Sheet Metal Final Exam Questions and Answers Latest
2023 with complete solution
What is the major consideration of ALL sheet metal structures?
Strength VS Weight
What are the 2 major types of aircraft structures, concerning carrying stresses, or
loads?
Monocoque
Semi-monocoque
What is the difference between a monocoque and semi-monocoque structure?
A monocoque- when the stress of the structure is exerted on the skin and carries the
loads
Semi-monocoque- When a structure has internal structures that help carry the stress
and the loads.
What is the advantage and disadvantage of a monocoque structure?
ADV: lighter design bc of no internal structures
DISADV: the smallest dent or crack can destroy the structure
What is the advantage and disadvantage of a semi-monocoque?
ADV: Stronger
DISADV: Heavier
Give examples that can be used in a semi-monocoque structure.
Longerons
Stringers
formers
Bulkheads
Give the 6 types of loads (stresses) and define them.
Tension: stress that pulls apart a structure
compression: stress that pushes together a structure
Bending: a combo of tension and compression
Torsion: stress that tends to twist
Shear: two stress that acting against each other but not in line
Bearing: the stress a rivet or bolt puts on a hole
What is the 2 general structural considerations?
the rivet shear strength should be slightly less than the bearing strength of the material
Stresses need to flow evenly throughout the structure
What is the general idea that repairs should do?
, allow stresses to flow from the structure, to repair, over the damage, and back to the
structure
What is the advantages and disadvantage to aluminum alloy?
ADV: Good strength to weight ratio
DISAVD: aluminum in an alloy corrodes easily
What is the solution to prevent corrosion of an aluminium alloy?
Coat the alloy in pure aluminum, which is called "Alcad"
What does the first digit in the designation of an aluminum alloy mean?
it is the number of the major alloying elements
Give the 6 numbers and alloy for the first digit meanings
2-copper
3-manganese
4-silicon
5- magnesium
6- magnesium and silicon
7- zinc
What are the 3 methods of heat treating aluminum alloys? and define them.
Solution heat treating- heat to just below its melting point, soak in alloying element, then
quench
Precipitation heat treating- heat will below melting point and allow to precipitate and cool
slowly
Annealing- heat to well below melting pint and cool slowly
What does it mean when an alloy has a -F heat treatment?
-F: as fabricated
What does it mean when an alloy has a -O heat treatment?
-O, fully annealed
What does it mean when an alloy has a -T heat treatment?
-T, heat treated according to number
What does it mean when an alloy has a -H heat treatment?
-H, work hardened according to number
What are the 3 requirements for corrosion to occur?
A potential difference between two dissimilar metals
A path between metals
An electrolyte
What is the correct term for "Dissimilar metal corrosion?"
galvanic corrosion
What are the 3 ways to prevent corrosion?
Cladding
Artificial oxide
Organic Film (paint)
What is the advantage and disadvantage of aluminum alloy based composites?
2023 with complete solution
What is the major consideration of ALL sheet metal structures?
Strength VS Weight
What are the 2 major types of aircraft structures, concerning carrying stresses, or
loads?
Monocoque
Semi-monocoque
What is the difference between a monocoque and semi-monocoque structure?
A monocoque- when the stress of the structure is exerted on the skin and carries the
loads
Semi-monocoque- When a structure has internal structures that help carry the stress
and the loads.
What is the advantage and disadvantage of a monocoque structure?
ADV: lighter design bc of no internal structures
DISADV: the smallest dent or crack can destroy the structure
What is the advantage and disadvantage of a semi-monocoque?
ADV: Stronger
DISADV: Heavier
Give examples that can be used in a semi-monocoque structure.
Longerons
Stringers
formers
Bulkheads
Give the 6 types of loads (stresses) and define them.
Tension: stress that pulls apart a structure
compression: stress that pushes together a structure
Bending: a combo of tension and compression
Torsion: stress that tends to twist
Shear: two stress that acting against each other but not in line
Bearing: the stress a rivet or bolt puts on a hole
What is the 2 general structural considerations?
the rivet shear strength should be slightly less than the bearing strength of the material
Stresses need to flow evenly throughout the structure
What is the general idea that repairs should do?
, allow stresses to flow from the structure, to repair, over the damage, and back to the
structure
What is the advantages and disadvantage to aluminum alloy?
ADV: Good strength to weight ratio
DISAVD: aluminum in an alloy corrodes easily
What is the solution to prevent corrosion of an aluminium alloy?
Coat the alloy in pure aluminum, which is called "Alcad"
What does the first digit in the designation of an aluminum alloy mean?
it is the number of the major alloying elements
Give the 6 numbers and alloy for the first digit meanings
2-copper
3-manganese
4-silicon
5- magnesium
6- magnesium and silicon
7- zinc
What are the 3 methods of heat treating aluminum alloys? and define them.
Solution heat treating- heat to just below its melting point, soak in alloying element, then
quench
Precipitation heat treating- heat will below melting point and allow to precipitate and cool
slowly
Annealing- heat to well below melting pint and cool slowly
What does it mean when an alloy has a -F heat treatment?
-F: as fabricated
What does it mean when an alloy has a -O heat treatment?
-O, fully annealed
What does it mean when an alloy has a -T heat treatment?
-T, heat treated according to number
What does it mean when an alloy has a -H heat treatment?
-H, work hardened according to number
What are the 3 requirements for corrosion to occur?
A potential difference between two dissimilar metals
A path between metals
An electrolyte
What is the correct term for "Dissimilar metal corrosion?"
galvanic corrosion
What are the 3 ways to prevent corrosion?
Cladding
Artificial oxide
Organic Film (paint)
What is the advantage and disadvantage of aluminum alloy based composites?
