Reaching Breaking Point: Materials, Stresses, & Toughness: Crash Course Engineering #18
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Date: 2022-04-04
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• TED-Ed
Comments and reviews: 10
Gilder
Wow. What a needlessly convoluted and complicated way to explain this.
Too Technical with too little Explanation.
I actually learned such stuff and yet aside from terminology I hardly was able to comprehend any of what you said and basicly had to remember things from what I learned myself to realize what your Talking about.
In Essence your Explaining what the Words mean but give it absolutely Zero Practical Knowledge to go with.
For an Actual Engineer this might be understandable.
But for those of us which are not Educated in Engineering especially even if we do have education in this field due to other Areas of Expertise this is really really hard to grasp.
One example.
Your actually using a Steel Beam as your first Example and then actually Show a Bridge.
And you Explain that Materials will Bend and Break if a certain amount of Force is applied.
Yet one of the most Importand Examples on Materials Qualities and one of the Reasons why Steel is such a Widely used Material for Bridges remains entirely unmentioned.
One of the First things we Learned was about Permanent Deformation and Reversive Deformation (sorry if its not the correct Terminology in English I didnt learn it in English )
You are actually later on mentioning the effect of continues Stress and that smaller amounts of stress might reduce the breaking Point of the Material over time.
Yet again in your explanation it basicly sounds like Material once it starts deforming is automaticly permanently damaged and will reduce its breaking point.
Leaving out the Property of Materials being able to withstand certain repeated stress levels by deforming and then returning to Original form after the stress lets off.
Or maybe you actually mentioned it but I didnt understand it: P
Anyways.
I think you should Redo this Video or maybe do a Second Video on it.
I somehow dont think that many people without extensive prior knowledge in this field will actually be able to make sense of this right now
reply
Wow. What a needlessly convoluted and complicated way to explain this.
Too Technical with too little Explanation.
I actually learned such stuff and yet aside from terminology I hardly was able to comprehend any of what you said and basicly had to remember things from what I learned myself to realize what your Talking about.
In Essence your Explaining what the Words mean but give it absolutely Zero Practical Knowledge to go with.
For an Actual Engineer this might be understandable.
But for those of us which are not Educated in Engineering especially even if we do have education in this field due to other Areas of Expertise this is really really hard to grasp.
One example.
Your actually using a Steel Beam as your first Example and then actually Show a Bridge.
And you Explain that Materials will Bend and Break if a certain amount of Force is applied.
Yet one of the most Importand Examples on Materials Qualities and one of the Reasons why Steel is such a Widely used Material for Bridges remains entirely unmentioned.
One of the First things we Learned was about Permanent Deformation and Reversive Deformation (sorry if its not the correct Terminology in English I didnt learn it in English )
You are actually later on mentioning the effect of continues Stress and that smaller amounts of stress might reduce the breaking Point of the Material over time.
Yet again in your explanation it basicly sounds like Material once it starts deforming is automaticly permanently damaged and will reduce its breaking point.
Leaving out the Property of Materials being able to withstand certain repeated stress levels by deforming and then returning to Original form after the stress lets off.
Or maybe you actually mentioned it but I didnt understand it: P
Anyways.
I think you should Redo this Video or maybe do a Second Video on it.
I somehow dont think that many people without extensive prior knowledge in this field will actually be able to make sense of this right now
reply
Daniel
There's an old poem that comes to mind here. It was authored by Rudyard Kipling in 1935.
THE careful text-books measure
(Let all who build beware)
The load, the shock, the pressure
Material can bear.
So, when the buckled girder
Lets down the grinding span,
'The blame of loss, or murder,
Is laid upon the man.
Not on the Stuff-the Man!
But in our daily dealing
With stone and steel, we find
The Gods have no such feeling
Of justice toward mankind.
To no set gauge they make us-
For no laid course prepare-
And presently o'ertake us
With loads we cannot bear:
Too merciless to bear.
The prudent text-books give it
In tables at the end
'The stress that shears a rivet
Or makes a tie-bar bend-
'What traffic wrecks macadam-
What concrete should endure-
but we, poor Sons of Adam
Have no such literature,
To warn us or make sure!
We hold all Earth to plunder-
All Time and Space as well-
Too wonder-stale to wonder
At each new miracle;
Till, in the mid-illusion
Of Godhead 'neath our hand,
Falls multiple confusion
On all we did or planned-
The mighty works we planned.
We only of Creation
(0h, luckier bridge and rail)
Abide the twin damnation-
To fail and know we fail.
Yet we - by which sole token
We know we once were Gods-
Take shame in being broken
However great the odds-
The burden of the Odds.
Oh, veiled and secret Power
Whose paths we seek in vain,
Be with us in our hour
Of overthrow and pain;
That we - by which sure token
We know Thy ways are true-
In spite of being broken,
Because of being broken
May rise and build anew
Stand up and build anew.
reply
There's an old poem that comes to mind here. It was authored by Rudyard Kipling in 1935.
THE careful text-books measure
(Let all who build beware)
The load, the shock, the pressure
Material can bear.
So, when the buckled girder
Lets down the grinding span,
'The blame of loss, or murder,
Is laid upon the man.
Not on the Stuff-the Man!
But in our daily dealing
With stone and steel, we find
The Gods have no such feeling
Of justice toward mankind.
To no set gauge they make us-
For no laid course prepare-
And presently o'ertake us
With loads we cannot bear:
Too merciless to bear.
The prudent text-books give it
In tables at the end
'The stress that shears a rivet
Or makes a tie-bar bend-
'What traffic wrecks macadam-
What concrete should endure-
but we, poor Sons of Adam
Have no such literature,
To warn us or make sure!
We hold all Earth to plunder-
All Time and Space as well-
Too wonder-stale to wonder
At each new miracle;
Till, in the mid-illusion
Of Godhead 'neath our hand,
Falls multiple confusion
On all we did or planned-
The mighty works we planned.
We only of Creation
(0h, luckier bridge and rail)
Abide the twin damnation-
To fail and know we fail.
Yet we - by which sole token
We know we once were Gods-
Take shame in being broken
However great the odds-
The burden of the Odds.
Oh, veiled and secret Power
Whose paths we seek in vain,
Be with us in our hour
Of overthrow and pain;
That we - by which sure token
We know Thy ways are true-
In spite of being broken,
Because of being broken
May rise and build anew
Stand up and build anew.
reply
Chin
5: 58-6: 06
-But as you apply even more stress. the material will begin to deform and stretch along its cross-section as well as its length-
Just want to suggest adding in some detail here as the above sentence seems a bit ambiguous. Even in the elastic region of the stress-strain graph, all (normal) materials do experience deformation span/transverse-wise, and not just lengthwise before the yield point (see Poisson effect and/or Poisson-s ratio.
In the elastic region, this effect is uniform across the material, as the cross-section area deforms uniformly across the entire length. At the yield point and beyond, this deformation begins to be non-uniform and is localized instead - hence the specimen necking/getting thinner in the middle before failure occurs there. (Also, I feel that defining the yield point as being the point beyond which the material can no longer return to its original shape to be a clearer explanation than the above.
To summarize then, perhaps it would be better to phrase the above as -the material will begin to deform and stretch -non-uniformly- along its cross-section as well as its length- - or something along this tune?
Still, thanks for summarizing a semester-s worth of introductory materials engineering so well! Wanted to add this to prevent any misconceptions of when transverse deformation occurs.
reply
5: 58-6: 06
-But as you apply even more stress. the material will begin to deform and stretch along its cross-section as well as its length-
Just want to suggest adding in some detail here as the above sentence seems a bit ambiguous. Even in the elastic region of the stress-strain graph, all (normal) materials do experience deformation span/transverse-wise, and not just lengthwise before the yield point (see Poisson effect and/or Poisson-s ratio.
In the elastic region, this effect is uniform across the material, as the cross-section area deforms uniformly across the entire length. At the yield point and beyond, this deformation begins to be non-uniform and is localized instead - hence the specimen necking/getting thinner in the middle before failure occurs there. (Also, I feel that defining the yield point as being the point beyond which the material can no longer return to its original shape to be a clearer explanation than the above.
To summarize then, perhaps it would be better to phrase the above as -the material will begin to deform and stretch -non-uniformly- along its cross-section as well as its length- - or something along this tune?
Still, thanks for summarizing a semester-s worth of introductory materials engineering so well! Wanted to add this to prevent any misconceptions of when transverse deformation occurs.
reply
nacoran
In the harmonica world there are metal reeds. Historically they used bell brass. Today there are two main materials. bronze-phosphor and stainless steel (not sure what grade but it's magnetic but still good with moisture. There is a debate over which last longer. People fall into both camps, but I've noticed that the people who say steel lasts long self-describe themselves as hard players. My guess is that the stainless is staying under the fatigue stress levels with gentle players but more vulnerable at higher levels. I've read that under certain levels steel (and titanium) can undergo nearly infinite cycles without breaking. I also know when they are retuning reeds a lot of customizers prefer to polish to remove metal rather than just scratch the reeds because they are worried that scratches will create weak points that could lead to reed failure. (At $40 a pop for a harmonica, with 20 reeds per harp, with 12 harps in your set people worry about details like this)
reply
In the harmonica world there are metal reeds. Historically they used bell brass. Today there are two main materials. bronze-phosphor and stainless steel (not sure what grade but it's magnetic but still good with moisture. There is a debate over which last longer. People fall into both camps, but I've noticed that the people who say steel lasts long self-describe themselves as hard players. My guess is that the stainless is staying under the fatigue stress levels with gentle players but more vulnerable at higher levels. I've read that under certain levels steel (and titanium) can undergo nearly infinite cycles without breaking. I also know when they are retuning reeds a lot of customizers prefer to polish to remove metal rather than just scratch the reeds because they are worried that scratches will create weak points that could lead to reed failure. (At $40 a pop for a harmonica, with 20 reeds per harp, with 12 harps in your set people worry about details like this)
reply
verdatum
I can't put into words how much I love this. I'm a hobbyist blacksmith, and far too often in this realm we see these termed used far too loosely. This is because most blacksmiths haven't had the material engineering that evolved out of what the historical blacksmiths came to learn. Giving these words like strength, toughness, and hardness formal definitions makes them all so much more useful, but only to those who have taken the time to learn their proper formalized meanings. Videos like this, make that understanding so very much easier. As a teen, I tried to learn this from things like Modern Marvels on cable TV, and they would almost always get at least one critical aspect almost completely wrong.
reply
I can't put into words how much I love this. I'm a hobbyist blacksmith, and far too often in this realm we see these termed used far too loosely. This is because most blacksmiths haven't had the material engineering that evolved out of what the historical blacksmiths came to learn. Giving these words like strength, toughness, and hardness formal definitions makes them all so much more useful, but only to those who have taken the time to learn their proper formalized meanings. Videos like this, make that understanding so very much easier. As a teen, I tried to learn this from things like Modern Marvels on cable TV, and they would almost always get at least one critical aspect almost completely wrong.
reply
Tom
The revitalization of the Old Town Drawbridge experienced another setback this week, as engineers determined that the furniture upholstery used to construct the bridge towers soaks up water and creates an unstable foundation. This week-s collapse was the third in as many months.
Construction crews have tried building the bridge tower base supports from corrugated cardboard, non-dairy creamer, and ceramic bowls. Nothing has worked.
Engineers are asking for help in determining how proper bridge towers are made. If you have any tips, please write them on notebook paper and mail them to
Bridge Magic, LLC
PO Box 616
Do not use cursive or long words. Clearly labeled drawings are preferred.
reply
The revitalization of the Old Town Drawbridge experienced another setback this week, as engineers determined that the furniture upholstery used to construct the bridge towers soaks up water and creates an unstable foundation. This week-s collapse was the third in as many months.
Construction crews have tried building the bridge tower base supports from corrugated cardboard, non-dairy creamer, and ceramic bowls. Nothing has worked.
Engineers are asking for help in determining how proper bridge towers are made. If you have any tips, please write them on notebook paper and mail them to
Bridge Magic, LLC
PO Box 616
Do not use cursive or long words. Clearly labeled drawings are preferred.
reply
Arun
Of coure, I am a good student too who is greatly interested in the subject, that makes the test a bit biased, nonetheless, my absorption rate is a a good indicator of the the communication strength of the video.
reply
Of coure, I am a good student too who is greatly interested in the subject, that makes the test a bit biased, nonetheless, my absorption rate is a a good indicator of the the communication strength of the video.
reply
Zhu
I had hoped you'd would have mentioned transition temperatures for them resulting in such things in the Space Shuttle Challenger failure and possibly an important variable in the Titanic sinking.
reply
I had hoped you'd would have mentioned transition temperatures for them resulting in such things in the Space Shuttle Challenger failure and possibly an important variable in the Titanic sinking.
reply
Shemsy
The entirety of this engineering crash course(minus fluids) is taught in my a level classes like from 1-14 and from here to the semiconductor video is a level physics engineering or sumn lol
reply
The entirety of this engineering crash course(minus fluids) is taught in my a level classes like from 1-14 and from here to the semiconductor video is a level physics engineering or sumn lol
reply
JV
Minor pedantry here, but.
-Ep-SI-lon-? I am pretty sure it is supposed to be -EP-si-lon-. Second syllable is said like -see-, not -sigh-.
Minor linguist complain over. I do apologize.
reply
Minor pedantry here, but.
-Ep-SI-lon-? I am pretty sure it is supposed to be -EP-si-lon-. Second syllable is said like -see-, not -sigh-.
Minor linguist complain over. I do apologize.
reply
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