selecting materials product function interdependence mechanical properties physical properties...

Selecting Materials

Product function interdependence

Mechanical properties Physical properties Families of materials Materials first screening

When do we select specific materials?

?

FormulationFormulation

Customer Needs

Customer requirementsImportance weightsEng. characteristicsHouse of QualityEng. Design Spec’s

Concept DesignConcept Design

Abstract embodiment Physical principlesMaterialGeometry Configuration

DesignConfiguration

Design

arrangement of parts/features(i.e. shaping materials)

Therefore, let’s examine…

Formulation

Detail Design

Parametric Design

Configuration Design

Concept Designmaterials manufacturing

processes

Interdependence - compatibility

Material Properties

ManufacturingProcesses

compatiblematerials & processes

Interdependence - capability

ManufacturingProcesses

ProductGeometry

capable processesfor the geometry

Product function is interdependent

Material Properties

ManufacturingProcesses

ProductGeometry

ProductFunction

Tekniker-ILL neutron monochromator

Example

Design a support for the electric motor

Example

Tekniker-ILL neutron monochromator

Example

Tekniker-ILL neutron monochromator

Example

Tekniker-ILL neutron monochromator

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 to physical phenomena other than mechanical

forces …(e.g. such as heat, electricity, radiation)

Physical properties

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 ?

Mechanical properties

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 reduction

dimensionless

Hardness resists surface indentation

Brinell No. MPa (ksi)

Corrosion resistance

resists chemicals, oxidation

galvanic series activity number

Fundamental properties

Characteristic Behavior Property Units

Fatigue resistance endures many load cycles endurance limit MPa (Mpsi)

Conductivity (heat, electric)

conducts, insulates

thermal conductivity electrical conductivity

(Btu/hr) / (F-ft), Mhos

Creep resistance time dependent stretching

creep strength MPa (ksi)

Impact resistance shock, impact loads Charpy energy N-m, (ft-lbs)

Density (mass) Density (weight)

heavy, light mass density weight density

kg/m3, (slugs/ft3) N/m3, (lbs/ft3)

Temperature tolerance softens, or melts easily melting point degrees C, F

Material families / sub-families

CeramicsMetals Plastics Composites

Materials

Elastomers

Thermosets

Thermoplastics

Non-ferrous

Ferrous

Sub-family

Family(Ashby)

Material sub-families / classes

Metals

Materials

FerrousSub-family

Family

Classes

Cast ironCarbon steelAlloy steelStainless steel

Metals

Non-ferrousFerrous

Metals

aluminum brass bronze copper lead magnesium nickeltin titanium tungstenzinc

cast ironcarbon steelalloy steelstainless steel

ElastomersThermosetsThermoplastics

Polymers

butylfluorocarbonneoprenenitrilepolysulfiderubbersilicone

alkydepoxymelaminephenolicpolyesterurethane

ABSacetalacrylicnylonpolycarbonatepolyethylenepolypropylenepolystyrenevinyl

Natural and synthetic rubbersPolymers

Polymers

Cross-linking

No chemical reaction

Ceramics

Ceramics

aluminaberylliadiamondmagnesiasilicon carbidesilicon nitridezirconia

Composites

carbon fiberceramic matrixglass fiberKevlarmetal matrix

Composites

Composites

Carbon fiber Style 282 bidirectional.

Araldite epoxy resin with HY956 additive.

Manufacturing process

Composites

Ossur Flexwalk

College Park Foot

Otto Bock Advantage

Pie protésico dinámico2004

Pie protésico dinámico2005

Composites

MarlonShirley

OssurCheetaFlex-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

Property profiles by family

Materials selection

prospective materials and processes

screening

rating

rejected materials and processes

best material(s) and processes

functional?manufacturable?

relativeperformance?

feasiblematerials and

processes

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?

Screening: Materials first approach

Application Information

1. Applied loadsmagnitudecyclic nature (steady, fatigue)rate (slow, impact)duration (creep)

2. Ambient conditionstemperaturemoisturesunlightchemical liquids/vapors

3. Safety4. Cost

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

Materials selection

prospective materials and processes

screening

rating

rejected materials and processes

best material(s) and processes

functional?manufacturable?

relativeperformance?

feasiblematerials and

processes

Rating: Material indices

Given the same cost/volume… which is stronger?

index = Strength/cost

Given the same cost/volume… which is stiffer?

index = Young’s modulus/cost

AshbyChart

How can we use it?

Summary

Product function interdependence

Mechanical properties Physical properties Families, sub, classes of

materials Ashby charts Materials first approach Process first approach