Science Unit 3 Quiz #2

4 ways structures can fail

Shear, Bend/Buckle, Torsion, Metal Fatigue

Shear Failing

When one section of a structure slides over another along its weakness

Bend/buckle

When compressive forces are exerted on a structure and causes the material to bend on the inside of the curve and pull/snap on the outside of the curve until it gives way

Torsion

Application of twisting forces to a structure

Metal fatigue

Metal weakening after experiencing bending or twisting forces over a period of time

Shearing

What does torsion cause?

3 things to think about when designing with forces

Distribute the load, direct forces using angles, shape the materials

Distributing load

Ensuring no part of the structure carries most of the load

Directing forces using angles

Direct forces along angled components so forces hold pieces together instead of pulling them apart

Shaping materials

Shape the materials to withstand a specific type of force

Examples of distributing the load

triangles

Examples of directing forces using angles

arches, keystones

Examples of shaping materials

“I-beam”, “T-beam”, corrugated cardboard

Cantilever

Horizontal board/span supported by a very strong column at one end

Braces

Used to direct the forces through the solid part of the structure to the ground

Buttress

Architectural structure built against a wall or arch to support it

Flying Buttress

Columns on the outside of a structure that connects to the building near the top to support outer walls

Eg. Notre Dame Cathedral, Westminster Abbey…

What are some famous examples of flying buttresses

Notre Dame Cathedral, Westminster Abbey

What are some examples of bend and buckle?

Blades of grass, car bumpers, accordions

What is an example of a structure that needs distributive load?

Frame structures that can get pushed and pulled out of shape.

What are 3 things designers need to keep in mind when building a stable structure?

Friction, low centre of gravity, large base

What does friction do?

Friction holds a structure in place because it resists motion.

How does friction occur?

By contact between two surfaces.

What is a problem with friction?

Too little or too much friction can cause problems.

What are some examples of friction?

Fasteners (nails/screws) and brick layers.

What is the low centre of gravity?

The specific point where all mass is evenly distributed around.

How would you find the centre of gravity in an irregular shape?

Based on the way the object balances and falls.

What does a large base do?

It increases stability.