Solids under Stress Flashcards
(25 cards)
Define Hookes Law
When the spring constant is directly
proportional to the extension
What is the equation for Hookes Law
f=kx
Force = Spring constant x extension
What is an elastic limit
When a material has been stretched too far and will not return to its original position
When you unload and load a spring, what does the graph look like
After the elastic limit it goes down and is parallel to the line going up, separated by the distance of the elastic limit
What is the young’s modulus equation
stress/strain
What is the equation for stress
Force/Area
What is the equation for strain
Change of Length / Length
What is a crystalline material
Contain crystals and are a regular array of particles
What is a Polycrystalline material
Contain a large amount of interlocking crystals
What are amorphous materials
No set order, in a random array like glass
What are polymers
Materials that are long repeats
of the same monomers
such as polyethylene
What is a ductile material
A material that can be drawn out into a string
What is elastic limit
The exact point where a material starts to plastically deform
What is edge dislocation
an additional plane of ions to a material which makes it lose its durability, leading into more deformations
How do you strengthen a metal
Alloying
More edge dislocations
increase grain size by reducing size by quenching
What is a brittle material
A material that breaks under pressure and doesn’t deform
Explain how to make tempered glass
Put glass under a lot of pressure
How to make steel concrete beams
There is a rod in the mould, the concrete is poured into it and the metal beam get stuck. It gets expanded outwards but doesn’t allow the concrete to break
What is it called when a material stretches and the state it is in before breaking
Necking
In which cases does unloading ≠ loading
If the material is Rubber or there has been deformation
What is the extension in springs if they are parallel
K1+k2
What is the extension of springs in series
1/k + 1/k2
What is Hookes Law
Extension of a spring is directly proportional to its tension
