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Selecting Materials. Product function interdependence Mechanical properties Physical properties Families of materials Materials first screening. Customer Needs. Formulation. Customer requirements Importance weights Eng. characteristics House of Quality Eng. Design Spec’s .
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Selecting Materials • Product function interdependence • Mechanical properties • Physical properties • Families of materials • Materials first screening
Customer Needs Formulation Customer requirements Importance weights Eng. characteristics House of Quality Eng. Design Spec’s Concept Design Abstract embodiment Physical principles Material Geometry ? Configuration Design When do we select specific materials? arrangement of parts/features (i.e. shaping materials)
Formulation Concept Design manufacturing processes materials Configuration Design Parametric Design Detail Design Therefore, let’s examine…
Interdependence - compatibility Material Properties Manufacturing Processes compatible materials & processes
Interdependence - capability capable processes for the geometry Manufacturing Processes Product Geometry
Product function is interdependent Material Properties Product Function Manufacturing Processes Product Geometry
Example Design a support for the electric motor Tekniker-ILL neutron monochromator
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 • Physical properties quantities that characterize the behavior of a material in response to physical phenomena other than mechanical forces …(e.g. such as heat, electricity, radiation)
ductile ? brittle elastic plastic Mechanical properties stiffness ? Strength = stress at failure = (failure)
Materials Metals Plastics Ceramics Composites Family (Ashby) Ferrous Thermoplastics Thermosets Non-ferrous Sub-family Elastomers Material families / sub-families
Family Sub-family Classes Material sub-families / classes Materials Metals Ferrous Cast iron Carbon steel Alloy steel Stainless steel
Metals Metals Ferrous Non-ferrous cast iron carbon steel alloy steel stainless steel aluminum brass bronze copper lead magnesium nickel tin titanium tungsten zinc
Polymers Thermoplastics Thermosets Elastomers ABS acetal acrylic nylon polycarbonate polyethylene polypropylene polystyrene vinyl alkyd epoxy melamine phenolic polyester urethane butyl fluorocarbon neoprene nitrile polysulfide rubber silicone Natural and synthetic rubbers Polymers
Polymers No chemical reaction Cross-linking
Ceramics alumina beryllia diamond magnesia silicon carbide silicon nitride zirconia Ceramics
Composites carbon fiber ceramic matrix glass fiber Kevlar metal matrix Composites
Composites Manufacturing process Carbon fiber Style 282 bidirectional. Araldite epoxy resin with HY956 additive.
Composites College Park Foot Otto Bock Advantage Ossur Flexwalk Pie protésico dinámico2004 Pie protésico dinámico2005
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
Materials selection prospective materials and processes rejected materials and processes functional? manufacturable? screening feasible materials and processes relative performance? rating best material(s) 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 • Applied loads magnitude cyclic nature (steady, fatigue) rate (slow, impact) duration (creep) • Ambient conditions temperature moisture sunlight chemical liquids/vapors • Safety • Cost
Screening: Manufact process first approach • Part Information • Production volume • Part size (overall) • Shape capability (features) • boss/depression 1D • boss/depression >1D • holes • undercuts (internal/external) • uniform walls • cross sections (uniform /regular) • rotational symmetry • captured cavities
Materials selection prospective materials and processes rejected materials and processes functional? manufacturable? screening feasible materials and processes relative performance? rating best material(s) 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