Stress-Strain Curves in Detail - A Level Physics

This video explains stress-strain curves in more detail for A Level Physics.
In addition to the other video on this topic, this goes into a bit more detail and the four key points you would expect to see on a stress-strain graph for a typical ductile material.
Thanks for watching,
Lewis
This video is recommended for anyone studying A Level Physics in the following exam boards:
AQA
CIE
Edexcel
Edexcel IAL
Eduqas
IB
OCR A
OCR B
WJEC
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[@mhamzahrizwan]

Amazing explanation!
Thank you and keep up the good work!

[@jimmij9415]

Brilliant!

[@alevelsdemystified3410]

Can you please explain what fracture stress is as well?

[@lilgooseboi7354]

its the stress required for a material to fracture (break). lmao you might be in uni by now but ah well hope it helped

[@rishika_anand]

Thanks sir

[@nobleofftrack741]

Dam it my test was yesterday. But still a great video. 😀

[@mattwhitelock4725]

Love the videos, very clear explanations.
Not sure if you take requests, but would you be able to do some videos on the "looking inside materials" part of A level physics? I'm on OCR B, the 5th chapter, all about how materials look/behave on the microscopic scale, is extremely confusing - the textbook seems to go into unnecessary detail and makes it confusing by overcomplicating, and the CGP revision guide barely touches the subject.
The concepts I find confusing - Dislocations, alloying, crystalline/polycrystalline materials, stress concentration, crack propagation, toughness vs strength, directional vs non-directional bonds, necking, etc.
It's hard to find stuff on these topics on youtube, so perhaps something other people would like covering too - I know most of my class finds these topics very confusing. Thanks.

[@the_hasnat]

Is the area underneatht the whole graph energy per unit volume or is it only where they are proportional.

[@mattwhitelock4725]

Also, at 1:19 you mention how after the limit of proportionality we begin to see elastic behaviour. But doesn't the material also behave elastically in the region of proportionality? I thought it behaved elastically all the way up until the elastic limit, and then behaved plastically all after that.

[@PhysicsOnline]

Matt Whitelock You're right, I just said the wrong thing in the video. It behaves elastically up until the elastic limit.

[@sporech9374]

What is given by the area underneath the stress/strain graph?

[@CHEESYhairyGASH]

toughness, a measure of energy per unit volume - effectively the amount of energy the material absorbs before breaking. To be tough a material must be strong and ductile - so as to have a large area beneath its stress-strain curve.

[@kanavkapoor3055]

Are UTS and "Breaking Stress" the same thing?

[@TaMeApollo]

Kanav Kapoor no they aren't, UTS is ultimate tensile stress which is the maximum stress a material can withstand where as breaking stress is the stress required to break the material

[@mattwhitelock4725]

Surely the maximum stress a material can withstand is the maximum stress before it breaks? So therefore wouldn't that be the stress required to break the material?

[@sambowater3972]

Why is there a little flick up at the end just before UTS?

[@BliiiiBlaaaaBluuuub]

do we need to know graphs for different materials?

[@mattwhitelock4725]

It depends on what exam board you are doing - check your specification - it lists all the content you need to know for the exam.
Ask your teachers if you don't know which specification you're doing, or it will say on the front of your textbook - it is likely either OCR A, OCR B, AQA, or Edexcel.

[@BliiiiBlaaaaBluuuub]

Matt Whitelock aqa

[@mattwhitelock4725]

Okay, then google "AQA A level physics specification" and you should find it. Go down to the topic on materials, and look to see if it says there are any graphs you need to know.

[@BliiiiBlaaaaBluuuub]

Matt Whitelock it's not very specific. so I'm kinda confused

[@mattwhitelock4725]

Does it say you need to know any specific graphs? If not, then you don't need to know them.

[@ibadalvi32]

why are your year 13 material all requiring for pay?

[@joshplayz474]

This is not quite right, the Yield point and Elastic limit are actually the same point on a stress strain graph.

[@mohammedzohair4035]

Yeah bruhh true

[@lexoticstudios5669]

No they're not joke man... yield stress and elastic limit are completely different you absolute joke man trying to correct my dad

[@ellielovehavingmuscle]

@@lexoticstudios5669your dad?

[@Super-Duper_Space_Goat]

The really aren't.