Engineering Statics and Material Properties

Flashcards covering forces, equilibrium, material modification, alloys and recycling.

A __ is defined as the interaction between bodies or a 'push or pull' in a given direction.

force

According to Newton's Law, for every action (force) there is an and reaction (force).

equal, opposite

The basic formulae for determining values of force are or _.

F=ma, F=mg

Force is measured in __ (N).

Newton's

__ force - the attraction between the mass and the Earth (F= mg)

Weight

__ force - the force applied to an object from outside the object (F = ma)

Action

__ force - the force applied to a body to balance an action force or weight force

Reaction

__ force - the force set up between objects that tend to prevent or reduce motion. Friction is a special reaction force.

Friction

__ forces: These are forces that all pass through the same point.

Concurrent

__ forces: This is a system of forces that are not concurrent. They may intersect at various points or be parallel.

Non-concurrent

__ forces: This is a system of forces where the forces all act along the same line.

Co-linear

__ force: This force wants to make one material cut through another material.

Shear

__ forces are basically those which twist or tend to twist a component.

Torsional

Unlike scalar quantities, __ quantities must be added in a way that will take into account both their magnitude and direction.

vector

If the forces are not co-linear then their __ must be taken into consideration.

direction

An __ creates equilibrium and a 'resultant' is the total effect of the other forces.

equilibrant

The principle of __ of a force, relates to the fact that a force may be relocated at any position along its line of action, with the same magnitude and direction and sense and still have the same effect.

transmissibility

A three-force system may be in __ if the lines of action of the three forces pass through a common point, that is, they are concurrent, and the sum of the horizontal and vertical components are zero.

equilibrium

The term __ describes a turning effect (rotation) as a result of a force being applied to an object at a distance from a fixed point called the fulcrum or pivot.

moment

The turning effect is known as __ (a vector) and is the product of the force in Newtons and the distance in metres.

torque

When two equal and opposite forces act together they are known as __.

collinear

A __ may be defined as two parallel, co-planar forces of the same magnitude and direction but opposite sense, that produce or tend to produce rotation but not translation

couple

is the term used to describe a system where a body is at 'rest'.

Equilibrium

If a material is worked at a temperature below its __ temperature, the metal deforms by atoms slipping along shear planes.

recrystallisation

__ is the controlled heating and cooling of a material to purposely change its mechanical properties.

Heat treatment

__ removes stress, to soften the material. Heat the steel to about 900°C to austenitise.

Annealing

__ refines the grain structure, inducing toughness. The steel is heated to above 900°C to relieve stress then cooled in air.

Normalising

__ removes brittleness whilst retaining most of the hardness. The metal is heated to between 200°C and 600°C and then allowed to cool, the temperature being dependent on the required properties.

Tempering

__ only hardens the 'skin' of the material, leaving the core soft by comparison.

Case hardening

__ hardening also known as age hardening is a treatment that produces a uniformly dispersed fine, hard precipitate within a softer, more ductile matrix.

Precipitation

___, rolling, forging and other forming processes change the physical structure and mechanical properties of the metal.

Casting

__ alloys contain iron as their main constituent.

Ferrous

The __ System consists of ferrite (or alpha iron), austenite, cementite and pearlite.

Iron-Carbon

An __ is the combination of two or more metals, or metals and non-metals, which form a solid solution at room temperature.

alloy

___ solid solutions occur between materials with similar sized atoms.

Substitutional

__ solid solutions occur when the atoms are of differing sizes; (e.g. iron and carbon).

Interstitial

___ is very important to engineers. Many of the materials that the engineer uses are not renewable.

Recycling

The hierarchy of __ places waste reduction at the top, followed by reuse, then recycling and finally disposal as the most undesirable option.

waste management

__ reduction is any technique, process or activity which avoids, eliminates or reduces waste at its source (i.e. during production).

Waste

involves using a product or package more than once for its original purpose or re-using it for another application.

Reuse

__ is the collection, separation, clean-up and processing of waste material to produce a marketable material and/or product.

Recycling