What is a member in tension called?
Tie
What is a member in compression called?
Strut
What conditions allow beam to be in equilibrium?
ΣM Clockwise = ΣM anticlockwise
ΣF up = ΣF down
What loads do rollers take?
Only vertical
What loads do hinges take?
Vertical and horizontal
What is a UDL?
Uniformally Distributed Load
How to calculate point force of UDL?
w (total force) x d (UDL length) = F (point force)- which applies at 1/2d
What does nodal analysis do?
Analyses forces within a structure and whether they are in tension or compression.
What is strength?
Materials ability to resist a force.
Mild steel is strong only in tension.
Concrete is strong only in compression.
What is elasticity?
A materials ability to stretch and return to it’s original shape.
Rubber is very elastic
What is plasticity?
A materials ability to change shape under a load and remain that shape.
Clay is plastic.
What is ductility?
Materials ability to stretch without breaking
Copper
What is brittleness?
Easily cracked, snapped or broken with force.
Glass
What is malleability?
Can be shaped, worked or formed without breaking.
What is overloading?
Structure carries more load than designed for.
Causes bending, breaking or collapse.
What is joint failure?
Connections between parts fail.
E.g. bolts, welds, rivets etc.
Causes by poor workmanship, incorrect design, loosening over time
What is material failure?
The material is not strong enough.
Happens due to poor quality, wrong material or defects.
Corrosion, fracture, deformation
What is fatigue.
Failure after repeated loading and unloading, even if load is below maximum strength.
Cracks form and grow until sudden breakage occur.
What is strains formula?
Strain = Change in Length/ Original Length
Does strain have a unit?
No
What is the formula for stress?
Stress = Force/Area
What are the units for stress?
Nmm^-2
