Topic 4 - pt.1 Flashcards

(41 cards)

1
Q

list the mechanical properties

A
  • tensile and compressive strength
  • stiffness
  • toughness
  • ductility
  • elasticity
  • plasticity
  • Young’s Modulus
  • stress
  • strain
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2
Q

list the aesthetic characteristics

A
  • taste
  • smell
  • appearance
  • texture
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3
Q

list the properties of smart materials

A
  • piezo electricity
  • shape memory
  • photocromocity
  • magneto-rheostatic
  • electro-rheostatic
  • thermoelectricity
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4
Q

electrical resistivity

A

a material’s ability to conduct or resist electricity

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5
Q

thermal conductivity

A

a measure of how fast heat moves through the material

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6
Q

thermal expansion

A

the degree to which a material increases in its dimensions due to heat

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7
Q

hardness

A

the resistance of a material to scratching or penetration

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8
Q

tensile strength

A

ability of a material to withstand pulling forces
- important for selecting materials for ropes and cables

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9
Q

compressive strength

A

ability of a material to withstand being pushed or squashed
- important for selecting materials for structures e.g. pillars

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10
Q

stiffness

A

the resistance of an elastic body to deflection by an applied force

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11
Q

toughness

A

the ability of a material to plastically deform without fracturing –> a material’s resistance to fracture when stressed

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12
Q

plasticity

A

ability of a material to be changed in shape permanently by external blows or pressure without cracking or breaking

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13
Q

stress

A

the force per unit area of a material
- normally determined by applying a tensile force to material

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14
Q

strain

A

after a tensile force is applied to a material it’s expected to be elongated

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15
Q

Young’s Modulus

A

measure of stiffness of an elastic material –> ratio of stress along an axis to the strain

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16
Q

photo-chromocity

A

material that can be described as having a reversible change of colour when exposed to light

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17
Q

thermoelectricity

A

generated by a device that converts heat and the temp difference between materials into electricity

18
Q

magneto-rheostatic

A

fluids which can experience a dramatic change in consistency when exposed to a magnetic or electric field
- e.g. thick fluid to solid really quickly

19
Q

piezo electricity

A

squeeze or pressure giving off a small electrical discharge

20
Q

shape memory

A

metals that have a rearrangement of the molecules in the material due to changes in temp

21
Q

composite materials

A

materials made from two or more materials with different physical or chemical properties –> when combined produce a material w different characteristics from original
- this is done to make materials stronger, lighter, or less expensive

22
Q

advantages of composite materials

A
  • high strength to weight ratio
  • high tensile strength
  • when weaving it can produce a prettier look
  • (weaving) different materials can be chosen to make it more strong or stiff
23
Q

disadvantage of composites

A
  • very expensive
  • requires specific manufacturing facilities
  • weak when compressed or squashed
  • air bubbles will cause weak spots and reduce overall impact
  • difficult or can’t be recycled
24
Q

plywood

A
  • manufactured from an uneven number of plys
  • needed where high quality, high strength, and large sheet material is required
  • resistant to cracking, breaking, shrinkage, and twisting
  • can be used as an engineering material for architecture or marine environments
25
laminated glass
- consists of a sandwich of glass-polymer(PVB)-glass stuck with heat and pressure in autoclave - when broken the PVB layer holds the pieces of glass together (safer) - used for car windshield - the fracture produces spider-web pattern crack
26
laminar composites
- laminates of different materials joined together in sandwich structure - a layer of thin bidirectional fibers/metal sheets held apart by a lightweight core
27
weaving
forms fabric by interlacing long threads passing in one direction with others at a right angle to them (bidirectional)
28
pultrusion
continuous moulding process making sure fibers are saturated with a liquid polymer resin and carefully formed and pulled through a heated die to form a part
29
lamination
assembling individual sheets of materials into a multilayered material or component with heat and pressure
30
spray-up
carried out on open mould where both the resin and reinforcements are sprayed directly onto mould
31
how is concrete made
- sand, concrete, aggregate, and water to form a fluid mass that is easily moulded --> becomes hard and solid after drying - aim is to increase strength
32
how is engineered wood made
- binding or fixing strands, particles of fibers, veneers of boards of wood together with adhesive - used for medium-density fireboard, plywood, chipboard
33
how is plywood made
- sheet material that is manufactured from thin layers or "plies" of wood veneers that are glued together with adjacent layers - used for wall panelling, flooring, and furniture
34
how is particleboard made
- (chipboard) is an engineered wood product made from wood chips, sawmill shavings or sawdust, and synthetic resin
35
what is kevlar
- woven into a cloth which combined with polyester resin can be moulded into different shapes - can also be woven into fabric cloth to protect wearer - has high strength-to-weight ratio --> 5 times stronger than steel - used for body protection (bulletproof vest), helmets, sports equipment (skis), racquets, sails for windsurfing
36
how is carbon-reinforced plastic (GRP) made
- made from plastic and fibreglass - can easily be moulded into 3D shapes, versatile, good strength-to-weight ratio - used for boat hulls, canoes, car body panels, chemical storage tanks, and train canopies
37
how is laminated veneer lumber (LVL) made
- uses multiple layers of thin wood assembled with adhesives - used for headers, beams, rim boards, edge-forming material
38
SP: one-off
- used when only one for a few specialist items is required --> produces a single product - advantages: unique and high-quality products are made, workers are motivated and take pride in their work - disadvantages: labour intensive so prices are high, production can take a long time and expensive from using specialist tools
39
SP: batch production
- a set number of items to be produced - advantages: unit costs are lower since large numbers are made, offers curtomers variety and choice, materials can be bought in bulk so cheaper - disadvantages: workers less motivated since work is repetitive, goods have to be stored until they're sold which can be expensive
40
SP: mass and continuous flow
- Mass: production of large amounts of standardized products on production lines --> high rates of production per worker - Continuous Flow: PM used to manufacture/produce/process materials without interruption - advantages: labour costs low, materials can be purchased in large quantities so cheaper, large number of goods are produced - disadvantages: machinery expensive to buy and set up, workers not motivated, not flexible bc production line is difficult to adapt, production process has to be stopped when repairs are made
41
SP: mass customization
- a CIM system that manufactures products to individual customer orders - mass customization uses techniques from mass production; its output is based on core components