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BK50A2700 Selection Criteria of Structural Materials. Lesson 3 2014. Systematic material selection process. Lesson 3 2014. The goal of this lesson.
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BK50A2700 Selection Criteria of Structural Materials Lesson3 2014
Systematic material selection process Lesson 3 2014
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.
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.
DEVELOPMENT PHASES OF MATERIAL TECHNOLOGY 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
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
Gasturbineapplication NOT ONLY THE OPTIONAL MATERIAL OF A SINGLE COMPONENT …BUT ALSO THE OPTIMIZED MATERIALS IN THE CONSTRUCTION
CONSTRUCTIONAL MATERIAL SELECTION SHAPED OBJECTS MADE OF DIFFERENT MATERIALS PRODUCT’S MATERIAL SELECTION CONSTRUCTION TECHNICAL SPESIFICATIONS PRODUCTION TRIALS TYPICAL AND EASY GEOMETRIES AND SHAPES FOR EACH MATERIAL GROUP PROTOTYPES/ PROTOTYPE TESTING MATERIAL SELECTION PHASES USER FRIENDLY GEOMETRY PRODUCT AND PRODUCTION DEVELOPMENT 3D-MODELING OF THE PRODUCT ESTHETIC VALUES OF THE SHAPE COMMERCIALIZED PRODUCTS “PROTOTYPE” “IN REAL USE” “VISION”
MATERIAL SELECTION CRITERIA HUMIDITY ABSORPTION WEAR AGEING CORROSION TEMPERATURE LOAD BEARING CAPACITY STIFFNESS AND RIGIDITY WEAR RESISTANCE ENERGY ABSORPTION CONDITIONS AND ENVIRONMENT FUNCTION MATERIAL SELECTION PRODUCTION AND MANUFACTURING COSTS RAW MATERIAL COSTS PRODUCTION COSTS SERVICE AND MAINTENANCE COSTS QUALITY COSTS RECYCLING AND REUSE COSTS DISPOSAL COSTS LCC/LCA WELDABILITY CASTABILITY MACHINABILITY FORMABILITY COATABILITY
MATERIAL SELECTION IS A COMPROMISE MANUFACTURING PRODUCTION TECHNOLOGIES DIMENSIONS AND GEOMETRY OF THE PRODUCT MATERIAL SELECTION OVERLAPPING AREA FOR FINDING COMPROMISES TO ENABLE REASONABLE MATERIAL SELECTION
SEQUENTAL AND CONCURRENT ENGINEERING PRODUCT’S PERFORMANCE MATERIAL SELECTION PRODUCTION DESIGN RAPID PROTOTYPING MODELING DESIGN PRODUCTION MATERIAL SELECTION (DATABASES)
SYSTEMATIC MATERIAL SELECTION PROCESS FUNCTIONS CONDITIONS PRODUCTION COSTS LIMITS DUE TO LOAD BEARING CAPACITY FUNCTIONAL LIMITS FAILURE MATRIX ANALYSIS OF THE SUB-ASSEMBLIES 1. ELABORATION OF THE REQUIREMENTS PROFILE ECO-EFFICIENCY CLEAN AND GREEN TECHNOLOGY COST-EFFECTIVENESS RELIABILITY BASED DESIGN 2. DECISION ABOUT THE SELECTION STRATEGY TYPICAL AND COMMON SOLUTIONS STANDARDIZED SOLUTIONS AVAILABLE BULK SIZES AND ALLOYS 3. PRE-SELECTION OF POSSIBLE MATERIALS CONCRETE NUMERICAL DATA MATERIALS’ PROPERTY MAPS FUNCTION INDEX FOUR- AND MULTIFIELD ANALYSES NEW OPTIONS BASED ON HEAT TREATMENTS AND SURFACE COATINGS 4. ELABORATION OF THE MATERIALS’ PROPERTY PROFILE 5. INTEGRATION OF THE REQUIREMENT AND THE PROPERTY PROFILES VALUE ANALYSIS COSTS COMPARISONS LCA /LCC FINAL SELECTION 6. MONITORING AND FEEDBACK
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.
F A T I G U E M A T E R I A L P A I R SPUR GEAR 1 SPUR GEAR 2 W E A R
Specified properties of steel alloys POWER TRANSMISSION CAPACITY BASED ON THE ALLOWED BENDING STRESS AT THE TOOTH ROOT ”FATIGUE” Specified properties of ceramics M A T E R I A L P A I R REQUIREMENTS MAIN MATERIAL PROPERTIES Specified properties of composites SPUR GEAR 1 Specified properties of HP-polymers OTHER REQUIREMENTS BASED ON THE ”FUNCTIONAL CONDITIONS” Specified properties of different steel alloys SPUR GEAR 2 POWER TRANSMISSION CAPACITY BASED ON THE ALLOWED SURFACE PRESSURE ON THE TOOTH CONTACT AREA ”WEAR” Specified properties of ceramics REQUIREMENTS MAIN MATERIAL PROPERTIES Specified properties of composites Specified properties of HP-polymers
RECOGNITION OF THE MAIN SELECTION CRITERION • Is there the risk of too low load bearing capacity? Dimensioning criteria Functional limits Plastic durability Load bearing capacity Stability No initial cracks Plastic deformation due to reversed loading Fatigue failure Possible initial cracks Corrosion fatigue Brittle fracture
Is there the risk that functional limits will be exceeded, though there is no risk of exceeding the load bearing capacity? Dimensioning criteria Functional limits Local deformation Bending Load bearing capacity E.g. too extensive bending, local deformations of vibrations might prevent the use of the constructions though no failure wont take place. Input (in pulse) x (t) Output (response) u (t) Vibration Time t
ULTIMATE TENSILE STRENGTH FOUR-FIELD ANALYSIS MIN. OPERATING TEMPERATURE MAX. OPERATING TEMPERATURE IMPACT STRENGTH COBWEB- ANALYSIS MODULUS OF ELASTICITY 1/DENSITY YELD STRENGTH HARDNESS FATIGUE STRENGTH IMPACT STRENGTH
MATERIAL SELECTION CUBIC INTENDED CORRECTION FLEXIBLE JOINT FORCE TRANSMISSION SUPPORT OTHER FUNCTION OTHER ACTION CHANGE OF MATERIAL CHANGE OF COMPONENT DEFELOPMENT OF THE COMPONENT MAIN FUNCTION OF THE COMPONENT WEAR DUCTILE FRACTURE OTHER FAILURE FATIGUE FAILURE BRITTLE FRACTURE THE CELL, WHICH DESCRIBES THE MEANING OF MATERIAL CHANGE WHEN THE PURPOSE IS TO AVOID FATIGUE FAILURE IN A FORCE TRANSMISSION COMPONENT FAILURE MODE OF THE COMPONENT
SPECIAL FEATURES IN SELECTING CONSTRUCTIONAL MATERIALS SELECTION CRITERIA BASED ON CORROSION RESISTANCE SYSTEMATIC SELECTION PROCESS GREEN TECHNOLOGY SPECIAL FEATURES IN SELECTING CONSTRUCTIONAL MATERIALS SELECTION CRITERIA BASED ON RELIABILITY SELECTION CRITERIA BASED ON STRENGTH SELECTION CRITERIA BASED ON WEAR RESISTANCE SELECTION CRITERIA BASED ON MANUFACTURABILITY
WEB-BASED TOOLS FOR MATERIAL SELECTION • http://www.format.mwn.de/Werkstoffe/statisch/werkstoffsuche/werkstoffsuche_de.jsp
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