Can you think of some structures that are natural? Man-made?
Natural Structures: Structures not made or manufactured by people. Naturally occurring in nature.
Examples: feathers, sand dunes
Manufactured Structures: Structures that have been built by people. Would not naturally occur.
Examples: buildings, umbrellas, a jigsaw puzzle
Structure Designs: Mass, Frame and Shell
Mass
Formed from a solid piece of strong material
Has little or no space between inside, relying solely on its own mass to resist any force that may be acted on it
Usually the strongest of the three types of structures
Frame
Formed from a rigid arrangement of parts, or structural components, fastened together
The strength of the frame comes from how these parts are placed together
Lighter than solid structures because they use less material
Example: Skeleton
Shell
Has a solid outer surface, may be rounded or flat with a hollow inner area
Rounded outer area are stronger due to the curved area distributing the load around the whole surface
Hollow interior allows it to be lighter than solid structures
Function
A structure's use or purpose
Example: The function of an airplane or car is transportation
When a structure is built knowing the main function (i.e. comfort, transportation or shelter) of the structure will allow the designers to build it accordingly
Common Function but Different Design (Variation in Design)
Each structure performs a specific function and can vary in design
Common Function: provide covering for a building and protect what is inside Different Design: because they are all effective but are suited for different environments (climate), cultures, resources.
Describing Structures Things to Consider when Building a Structure:
1) Function: this is the job that the structure is designed to do e.g. a train bridge is designed to support the weight of the train. 2) Aesthetics: The pleasing appearance/ effect that an object has due to its design 3) Safety: Almost all structures are built with a large “margin of safety”. This means that structures are designed to withstand much more pressure than they would normally need to deal with e.g. a bridge can hold much more weight than it ever would have to. 4) Balancing Cost with Safety: It is difficult to design safe, well built projects that are not too expensive. 5) Materials: The properties of the material must match the purpose of the structure e.g. you would not build a bridge for cars out of rubber.
Aesthetics
The pleasing appearance /effect that an object has due to its design
Types of Materials
Composite Materials: are made from more than one materiale.g. concrete can be reinforced using steel rods.
Layered materials: layers of different materials pressed or glued together often produce useful products.These layers are called “laminations”e.g. layers of a juice box container involve paper, plastic and aluminum foil, making it lightweight, waterproof, and airtight.
Woven and Knit materials: weaving and knitting are effective ways to make flexible materials. E.g. yarn in dishcloths is woven together to be flexible & strong
When engineers choose what materials to use when building structures they must consider:
1) Cost of the material 2) Environmental Impact 3) Appearance 4) Energy Efficiency
Performance Requirements of a Structure
Performance Requirements of a Structure:
How well will a structure hold up under the load it was designed to carry out.
Important for safety, cost and efficiency
Performance Requirements should always be expressed in Maximum Weight
Example: Engineers need two conditions to decide what type of bridge is suitable: 1.What the bridge is crossing (water/land) 2.What kinds of loads the bridge will be supporting
Structural Strength: The ability of the structure to hold itself up
Structural Stability: The ability to maintain its position even if a force is acting on it.
Bill Nye: Architecture
NEWSPAPER CHALLENGE! Try this at home!
Using a maximum of 10 sheets of newspaper – attempt to build a structure that can hold at minimum a textbook (or something of a similar weight!) Using only 1 m or about 100 cm of masking tape.
You CANNOT attach your structure to a table of surface – it must be freestanding. And your structure must hold the weight off of the table.
Newspaper Challenge Review:
How did your structure hold the weight (textbooks) applied?
Was your structure successful?
What would you and your group change about your structure next time?