STRUCTURES

DEFINITION OF STRUCTURE:

A structure is an object that has a definite shape and size and serves to a purpose or function.

CLASSIFYING STRUCTURES

Natural

- not made by people              

- occur naturally in the environment                                                     

E.g. Spider´s web, tree, beehive, cave.

Manufactured

- built by people
- many are modelled after natural structures
E.g.: car, building, bike, igloo

Structures can also be classified by their Design

Mass Structures: pyramid, church, roman bridges

Frame Structures: building, bike

Shell Structures: car, washing machine, computer, igloo

FUNCTION

What is the structure supposed to do? What was it designed for?
Most structures have several functions, which may include:

. supporting (its own weight)
· containing (substances)
· transporting

MAIN FORCES

Tension forces stretch a material by pulling its ends apart

Compression forces crush a material by squeezing it together.

Shear forces bend or tear a material by pressing different parts in opposite directions at the same time.

Torsion forces twist a material by turning the ends in opposite directions.

A bending force is a combination of tension and compression