfectly formed –
pocketbooks
 Easy to navigate around
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Manufacturer’s literature
 Variable in quality and usefulness.
 Often only cover their products.
 Usually do not compare materials.
 Can be biased.
 Good for final selection before
ordering.
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
InterNet Sites
 Can be a real minefield.
 Lots of poorly presented
information.
 Google searches bring up lots of
SuperFluous info.
 Hard to find technical information.
 Best to use non-commercial sites.
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
MatWeb.com is VERY Good for Props
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Materials Selection Charts
 Allow easy visualization of
properties
 Show lots of different materials
 Can be ‘drilled down’ to specifics
 Show balances of properties
e.g. strength vs cost
 Ideal for a first ‘rough cut’ selection
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
TradeOff Weight & Stiffness
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Modulus - Density Chart
 Modulus spans 5 orders of magnitude
• 0.01 GPa for foams to 1000 GPa for
diamond
 The charts therefore use logarithmic
scales, where twice the distance means
ten times the property value.
 This makes it possible to show the full
range on one chart,
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
TradeOff Weight & Strength
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
TradeOff Insulation & Expansion
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Summary  Matls Selection
1. Think about the design from
ergonomic and functional viewpoint.
2. Decide on the materials to be used.
3. Choose suitable manufacturing
processes that are also economic

Steps 2 & 3 may be iterative. Don’t
forget the …………… NextSlide
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Bigger Picture (don’t forget)
 Is the product
PERFORMANCE
driven or COST
driven?
• This makes a
huge difference
when choosing
materials.
– Kid’s bike vs.
Racing bike
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Manufacturing Priority
 Although we usually choose
materials FIRST sometimes
it is the SHAPE and
PROCESS which is the
limiting factor.
• e.g.; Complex HiVacuum
Chambers almost always
must be WELDED to form
GasTight Seals
– Limits Materials Selection
to METALS
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Summary  Materials Selection







Product function interdependence
Mechanical properties
Physical properties
Families, sub, classes of materials
TradeOff (Ashby) charts
Materials first approach
Process first approach
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
All Done for Today
Another
Ashby
Chart
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
Engineering 11
Appendix
Bruce Mayer, PE
Registered Electrical & Mechanical Engineer
BMayer@ChabotCollege.edu
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt
What is an Ashby Chart?
 It’s a form of a picture that’s worth
well more than a 1000 words for
any engineering designer. Named for
Prof. M. F .Ashby, this is a tool that’s less
widely used than it should be.
 The chart involves plotting “clouds” on a
2-axis plot, with different variables on
each axis. Sounds simple, but the impact
doesn’t hit you till you actually see them,
as in this example from Granta above:
Engineering-11: Engineering Design
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Bruce Mayer, PE
BMayer@ChabotCollege.edu • ENGR-11_Lec-08_Chp5_Materials_Selection.ppt