6. Materials & hardware - Q&A
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The Fatigue limit for steel is generally in the region of, compared to the static U.T.S
- 40%-60%.
- 60%-80%.
- 20%-40%.
the correct answer is 40%-60%.
This limiting stress is called the ‘Fatigue Limit’ and for steels, the fatigue limit is generally in the region of 40% to 60% of the value of the static ultimate tensile strength (UTS).
Extracted from KLM UK Engineering Notes for Module 6.
Which of the following are generally characteristic of aramid fibre (Kevlar) composites?
- High tensile strength and flexibility.
- Flexibility, stiffness and corrosive effect in contact with aluminium.
- High tensile strength, stiffness and ability to insulate electricity.
are u sure it is stiff and conducts electricity also.plz help.
On a pre-preg composite
- life can be extended by 12 months if stored above 40 degreesC
- life can be extended by 12 months if stored below 10 degreesC
- no life extension is allowed, it must be used immediately.
Any body out there??
Answer regarding storage above 40 degree Celsius seems absurd, i don't have in depth knowledge about the subject but i searched on the web concerning this question. Below are two web links which helped me get convinced that to extend the life of pre preg composite it needs to be stored in low temperature.
http://composite.about.com/od/eqptprepreggers/a/What-Are-Prepregs.htm
http://www.rfidjournal.com/articles/view?8704
Galvanic corrosion is most likely to be most rapid and severe when
- the surface area of the anodic metal is smaller than the surface area of the cathodic material.
- the surface area of the cathodic metal and the anodic material are approximately the same.
- the surface area of the cathodic metal is smaller than the surface area of the anodic material.
isn't the corrosion more rapid when the anodic metal is smaller in compare to cathdic metal
In the anodic film inspection and sealing test, if a good seal has been accomplished
- the dye mark will not rub off.
- the dye mark has no importance.
- the dye mark will rub off.
help please. i'm confused.
The colour code on sheet metal indicates
- only the specification of the material.
- the spec and gauge of the material.
- that the material is from an approved source.
any link plz
When examining a piece of metal through a magnifying glass, hair line cracks would indicate
- crevice corrosion.
- intergrannular corrosion.
- surface corrosion.
r u sure about the answer or could it be :surface corrosion'
Kevlar and Nomex are types of
- glass fibre composite.
- advanced composite.
- aluminium alloy.
Please explain to me the difference between. Glass fibre opposite and a advanced composite ?
Co-axial cables are used
- as they are able to handle high current.
- as the fields due to current flow in the inner and outer cancel each other out.
- as they are protected from electromagnetic interference.
Co-axial cables are used to prevent EM interference and o not cancel each other out. Incorrect answer I believe
A worm drive creates
- a drive in 2 planes and transmits both directions.
- a drive in 1 plane but transmits both directions.
- a drive in 2 planes but transmits 1 direction only.
Can somebody explain to me how a worm drive dives in 2 planes and a single direction? I believe it is 1 plane with 2 directions I.e. forwards nd reverse in the same plane
Galvanic action caused by dissimilar metal contact may best be prevented by
- applying a non-porous dielectric material between the surfaces.
- special precautions are not required if they are properly bonded.
- priming both the surfaces with a light coat of zinc chromate primer.
I agree with this answer but would a jointing compound not be the best method?
What would be the diameter and length of a solid rivet if the following markings are given, AS 162-408?
- 1/4 inch dia, 1/2 inch length.
- 1/2 inch dia, 1 inch length.
- 1/8 inch dia, 1/2 inch length.
What would be the diameter and length of a solid rivet if the following markings are given, AS 162-408?
• ¼ inch dia, ½ inch length.
• ½ inch dia, 1 inch length.
• 1/8 inch dia, ½ inch length.