Manufacturing technical objects

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Manufacturingtechnical objects
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Materials

• To decide which materials are suitable for making
  technical objects (made of one or more materials)
  manufacturers must first determine the
  stress/possible deformations the objects will be
  exposed to.

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A constraint describes the effect of external
forces on a material

• (p. 387 of your textbook)
• Main types of constraints
• Compression (squeezing/crushing)
• Tension (stretching)
• Torsion (twisting)
• Deflection (bending)
• Shearing (cutting)

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Three types of material deformation (p.387)

• Elastic temporary change in shape
• Plastic permanent change in shape
• Fracture death of the material (breaks)

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Properties (p.388-389)

• Mechanical properties how a material reacts when
  subjected to one or more constraints.
• Hardness ability to resist damage/scratches
• Elasticity ability to return to original shape
• Resilience resist shocks without breaking
• Ductility can be stretched without breaking
• Malleability can be flattened without breaking
• Stiffness ability to retain shape when subjected
  to various constraints

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Other properties

• Resistance to corrosion (resist effects of
  corrosive substances like water and salts which
  cause the formation of rust)
• Electrical conductivity ( ability to carry an
  electrical current)
• Thermal conductivity (ability to transmit heat)

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Degradation and Protection (p. 389- 390)

• Degradation of a material decline of its
  properties due to the effects of the surrounding
  environment
• Protection of a material application of
  procedures that prevent or delay degradation

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In class work

• P. 418-419
• Questions 1 to 6
• Assignment
• Using everyday household items attempt to build a
  support for books. See how many books your
  support can...support. Work in pairs but hand in
  individual reports. Your report should make
  reference to the terminology seen on material and
  have the standard lab report format.