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When do we select specific materials?

?

Formulation

Customer Needs

Customer requirements

Importance weightsEng. characteristics

House of Quality

Eng. Design SpecsConcept Design

Abstract embodiment

Physical principlesMaterial

Geometry Configuration

Design

arrangement of parts/features

(i.e. shaping materials)

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Therefore, lets examine

Formulation

Detail Design

Parametric Design

Configuration Design

Concept Design

materials manufacturingprocesses

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Interdependence - compatibility

Material

Properties

Manufacturing

Processescompatible

materials & processes

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Interdependence - capability

Manufacturing

Processes

Product

Geometry

capable processes

for the geometry

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Product function is interdependent

Material

Properties

Manufacturing

Processes

Product

Geometry

Product

Function

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Example

Tekniker-ILL neutron monochromator

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Example

Tekniker-ILL neutron monochromator

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Material properties

Mechanical properties

quantities that characterize the

behavior of a material in response to

external, or applied forces

quantities that characterize the

behavior of a material in response tophysical phenomena other than mechanical forces(e.g. such as heat, electricity, radiation)

Physical properties

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Mechanical properties

stiffness ?

E

F

F

LL L

A

brittle

Strength = stress at failure = (failure)

A/F

stress

L

LLstrain

yS

utS

elastic plastic

y f

ductile ?

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Mechanical properties

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Fundamental properties

Characteristic Behavior Property Units

Strength strong, weak ultimate strength MPa (ksi)

Elastic strength elastic then plastic yield strength MPa (ksi)

Stiffness flexible, rigid modulus of elasticity MPa (Mpsi)

Ductility draws, forms easily% elongation,

% area reductiondimensionless

Hardness resists surface

indentation

Brinell No. MPa (ksi)

Corrosion resistance

resists chemicals,

oxidation

galvanic series activity

number

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Material families / sub-families

CeramicsMetals Plastics Composites

Materials

Elastomers

Thermosets

Thermoplastics

Non-ferrous

Ferrous

Sub-family

Family(Ashby)

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Material sub-families / classes

Metals

Materials

FerrousSub-family

Family

Classes

Cast ironCarbon steel

Alloy steel

Stainless steel

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Metals

Non-ferrousFerrous

Metals

aluminumbrass

bronze

copper

lead

magnesiumnickel

tin

titanium

tungsten

zinc

cast ironcarbon steel

alloy steel

stainless steel

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Polymers

Cross-linking

No chemical reaction

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Ceramics

Ceramics

alumina

beryllia

diamondmagnesia

silicon carbide

silicon nitride

zirconia

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Composites

carbon fiber

ceramic

matrixglass fiber

Kevlar

metal

matrix

Composites

http://www2.dupont.com/Kevlar/en_US/index.htmlhttp://www2.dupont.com/Kevlar/en_US/index.html

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Composites

Carbon fiber Style 282 bidirectional.

Araldite epoxy resin with HY956 additive.

Manufacturing process

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Composites

Ossur Flexwalk

College Park Foot

Otto Bock Advantage

Pie protsico dinmico

2004

Pie protsico dinmico

2005

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Composites

Marlon

Shirley

Ossur

Cheeta

Flex-Foot

Cameron

Clapp

Otto Bock

C-Leg

Date of birth: April 21, 1978

Hometown: Thatcher, Utah

Current Home:San Diego, CA

Date of birth: Sep 15, 1986

http://www.youtube.com/watch?v=G3YkEv6KjdIhttp://www.youtube.com/watch?v=G3YkEv6KjdIhttp://www.youtube.com/watch?v=G3YkEv6KjdIhttp://www.youtube.com/watch?v=G3YkEv6KjdIhttp://www.youtube.com/watch?v=G3YkEv6KjdIhttp://www.youtube.com/watch?v=_WknmsmTJSU&feature=relatedhttp://video.google.com/videoplay?docid=-933936669450038099

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Property profiles by family

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Materials selection

prospectivematerials and processes

screening

rating

rejected

materials and processes

best

material(s) and processes

functional?

manufacturable?

relative

performance?

feasible

materials and

processes

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Screening: How do we choose a material?

Product function depends upon

material, manufacturing process, geometry

We have to consider all three

Do we select a few feasible materials first

then select the specific mfg process?

or

Do we select a few feasible mfg processes

then select the specific material?

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Screening: Materials first approach

Application Information

1. Applied loadsmagnitudecyclic nature (steady, fatigue)

rate (slow, impact)duration (creep)

2. Ambient conditionstemperature

moisturesunlightchemical liquids/vapors

3. Safety4. Cost

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Screening: Manufact process first approach

Part Information

1. Production volume2. Part size (overall)

3. Shape capability (features)boss/depression 1Dboss/depression >1Dholesundercuts (internal/external)uniform wallscross sections (uniform /regular)rotational symmetrycaptured cavities

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Materials selection

prospectivematerials and processes

screening

rating

rejected

materials and processes

best

material(s) and processes

functional?

manufacturable?

relative

performance?

feasible

materials and

processes

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Rating: Material indices

Given the same cost/volume which is stronger?

index = Strength/cost

Given the same cost/volume which is stiffer?

index = Youngs modulus/cost

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AshbyChart

How canwe useit?

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Summary

Product function interdependence

Mechanical properties

Physical properties

Families, sub, classes of materials Ashby charts

Materials first approach

Process first approach