Engineering Studies Comprehensive Course Flashcards

Vocabulary flashcards covering core concepts, material properties, manufacturing processes, fluid mechanics, and electronics from the Engineering Studies course notes.

Shear Stress

A measure of the internal reaction of a shearing force, calculated using the formula $f_s = \frac{P}{A}$.

Engineering Stress

Stress calculated by dividing the applied load by the original cross-sectional area of the material without accounting for area reduction.

Working Stress

The maximum stress a material is subjected to in service, which is kept below the yield stress and ultimate tensile stress ($\text{UTS}$).

Yield Stress

The stress level at which a marked increase in strain occurs without a corresponding increase in stress.

Proof Stress

The stress required to produce a specific amount of permanent strain in materials that do not exhibit a distinct yield point.

Toughness

The ability of a material to absorb energy prior to fracture, measured by the total area under its stress-strain curve.

Hooke's Law

A principle stating that stress is directly proportional to strain up to the elastic limit, expressed as $E = \frac{f}{e}$.

Factor of Safety

The ratio of safe working stress to either yield stress (for ductile materials) or ultimate tensile stress (for brittle materials).

Critical Crack Length

The threshold crack length in a brittle material beyond which failure is inevitable if stress levels are maintained.

Dye Penetrant Testing

A non-destructive test used to find small surface cracks by placing dye on the surface and examining it under UV light.

Ultrasonic Testing

A non-destructive test using high-frequency radio waves sent via a transmitter through a component to detect internal cavities via reflected signals.

Concrete Cancer

Structural degradation occurring when embedded steel reinforcement corrodes and expands, cracking the surrounding concrete.

Pre-tensioned Concrete

Concrete cast over a series of steel rods or cables that have been tensioned prior to pouring.

Post-tensioned Concrete

Concrete cast with internal tubes through which wires are pulled and tensioned after setting and curing, then grouted with cement slurry.

Galvanising

A corrosion protection method involving dipping steel in molten zinc to form a protective passive layer.

Dry Corrosion

Chemical reaction of metals or alloys with gases (such as oxygen in flue gases) at elevated temperatures in furnaces.

Galvanic Corrosion

Corrosion occurring when dissimilar metals are placed together in the presence of a corrosive environment.

Normalising

A heat treatment process involving heating steel up to the austenite region and cooling in still air to produce a fine grain structure.

Hot Rolling

A metal forming process where ingots are passed through rollers above the recrystallisation temperature to produce an unstressed product.

Cold Rolling

A metal process where rolling occurs below the recrystallisation temperature, producing dimensionally accurate products with elongated grains.

Investment Casting

A casting method using a wax pattern coated in refractory ceramic, which is melted out to leave a cavity for molten metal.

Impact Extrusion

A cold working process using hammer impact to force material inside a die around a punch.

Powder Forming

A manufacturing process involving compaction of blended metal powders in a mould, followed by sintering to diffuse atoms across grains.

Cartridge Brass

A ductile copper-zinc alloy containing $30\%$ zinc, commonly used for bullet cartridges.

Muntz Metal

A two-phase copper-zinc alloy containing $40\%$ zinc that is usually hot worked when shaped.

Admiralty Gunmetal

A bronze alloy containing $88\%$ copper, $10\%$ tin, $2\%$ zinc, and nickel, featuring excellent marine corrosion resistance.

Phosphor Bronze

A bronze containing phosphorus that offers high tensile strength, superior corrosion resistance, and a low coefficient of friction for bearings.

Precipitation Hardening

A two-step heat treatment process involving solution treatment at $530\,^\circ\text{C}$ followed by aging to restrict dislocations with precipitated phases.

Depletion Zone

An uncharged insulating region formed at a p-n semiconductor junction between fixed positive and negative charges.

Thermoplastics

Polymers that soften upon the application of heat and can be repeatedly remelted and reformed.

Thermosets

Polymers that undergo an irreversible chemical change when heated and cannot be remelted.

Blow Moulding

A polymer process where a molten tube inside a mould is expanded with air pressure against the cavity walls.

Rectification

The electrical process of converting alternating current ($\text{AC}$) into direct current ($\text{DC}$).

Archimedes' Principle

A principle stating that a body wholly or partially submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced.

Pascal's Principle

A fluid principle stating that pressure applied to an enclosed liquid is transmitted undiminished to every point in the fluid and container walls.

Hydrostatic Pressure

The static fluid pressure acting at right angles to every surface of an immersed object.

Brinell Hardness Test

A hardness test where a hardened steel ball is forced into a test piece under specified load conditions to calculate a hardness number.

Vickers Hardness Test

A hardness test using a small square pyramid indenter pressed into a test piece under specified load conditions.

Shore Scleroscope

A hardness test measuring the rebound height of a small striker dropped inside a vertical tube onto an item.

Bernoulli's Principle

A fluid dynamic principle stating that the pressure of a fluid decreases as the speed of the fluid increases.

Crevice Corrosion

Concentration cell corrosion occurring because of differing oxygen levels between the top and bottom of a crevice.

Modulation

The process of using a carrier sine wave to encode and transmit information signal variations.

Multiplexing

The process of placing multiple signals along a single communication channel to increase data capacity.