BK50A2700 Selection Criteria of Structural Materials

Lesson 32014

Systematic material selection process

Lesson 32014

The goal of this lesson

Our goal is, that after this lesson, students are able to implement the systematic material selection process by collecting the product’s requirement list and by finding he corresponding material properties to finally select the optimized constructional material of the product.

Motivation

The importance of proper material selection is increasing, because:

New, better materials are and will be available year after year

Material properties and materials’ quality are improving all the time

The demands of better cost-effectiveness in engineering requires optimized material selection

Environmental aspects and green technology has become more important in material selection

Etc.

1750 1800 1850 1900 1950 2000 DECADE

DEVELOPMENT OF CEMENT

DEVELOPMENT OF THE DIFFERENT FORMS OF SILICON

DEVELOPMENT OF STEELS

DEVELOPMENT OF POLYMERS

DEVELOPMENT OF CARBON FIBRES

DEVELOPMENT OF CARBON NANOTUBES

DEVELOPMENT OF GRAPHENES

DEVELOPMENT PHASES OF MATERIAL TECHNOLOGY

What’s the difference between “materials” and

“constructional materials”?

NOT ONLY THE MATERIAL ITSELF……BUT ALSO ITS APPLICATIONS!

NOT ONLY THE OPTIONAL MATERIALS OF A SINGLE COMPONENT…

…BUT ALSO THE CRITICAL MATERIAL PAIRS IN THE CONSTRUCTION

NOT ONLY THE OPTIONAL MATERIAL OF A SINGLE COMPONENT

…BUT ALSO THE OPTIMIZED MATERIALS IN THE CONSTRUCTION

Gas turbine application

SHAPED OBJECTS MADE OF DIFFERENT

MATERIALS

TYPICAL AND EASY GEOMETRIES AND SHAPES

FOR EACH MATERIAL GROUP

MATERIAL SELECTION PHASES

USER FRIENDLY GEOMETRY

ESTHETIC VALUES OF THE SHAPE

PRODUCT’S MATERIAL

SELECTION

PROTOTYPES/ PROTOTYPE

TESTING

3D-MODELING OF THE

PRODUCT

CONSTRUCTIONAL MATERIAL SELECTION

CONSTRUCTION TECHNICAL

SPESIFICATIONSPRODUCTION TRIALS

PRODUCT AND PRODUCTION

DEVELOPMENT

COMMERCIALIZED PRODUCTS

“VISION” “PROTOTYPE” “IN REAL USE”

General criteria of material selection

HUMIDITY ABSORPTION

WEAR

AGEING

CORROSION

TEMPERATURE

WELDABILITY

CASTABILITY

MACHINABILITY

FORMABILITY

COATABILITY

LOAD BEARING CAPACITY

STIFFNESS AND RIGIDITY

WEAR RESISTANCE

ENERGY ABSORPTION

RAW MATERIAL COSTS

PRODUCTION COSTS

SERVICE AND

MAINTENANCE COSTS

QUALITY COSTS

RECYCLING AND REUSE COSTS

DISPOSAL COSTS

LCC/LCA

MATERIAL SELECTION

MATERIAL SELECTION CRITERIA

OVERLAPPING AREA FOR FINDING COMPROMISES TO ENABLE REASONABLE MATERIAL SELECTION

MANUFACTURING PRODUCTION

TECHNOLOGIES

DIMENSIONS AND GEOMETRY OF THE PRODUCT

MATERIAL SELECTION

MATERIAL SELECTION IS A COMPROMISE

DESIGN PRODUCTIONMODELING

RAPID PROTOTYPING

MATERIAL SELECTION (DATABASES)

DESIGNPRODUCT’S PERFORMANCE

MATERIAL SELECTION

PRODUCTION

SEQUENTAL AND CONCURRENT ENGINEERING

The systematic process

1. ELABORATION OF THE REQUIREMENTS PROFILE

2. DECISION ABOUT THE SELECTION STRATEGY

3. PRE-SELECTION OF POSSIBLE MATERIALS

4. ELABORATION OF THE MATERIALS’ PROPERTY PROFILE

5. INTEGRATION OF THE REQUIREMENT AND THE PROPERTY PROFILES

6. MONITORING AND FEEDBACK

LIMITS DUE TO LOAD BEARING CAPACITYFUNCTIONAL LIMITSFAILURE MATRIXANALYSIS OF THE SUB-ASSEMBLIES

ECO-EFFICIENCY CLEAN AND GREEN TECHNOLOGYCOST-EFFECTIVENESSRELIABILITY BASED DESIGN

TYPICAL AND COMMON SOLUTIONSSTANDARDIZED SOLUTIONSAVAILABLE BULK SIZES AND ALLOYS

CONCRETE NUMERICAL DATAMATERIALS’ PROPERTY MAPSFUNCTION INDEXFOUR- AND MULTIFIELD ANALYSESNEW OPTIONS BASED ON HEAT TREATMENTS AND SURFACE COATINGS

VALUE ANALYSISCOSTS COMPARISONSLCA /LCC

FUNCTIONS

CONDITIONS

PRODUCTION

COSTS

FINAL SELECTION

SYSTEMATIC MATERIAL SELECTION PROCESS

FUNCTIONAL REQUIREMENTS

FUNCTION: Should remain rigid and stiff Enough load bearing capacity is

required against pulsating loading under varying temperature

ENVIRONMENTAL CONDITIONS: Good adhesive and abrasive load

bearing capacity is required MANUFACTURING AND

PRODUCTION Should be cost-effective in mass

production COSTS

Eco-efficiency throughout the lifetime is required

CORRESPONDING MATERIAL PROPERTIES

FUNCTION: Hardness, modulus of elasticity, thermal

coefficient, shear modulus Fatigue strength, thermal strength

ENVIRONMENTAL CONDITIONS: Hardness, friction co-efficient

MANUFACTURING AND PRODUCTION Melting temperature, shrinking rate, wall

thickness COSTS

Recycling rate, MI- and MIPS-values

Objective numerical values are needed for optional materials.

Principal examples

SURFACE PRESSURE

REQUIREMENT MAIN MATERIAL PROPERTY

Adhesive wear resistance LOW FRICTION COEFFICIENT BETWEEN GEARS

Abrasive wear resistance HARDNESS DIFFERENCE BETWEEN GEARSFORMABILITYSURFACE PROPERTIES

Fatigue wear resistance FATIGUE STRENGTHSURFACE PROPERTIES

Tribochemical wear resistance

CHEMICAL RESISTANCE

Local surface compression load bearing capacity

MODULUS OF ELASTICITY AND POISSON’S COEFFICIENT

ROOT STRENGTH

REQUIREMENT MAIN MATERIAL PROPERTY

Dynamic load bearing capacity

FATIGUE STRENGTHSURFACE PROPERTIES CRACK SENSITIVITY

Torque transmission capacity

STIFFNESSBENDING STRENGTH AND DUCTILITYDUCTILE CORE AND HARD SURFACE

SPUR GEAR 1

SPUR GEAR 2

MATERIAL

PAIR

FATIGUE

WEAR

Specified properties of steel alloys

Specified properties of ceramics

Specified properties of composites

Specified properties of ceramics

Specified properties of composites

Specified properties of HP-polymers

SPUR GEAR 1

SPUR GEAR 2

MATERIAL

PAIR

POWER TRANSMISSION

CAPACITY BASED ON THE ALLOWED BENDING STRESS

AT THE TOOTH ROOT

”FATIGUE”

POWER TRANSMISSION

CAPACITY BASED ON THE ALLOWED

SURFACE PRESSURE ON THE TOOTH CONTACT

AREA ”WEAR”

OTHER REQUIREMENTS BASED ON THE”FUNCTIONAL CONDITIONS”

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Specified properties of HP-polymers

Specified properties of different steel alloys

Some tools for finding the relevant material properties

RECOGNITION OF THE MAIN SELECTION CRITERION

Is there the risk of too low load bearing capacity?

Load bearing capacity

Functional limits

StabilityPlastic durability

Plastic deformation due to reversed loading

Possible initial cracks

No initial cracks

Dimensioning criteria

Corrosion fatigueBrittle fracture

Fatigue failure

Is there the risk that functional limits will be exceeded, though there is no risk of exceeding the load bearing capacity?

Dimensioning criteria

Load bearing capacity

Functional limits

Bending Local deformation

Vibration

Input (in pulse) x (t) Output (response) u (t)

Time t

E.g. too extensive bending, local deformations of vibrations might prevent the use of the constructions though no failure wont take place.

MIN. OPERATING TEMPERATURE

MAX. OPERATING TEMPERATURE

IMPACT STRENGTH

1/DENSITY YELD STRENGTH

HARDNESS

IMPACT STRENGTH

FATIGUE STRENGTH

ULTIMATE TENSILE STRENGTH

MODULUS OF ELASTICITY

FOUR-FIELDANALYSIS

COBWEB-ANALYSIS

TWO TYPES OF FAILURE MODE MATRIXES

Component: Ball bearing

Part Failure mode

Outer ring Abrasive wearDeformation

Inner ring Abrasive wear

Cage Corrosion

Balls Abrasive wear

Component material: 100Cr5

Failure mode

Material property

Abrasive wear

Hardness

Deformation

Yeld strengthCompression strength

Corrosion Chemical corrosion reistance

1 2

FAILURE MODE OF THE COMPONENT

OTHER ACTION

CHANGE OF MATERIAL

SUPPORT

FLEXIBLE JOINT FORCE TRANSMISSION

OTHER FUNCTION

INTENDED CORRECTION

THE CELL, WHICH DESCRIBES THE MEANING OF MATERIAL CHANGE WHEN THE PURPOSE IS TO AVOID FATIGUE FAILURE IN A FORCE TRANSMISSION COMPONENT

CHANGE OF COMPONENT

DEFELOPMENT OF THE COMPONENT

DUCTILE FRACTUREWEAR

FATIGUE FAILUREOTHER FAILURE

BRITTLE FRACTURE

MAIN FUNCTION OF THE COMPONENT

MATERIAL SELECTION CUBIC

SPECIAL FEATURES IN SELECTING

CONSTRUCTIONAL MATERIALS

GREEN TECHNOLOGY

SYSTEMATIC SELECTION PROCESS

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SELECTION C

RITERIA BASED ON

WEAR RESISTANCE

SELECTION CRITERIA BASED ON

MANUFACTURABILITY

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SELECTION CRITERIA BASED ON CORROSION RESISTANCE

SPECIAL FEATURES IN SELECTING CONSTRUCTIONAL MATERIALS

http://www.format.mwn.de/Werkstoffe/statisch/werkstoffsuche/werkstoffsuche_de.jsp

WEB-BASED TOOLS FOR MATERIAL SELECTION

CONCLUSIONS… Typically the material database includes only a list of material’s

properties To be able to fully utilize material databases the detailed requirements’

profile is needed to find the necessary numerical values for specific material properties

Usually the user should have enough knowledge and experience to be able to make compromises between different material properties and to make the final selection of the material

There might be some ”subjectivity” in commercial databases Databases made for specific application areas give some suggestions of

materials and their cost and lifetime data, but usually quite strict limitations are given to the ”results” validity.

“The DeZURIK Elastomer, Polymer and Metal Selection Guide is designed to be used as a guide in selecting the most cost effective valve material. It should only be used as a starting point. There are a variety of conditions which can affect the material chosen. Careful consideration must be given to temperature, the presence of other materials in the solution and the concentration of the media before the material can be selected.”

Detailed requirements are needed to find detailed material properties!

Remember the content of our repetititon lectures…What type of strength is needed?

Strength in elevated temperature, in corrosive environments…

Varying loads: pulsating, reversed…Compression, tensile, bending, share…

What type of corrosion is affecting?Erosion, pitting, galvanic corrosion etc.The only solution is NOT “stainless steels “There are different types of stainless steels available

What type of wear is affecting?Abrasive, adhesive, tribochemical or fatigue wear?The only solution is NOT to find harder materials