QCAA Engineering EA key terms

An organised sequence of stages used to turn a need into a workable solution, typically including problem definition, research, concept generation, evaluation, prototyping, testing and refinement.

A short written statement that sets out the client's need, the intended user, the required outcomes and the boundaries within which a solution must be developed.

A limit that a solution must satisfy, such as available budget, permitted materials, deadline, safety regulation or physical space, and which cannot be traded away.

The measurable qualities a successful solution should display, used to compare competing concepts objectively and to judge whether the finished product meets its purpose.

A table that scores competing design options against weighted criteria, producing a total for each option so that the choice between concepts is transparent and defensible.

An accepted compromise in which improving one property or performance measure causes another to become worse, such as reducing mass at the cost of stiffness.

The internal force carried per unit area of a material's cross-section, usually expressed in megapascals, and calculated by dividing the applied load by the resisting area.

The change in length of a member divided by its original length, a dimensionless ratio that describes how much a material deforms under load.

The ratio of stress to strain while a material behaves elastically, representing its stiffness; a steep slope on a stress-strain graph indicates a stiff material.

The greatest stress a material can carry and still return to its original shape when the load is removed; loading beyond it leaves permanent deformation.

The stress at which a material begins to deform permanently, marking the transition from elastic to plastic behaviour and often used as the basis for allowable design stress.

The maximum stress a material can withstand while being pulled apart before necking and fracture, reported as the peak of a tensile stress-strain curve.

The ability of a material to stretch plastically before breaking, allowing it to be drawn into wire or to deform visibly and warn of impending failure.

The tendency of a material to fracture with little plastic deformation, so that it gives almost no warning before breaking when overloaded or struck.

The amount of energy a material absorbs before fracture, found from the area under a stress-strain curve and important where impact or shock loading is expected.

Progressive cracking and weakening of a component caused by repeated or fluctuating loads, which can cause failure at stresses well below the material's single-load strength.

The ratio of a material's or structure's failure strength to the maximum stress it is expected to experience, providing a margin for uncertainty, overload and material variation.

A sketch of an isolated body showing every external force and moment acting on it, with magnitudes, directions and locations, used as the basis for equilibrium equations.

The condition in which the net force and net moment on a body are both zero, so that a stationary structure remains at rest and does not translate or rotate.

The single force that has the same effect as two or more forces acting together, found by vector addition of their magnitudes and directions.

The turning effect of a force about a point, calculated as force multiplied by the perpendicular distance from the point to the line of action of the force.

A force exerted by a support, such as a pin, roller or fixed base, onto a structure in response to the applied loads, keeping the structure in equilibrium.

A lightweight framework of straight members joined at their ends into triangles, so that loads are carried mainly as tension or compression along the members rather than as bending.

Sudden sideways collapse of a slender member carrying compression, occurring when the compressive load exceeds a critical value that depends on length, stiffness and end conditions.

A quantity that has both magnitude and direction, such as force, velocity or acceleration, and which must be combined by geometric or trigonometric addition rather than simple arithmetic.

A quantity described fully by magnitude alone, with no direction, such as mass, time, energy, temperature or speed.

The rotational effect produced by a force applied at a distance from an axis, equal to force times perpendicular radius, and central to the design of shafts, gears and levers.

The ratio of the output force produced by a machine to the input force applied to it, indicating how much a lever, gear set or pulley system multiplies effort.

The ratio of useful energy or power output to total energy or power input, usually expressed as a percentage, with the shortfall lost mainly as heat and sound.

The change of energy from one form to another, such as chemical to electrical or kinetic to potential, in which total energy is conserved but some becomes less useful.

The principle that energy cannot be created or destroyed, only transferred or transformed, so the total energy in a closed system stays constant.

A drawing method that shows a three-dimensional object as separate front, top and side views arranged in a standard layout, with all views projected at right angles to each other.

A pictorial drawing in which the three principal axes are set 120 degrees apart, giving a three-dimensional impression while keeping lengths along the axes to a consistent scale.

A drawing convention in which each view is placed on the side of the object from which it is seen, so the top view sits above the front view; the standard used in Australia.

The practice of adding sizes, radii, angles and tolerances to a technical drawing in a standardised way so the part can be made without further measurement or guesswork.

The permitted variation in a dimension, given as an upper and lower limit, which balances the need for interchangeable parts against the cost of precise manufacture.

A drawing in which part of an object is imagined cut away and the exposed material is hatched, revealing internal features such as holes and cavities that hidden lines would obscure.

A digital three-dimensional representation of a part or assembly created in computer-aided design software, used for visualisation, simulation, drawing generation and manufacturing data.

A group of manufacturing methods, including additive printing, that build a physical model directly from digital data quickly so that form, fit and function can be checked early.

An early physical or virtual version of a product built to test concepts, confirm performance and uncover problems before committing to full-scale production.

The planned inspection and testing activities used to confirm that manufactured items meet specified requirements, keeping variation within the limits set by tolerances.

The longest sequence of dependent tasks in a project schedule, which fixes the shortest possible completion time and shows where delay directly postpones the deadline.

A horizontal bar chart that plots tasks against a calendar, showing each activity's start, duration and overlap so that scheduling and progress can be monitored visually.

A significant, clearly defined point in a project, such as completion of a design review or delivery of a prototype, used to track progress against the plan.

A published, agreed specification or code of practice that sets out requirements for safety, dimensions, testing or terminology, allowing consistent and interoperable engineering work.

A structured process of identifying hazards, judging how likely and how severe harm could be, and deciding on controls to reduce risk to an acceptable level.

A ranked order of safety measures that prefers eliminating a hazard, then substituting or engineering it out, before relying on administrative procedures and personal protective equipment.

The legal and ethical obligation of engineers and organisations to take reasonable steps to avoid foreseeable harm to users, workers, the public and the environment.

A set of professional principles, such as competence, honesty, public safety primacy and sustainability, that guides engineers' conduct and underpins public trust in the profession.

A situation in which an engineer's personal, financial or other interest could improperly influence professional judgement, requiring disclosure and management to protect integrity.

A technique that estimates environmental impacts across a product's whole life, from raw material extraction through manufacture, use and disposal or recycling.

Design that meets present needs while limiting resource use, emissions and waste, often by extending product life, using renewable or recycled materials and designing for disassembly.

A design philosophy in which materials circulate endlessly in technical or biological cycles, so that products at end of life become nutrients or feedstock rather than landfill.

Designing products so they can be produced economically and reliably, for example by reducing part count, simplifying shapes and choosing processes suited to the required quantity.