Questions tagged [stress-strain]
811 questions
203
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Why do we bend a book to keep it straight?
I noticed that I have been bending my book all along, when I was reading it with one hand.
This also works for plane flexible sheets of any material.
Illustration using an A4 sheet
Without bending the sheet:
With a bend along perpendicular…
AlphaLife
- 13,439
100
votes
11 answers
If I pull a metal bar for long enough with a constant small force, will it eventually break?
Let's say I have a strong metal bar. I pull it apart with a very small constant force -- obviously it doesn't break. However, this would disturb the internal configuration. If I let go, then eventually the internal configuration would return to what…
73
votes
2 answers
Why does dry spaghetti break into three pieces as opposed to only two?
You can try it with your own uncooked spaghetti if you want; it almost always breaks into three when you snap it. I am asking for a good physical theory on why this is along with evidence to back it up. Or, a reference to a good study previously…
David Ball
- 1,137
35
votes
3 answers
Clarifying the actual definition of elasticity. Is steel really more elastic than rubber?
Yes, I know it's steel. It's everywhere on the web and I did google. But I seek enlightenment.
My physics textbook defines elasticity as:
Property by virtue of which a material regains its shape.
Or, the ability of material to resist change in…
sarthak-ag
- 551
34
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8 answers
What is the difference between stress and pressure?
What is the difference between stress and pressure? Are there any intuitive examples that explain the difference between the two? How about an example of when pressure and stress are not equal?
Armadillo
- 1,505
31
votes
3 answers
Why is stress a tensor quantity?
Why is stress a tensor quantity?
Why is pressure not a tensor?
According to what I know pressure is an internal force whereas stress is external so how are both quantities not tensors?
I am basically having a confusion between stress pressure and…
geek101
- 715
22
votes
4 answers
Why is the stress on a body not a vector?
In my textbook, Physics, Part II—Textbook for Class XI, there's a line which talks about why stress is not a vector:
Stress is not a vector quantity since, unlike a force, stress cannot be assigned a specific direction. Force acting on the portion…
archie
- 395
22
votes
11 answers
How can a physical quantity be neither vector nor scalar?
I was going through the definition of stress. I came to know that stress is a tensor quantity. When I checked the net about - 'What is a tensor quantity', I came to know that it is neither a scalar quantity nor a vector quantity. So how can a…
convexhull
- 347
22
votes
1 answer
Why does a flat sheet roll back into a cylinder when having rolled it once?
For example, if you were to roll a piece of paper into the shape of a hollow cylinder and then try to return the paper to its original, flat shape, it would naturally roll to the cylinder when you let go. Why would an originally flat surface, when…
19
votes
5 answers
How is potential energy actually stored in a steel spring at the atomic level?
Elasticity is one the most intriguing phenomena, wiki gives a summary explanation of what happens in a steel spring:
the atomic lattice changes size and shape when forces are applied
(energy is added to the system). When forces are removed, the…
bobie
- 5,862
17
votes
3 answers
Hollow Tube Stronger than Solid bar of same Outside Diameter (O.D.)?
I was listening to some co-workers talking about problems meeting stiffness requirements. Someone said that even with a solid metal rod (instead of the existing tube) we could not meet stiffness requirements.
I started daydreaming... and went…
Vintage
- 5,041
16
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3 answers
If we apply a constant perpetual perpendicular force on a brick kept on a floor, will it deform the brick?
Suppose a brick is kept on a floor and we apply a constant perpendicular pressure on it for an indefinite period, will it cause the brick to deform in any way?
Assume the pressure is small enough to not to break it immediately. Brick is brittle and…
SacrificialEquation
- 1,007
15
votes
4 answers
Why is the (non-relativistic) stress tensor linear and symmetric?
From Wikipedia:
"[...] the stress vector $T$ across a surface will always be a linear function of the surface's normal vector $n$, the unit-length vector that is perpendicular to it. [...] The linear relation between $T$ and $n$ follows from the…
R S
- 577
15
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6 answers
Why is stress defined in the way as it is?
Stress is like pressure and it doesn't matter in which direction the force acts (given it is perpendicular to the surface).
I read in my book that if we have a rope which is being pulled on both sides by a force $F$ , then the stress at any cross…
Ankit
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Dust patterns inside electronic product - what causes this?
(Note: another similar question from a few years ago yielded nought but speculation. I have at provided some detailed observations in the hope that the community can come up with something rigorous as an explanation...)
We disassembled an electronic…
Wossname
- 232