Metallurgy Flashcards
Doesn’t have a bone type structure and relies on the strength of its skin to carry the stress
Monocoque
Has bone-type structure
primarily made of heat-treated aluminum, heavier internal parts and thicker skin to carry loads, it is the preferred method of constructing an all-aluminum fuselage, and has stringers
Semi-monocoque
Has vertical members
- Used in old aircrafts
- wood/metal structure
- Difficult to streamline
- Box with tubular longerons + vertical members
Pratt Truss
Doesn’t have vertical members
- Longerons + Diagonal members
- force transfers to other structures
- Capable to carry tension + compression
- Reduces amount of web works
- more space, strength and rigidity
- Better streamline
Warren Truss
This is very light and adequate for rubber tension and flight loads but unsupported lengths of longeron between nodes make it difficult to handle without breaking
Warren Truss Fuselage
This is heavier but the verticals and nodes make it easier to handle without breaking the unsupported lengths of longeron
Modified Pratt Truss fuselage
Ability of that material to resist stress without breaking
Strength
is that point at which a load would cause an initial indication of permanent distortion. It is measured in PSI
Yield Strength
is that point at which a material would fail under a shear force. Also measured in PSI
Shear strength
is the ability of a material to resist the forces that tend to damage it at the point of an applied load
Bearing Strength
The relationship between the strength of a material and its weight per cubic inch, expressed as a ration is known as
Strength - to weight ratio
Ability of a metal to resist abrasion, penetration, cutting action or permanent distortion
may also increase by cold-working the metal and in the case of steel and certain aluminum alloy, by heat treatment
Hardness
These two properties are closely associated properties of metal
Hardness and strength
Extent which it can be hammered, rolled or pressed into various shapes without cracking, breaking, or having detrimental effects.
- Necessary property in sheet metal that is working into curved shapes such as cowlings, fairings and wingtips
Mallebility
This specific material is a great example of malleable material
Copper
property of a metal which permits it to be permanently drawn, bent, or twisted into various shapes without breaking
Ductility
Similar to malleability
- Essential for metals used in making wires and tubing
- Ductile metals are greatly preferred for aircraft use because of their forming ease and resistance to failure under shock loads
- Aluminum alloys are used for cowl rings, fuselage, wing skin, formed or extruded parts such as ribs, spars or bulkheads
- chromium molybdenum steel is also easily formed into desired shapes
Ductility
property of a metal which allows little bending or deformation without shattering, - Brittle metals apt to break or crack without change of shape
- Because structural metals are often subjected to shock loads, brittleness is not a very desirable property
Brittleness
Cast iron, aluminum and very hard steel and are great example of…?
Brittleness
ability of a metal to transmit heat or electricity
Conductivity
ability of a metal to freely accept and release electrons where an electrical current is applied
Electrical conductivity
This helps eliminate radio interference in aircrafts and must be considered
Electrical conductivity
enables a metal to return to its original shape, when force which causes the change of shape is removed
Elasticity
each metal has a point known as elastic limit beyond which it cannot be loaded without causing permanent distortion
Elastic limit
Spring steel is a great example of this…?
Elastic Limit
withstand tearing or shearing and may be stretched or otherwise deformed without breaking
Toughness
This property is extremely desirable in aircraft metals
Toughness
ability of a metal to become liquid by the application of heat
Fusibility
Welding is an example of this term
Fusibility
Steel fuses around X Degrees Fahrenheit
2600
Aluminum alloys will fuse approximately around X degrees Farenheit
1250
mass of a unity volume of a material is called
Density
This is critical when choosing a material to be used in the design of a part, so that the proper weight and balance of the aircraft can be maintained
Density
Groups of metals having iron as their principle element is considered?
Ferrous metals
When combined with limestone and melted down, this can be converted into what is commonly known as
Pig Iron
Carbon added to pig iron up to approx. 1%, the product is vastly superior to iron alone and is classified as
Carbon steel
A base metal (such as steel) to which small quantities of other metals have been added is called an
Alloy
This steel element varies between 0.06% to 1.25% and is called what?
Carbon Steel
Steels of this grade are used for making items such as, safety wire, certain nuts, cable bushings or threaded rod ends
Low Carbon Steel
This is adaptable for machining or forging
Medium-Carbon Steel
In the fully heat-treated condition, it is very hard, will withstand high shear and wear, and will have minimal deformation and has limited use in aircrafts
High-Carbon steel
