Structures

StructuresA structure is an arrangement of parts

joined strongly together.

Most objects are arrangements of parts, e.g.

atoms, crystals, cells

Crystals

Atoms / Cells

Structures

There are many different types of structures in existence

Can you name some structures?

Examples of structures include – Buildings, Bridges, Cranes, Chairs.

Eiffel Tower

Golden Gate

Structures

This picture shows Buildings, a tower crane and scaffolding

What do you think contributes to strength in structures?

Factors that contribute to strength in structures.• The strength of the material• The shape of the parts• The method used to join them together• The manner in which they are arranged

Tribal Home

StructuresThere are many very strong structures to be found in nature.

How many can you name?

Spiders Web Trees

StructuresNaturally strong features in useful designs

Bee honeycomb Honeycomb floor mat

Mount Everest Pyramid Egypt

Structures

Naturally occurring structures include:

• A grass leaf• A water lily• A palm tree leaf• Sea arch • Car shell

Grass

Palm tree

Water lily

Sea arch

Shell

Structures

Grass leaves have a honeycomb structure which, although very light, are also thick and strong.

Grass leaf under a microscope

Honeycomb used as a core in sandwiched structures, boards and flooring.

StructuresWater lilies have a web-like

structure,which grows from the centre to the outside of the Leaf giving it strength.

Above the view of the underside of a water lily

The Eiffel tower’s giant Lily Pad design of the future.

A structure made with parts that extend to meet each other

StructuresPalm tree leaves, though light, gain theirstrength from thin sheets folded into corrugations.

Palm tree leaf

Corrugated roofing

Corrugation used in packaging

StructuresSea Arch.Coastal features, formedby weathering

Sea arch

Steel arch used to support a roadway

Roman Arch

Structures

Shells provide shelter, and protect.

Thin-shell structures are light weight constructions

Structures

Beams come in various shapes and sizes

A beam is a strip or section of material used to span a distance

Beam

Structures

Frames are structures made from sections of materials.

The shape which is repeated in the images is the triangle.

StructuresA triangle is one of the strongest frame shapes known to man. The implementation of this concept in design is known as triangulation.

member

joint

Adding one more member makes the frame stable.

Structures

• A strut is the part, which has compressive forces acting upon it. • A tie is the part of a structure which has tensile forces acting upon it.

Wal

l

Tie

Strut

60Kg

StructuresCalculating Forces

The frame opposite supports a Mass of 60Kg.

Pin A in the sketch is in equilibrium.

Calculate the size of the forces acting on members B and C in the frame.

Triangle of Forces diagram.

The force at B is calculated as: 600 Cos 60° = (600)(0.5) = 300N

The force at C is calculated as: 600 Sin 60° = (600)(0.866) =519.6N

In order to calculate the force of the Mass in Newton’s, the Mass must be Multiplied by 9.81N, rounded to (10).Therefore force equals 600N.

300N

519.6N 60Kg

StructuresFactor of Safety is used to provide a margin of lee-way of flexibility over the theoretical capacityof the item in question.