Selecting Materials Product function interdependence Mechanical properties Physical properties Families of materials Materials first screening

When do we select specific materials? ? Formulation Customer Needs Customer requirements Importance weights Eng. characteristics House of Quality Eng. Design Spec’s Concept Design Abstract embodiment Physical principles Material Geometry Configuration Design arrangement of parts/features (i.e. shaping materials)

Therefore, let’s examine… Formulation Detail Design Parametric Design Configuration Design Concept Design materials manufacturing processes

Interdependence - compatibility Material Properties Manufacturing Processes compatible materials & processes

Interdependence - capability Manufacturing Processes Product Geometry capable processes for the geometry

Product function is interdependent Material Properties Manufacturing Processes Product Geometry Product Function

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 ? brittle Strength = stress at failure =  (failure) elastic plastic ductile ?

Mechanical properties

Fundamental properties

Material families / sub-families CeramicsMetalsPlasticsComposites Materials Elastomers Thermosets Thermoplastics Non-ferrous Ferrous Sub-family Family (Ashby)

Material sub-families / classes Metals Materials Ferrous Sub-family Family Classes Cast iron Carbon steel Alloy steel Stainless steel

Metals Non-ferrousFerrous Metals aluminum brass bronze copper lead magnesium nickel tin titanium tungsten zinc cast iron carbon steel alloy steel stainless steel

Elastomers Thermosets Thermoplastics Polymers butyl fluorocarbon neoprene nitrile polysulfide rubber silicone alkyd epoxy melamine phenolic polyester urethane ABS acetal acrylic nylon polycarbonate polyethylene polypropylene polystyrene vinyl Natural and synthetic rubbers Polymers

Cross-linking No chemical reaction

Ceramics alumina beryllia diamond magnesia silicon carbide silicon nitride zirconia

Composites carbon fiber ceramic matrix glass fiber Kevlar metal matrix 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 dinámico 2004 Pie protésico dinámico 2005

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

Property profiles by family

Materials selection prospective materials and processes screening rating rejected materials and processes best material(s) and processes functional? manufacturable? relative performance? feasible materials 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 loads magnitude cyclic nature (steady, fatigue) rate (slow, impact) duration (creep) 2. Ambient conditions temperature moisture sunlight chemical liquids/vapors 3. Safety 4. Cost

Screening: Manufact process first approach Part Information 1. Production volume 2. Part size (overall) 3. 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 screening rating rejected materials and processes best material(s) and processes functional? manufacturable? relative performance? feasible materials 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

Ashby Chart 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