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
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Compression forces crush a material by squeezing it together.
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Shear forces bend or tear a material by pressing different parts
in opposite directions at the same time.
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Torsion forces twist a material by turning the ends in opposite
directions.
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A bending force is a combination of tension and
compression
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