HANDOUT 1 - Materials in Design

Question 1

what are the current drivers for development in structural materials?

Answer 1

transport: lightweighting vehicles, engine efficiency
energy: wind turbines, nuclear power

life sciences: biomaterials - implants, artificial bond; medical devices

sustainability: reduction in waste and packaging, greater recycling
sports: high performance products (F1, racing yachts, athletics)

Question 2

What functional materials does material engineering include?

Answer 2

Optical

Semiconductor

electronic

magnetic

Question 3

Give an a example of a “functional” material that overlaps with “structural”:

Answer 3

• Speed of a hard disk is limited by inertia, vibration etc.
• superconducting magnetics produce fields which can break the magnet.
• overhead power lines are limited by strength and thermal expansion.

Question 4

Give the four design requirements required for designing a product.

Answer 4

Function

• support loads on support, store mechanical energy
• conduct heat or electricity efficiently, prevent heat loss

Constraints

• allowable dimesnions, shape restrictions
• allowable deflection
• resist corrosion or oxidation
• limits in weight or cost
• ease of manufacture and recyclability

Objectives

-minimum weight or cost or environmental impact

Free variables(parameters designers can adjust)

• some dimensions
• material(s) selected
• manufacturing route

Question 5

Give the specification for the design requirement of a bicycle.

Answer 5

Function:

-support rider weight between the wheel axles, allow comfortable and efficient pedalling action.

Constraints:

• Geometric limits on spac between axles and height.
• specified stiffness: deflection under loading
• Resist failure - no plastic deformation
• resist corrosion from water
• weight or cost

Objectives:

• Minimise cost ( standard bikes ) or weight ( performance bikes)

Free variables:

• cross-sectional shape and dimensions of structural members in frame.
• materials and manufacturing processes

Question 6

Give design-limiting material properties.

Answer 6

Question 7

How does manufacturing place limits on a design?

Answer 7

• significant contribution to product cost
• processability of material? ( size&shape; metling point, ductility)
• ease of joining components?

Question 8

How are materials being evaluated for their environmental impact?

Answer 8

Possible “eco-indicators”:

• “embodied energy” for CO₂ output per kg, in material production.
• recyclability
• toxicity, NO_x production etc.

Question 9

Draw the product life-cycle.

Answer 9