Flashcards
As DT
Flashcards do conjunto (53)
- 1Define DuctilityThe ability of a material to change shape (deform) usually by stretching along its length.
- 2Define ElasticityThe ability of a material to absorb force and flex in different directions, returning to its original position.
- 3Define plasticityThe ability of a material to be change in shape permanently.
- 4Define strengthThe ability of a material to stand up to forces being applied without it bending, breaking, shattering or deforming in any way.
- 5Define tensile strengthThe ability of a material to stretch without breaking or snapping.
- 6Define MalleabilityThe ability of a material to be reshaped in all directions without cracking
- 7Define ToughnessA characteristic of a material that does not break or shatter when receiving a blow or under a sudden shock.
- 8Define HardnessThe ability of a material to resist scratching, wear and tear and indentation.
- 9Define brittlenessThe tendency of a material to fracture under stress
- 10Define conductivityThe ability of a material to conduct electricity.
- 11List 3 ferrous metalso mild steel
o carbon steel
o cast iron - 12List 3 non ferrous metalso aluminium
o copper
o zinc - 13List 3 alloys an what they are made up ofBrass(Copper and Zinc)
Duraluminium (Copper, aluminium and managanese)
Stainless steel (steel, chromium,nickel) - 14explain what is meant by a composite• Two or more materials combined by bonding
• The resulting material often has improved mechanical, functional and aesthetic properties
• Tend to have excellent strength-to-weight ratios - 15advantages of GRPsCan be as strong as steel, excellent strength to weight ratio, very resistant to corrosion.
- 16Disadvantages of GRPsCan be brittle (shatter easily), can be prone to osmosis (where water can seep into the material. Safety can also be an issue (the resin and catalyst can give off toxic fumes, cam be a skin irritant (gloves must be ward).
- 17Advantages of Carbon fibreMuch stronger than GRP. Can be as stronger than steel, excellent strength to weight ratio, very resistant to corrosion. Can take tensile and compressive loads.
- 18Disadvantages of Carbon fibreExpensive
- 19Define thermoceramics• Advanced ceramic material that have an internal structure that makes them extremely hard and very stable at very high temperatures.
• Produced by combining ceramic and metallic powders through sintering. - 20Advantages of ThermoceramicsVery stable and strong at high temperatures.
- 21Disadvantages of thermoceramicsCan be brittle and break if dropped, imperfections in the ceramic material can lead to cracking or breakage. Costs can be significantly higher than traditional materials.
- 22Uses of thermoceramicsPlaces where there is a need for stability and strength at very high temperatures e.g. turbine blades in jet engines, turbo charges used in racing cars.
- 23Uses of Carbon FibreHigh performance structural applications – aircraft, sports equipment, racing car manufacture.
- 24Uses of GRPsBoat building, fishing rods, sports equipment.
- 25Label the parts used in injection moulding
- 26Label the parts of a centre lathe
- 27Label the wood lathe
- 28Advantages of Nuts and boltsCan be removed and reapplied an infinite number of times (temporary)
Strong mechanical joint - 29What are the Disadvantages of nuts and bolts?Prone to vibration
same size nut and bolt required - 30What are the Advantages of snap rivets?Good strong joint
- 31What are the Disadvantages of snap rivets?acess to both sides is required
- 32What are the Advantages of pop rivetsCan be applied from one side
- 33Disadvantages of pop rivetsWeak compared to snap rivets
- 34whats are the Uses of gears?Change direction of rotary motion
change spindle speeds
transmt motion through 90 degrees - 35Describe the function of Spur gearsSimple gearboxes
speeds can be inceased or decreased
Direction of rotation can be changed - 36Describe the function of Bevel and mitre gearsCan have shafts at 90 degrees
differetn sizes of gears can change speeds
Hand drills - 37Describe the function of Worm and wheel gearsTransmit force and motion through 90 degrees
Reduction in rotational speeds possible
Used in food mixers - 38Describe the function of a rack and pinion gearUsed to change rotary motion into linear motion
Used in pillar drills
steering mechanisms in cars - 39Describe the characteristics of flat followerLots of friction
can not follow hollow contours - 40Draw a flat follower
- 41Describe the characteristics of a knife followerProvides the most accurate conversion of movement
can be used to follow hollow contours - 42Describe the characteristics of roller followersleast friction
most expensive
can not follow hollow contours - 43Draw a knife edge follower
- 44Draw a Roller follower
- 45Describe the characteristics of a pear shaped camUsed to control inlet and outlet valves in engines.
Symettrcally shaped so that rise and fall times are identical - 46Describe the characteristics of a eccentric or circular camSmooth rise and fall
used in fuel pumps
constant accelaration and retardation
simplest type of cam as based on an off centre circular disc - 47Describe the characteristics of a heart shaped camSymmetrical
generate continous motion
used in sewing machines - 48Describe the characteristics of snail camsGenerate output with unform acceleration and retardation
- 49Draw a Pear shaped cam
- 50Draw a snail cam
- 51Draw a heart shaped cam
- 52Draw an eccentric or circular cam
- 53What is the function of a Cam and FollowerTo transfer rotary motion into linear motion
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- FlashCards sobre As DT, criado por A. L em 27-05-2017.
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- A. L
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