this is why i dont go to class anymore. a long-winded 1 hour lecture can never beat a well-explained 6 minute video
@henzehe9 жыл бұрын
Bending a wire back and forth to break it struck me as a strange choice of example of fatigue failure. It is an example of repeatedly exceeding yield stress and repeated permanent deformation in a ductile material. When making a structure or device out of ductile/malleable materials the designer should almost always keep cyclic stresses lower than the yield stress (and usually non cyclic stresses too for that matter). Breaking this design rule usually results in a uselessly short lifespan. The value of fatigue failure analysis lies in its ability to predict if/when parts that seem to be working fine initially will crack. This isn't the case with the bent wire. A little research revealed a better analytical tool for the wire bending example exists; the Coffin-Manson relation uses strain rather than stress in order to predict failure in ductile materials that are subjected to repeated deformation.
@danpt20006 жыл бұрын
I think many people go to the metal wire as an example because many high school teachers use that. Which according to more experienced/knowledgeable people, is not really fitting for fatigue failure.
@josericardotarpani262 жыл бұрын
Have u ever heard about low-cycle fatigue? Probably not...
@tr90362 жыл бұрын
Actually it fits to example. High quality phone charger manufacturers claims that their cables lasts for 10.000 bends. Which means this video is a real life example and easy to understand for non expert people.
@Vrang8911 жыл бұрын
Wow. That was easier than I thought. Thank you for taking the time to make this!
@VirendraBG4 жыл бұрын
0:30 it's *Ratcheting* (cyclic load which results stress more than yield stress in every cycle) and I guess not fatigue. Fatigue is when cyclic load results in stress below yield stress in every cycle, but the system fails because of no. Of cycles. For example pressure vessels. Here is another explanation of fatigue. kzbin.info/www/bejne/pV6Zh5KApLeLZ8k
@jasonr56812 жыл бұрын
The best visualisation and explanation of fatigue i have seen thanks
@MegaShriyash5 жыл бұрын
Fatigue was beautifully explained! Thank you!!
@nilofarpathan6654 жыл бұрын
Thank you for the simple and effective explaination
@azhaafiikhsan78916 жыл бұрын
Perfect explanation. Thank you sir.
@AS-fm5ew10 жыл бұрын
great explanation ....giving a good physical understanding of what fatigue is.....
@Shaikhshadat11 жыл бұрын
awesome work man!!!!!! i respect your hard work :) plz keep uploading more videos, it is helping a lot
@peglor7 жыл бұрын
Materials such as steel and titanium have a fatigue/endurance limit. Aluminium and most other materials however do not, so it's not possible to design structures in these materials to never fail from fatigue. In this case the number of cycles must be set much higher than the expected number of stress cycles in service. Also the diagram is misleading in that it showed a crack forming and growing inside the material - in all cases of homogeneous materials without case hardening or similar surface property modifications, fatigue cracks always start at the surface.
@TheSunshineRequiem6 жыл бұрын
wow this is very good, you should hire someone to read it out loud though.
@omadhyaru77657 жыл бұрын
very good and practical view
@shridharacharya1345 жыл бұрын
Thank you sir for this valid video😊
@lekhrajdewangan84914 жыл бұрын
Finally after a long time I got its ans
@syedmuhammadtayyeb69943 жыл бұрын
!! The example of wire you have given isn't fatigue but it's strain hardening Because we bend the wire permanently that isn't the case in fatigue
@naviddavanikabir7 жыл бұрын
great video. I need to do this test on PEEK, a rigid plastic. the standard we follow is ASTM 7791. knowing only the ultimate stress and with limited number of specimen, how should I choose the stress/strain level to find the endurance limit and to waste as little specimen as possible?
@anuragchandnani80377 жыл бұрын
Great Video . Keep up the good work
@AS-fm5ew10 жыл бұрын
ur website is also awesome
@saiteja30194 жыл бұрын
Great video sir like upload videos of mechanical engineering sir
@lifewonder90335 жыл бұрын
Very useful video
@obadiahmaxwell88207 жыл бұрын
Good day. Please can you explain Double linear Damage (DLD) in contrast to Miner's Rule (Linear Damage)?
@MarkKRogalski10 жыл бұрын
Not all materials show an endurance limit, for example steel and titanium are the only two metals that have one.
@ahsabhasan41189 жыл бұрын
greatly explained ...
@jayasimhanrao32698 жыл бұрын
Very nice presentation. Thank you so much
@emrekaldrak7203 Жыл бұрын
nice video
@sriramsharma98984 жыл бұрын
please,make videos in civil engine...
@jwais36229 жыл бұрын
This is amazing thank you so much for the effort U put in this :)!!! Really appreciated!!!
@rudhajassim94695 жыл бұрын
ty
@christosdovles34618 жыл бұрын
this is really helpfull
@AS-fm5ew10 жыл бұрын
Sir please upload videos of Heat and Mass Transfer also please
@crazygirls44915 жыл бұрын
Why does soderburg line is most conservative??? Please reply sir
@Medhusalem9 жыл бұрын
It is wrong, that the material will never fail after reaching the "limit". It is just an assumption because not a high enough number of cycles have been tested. As seen in wind energy components where cycles are over 10^9 this limit is wrong and components are still being damaged by fatigue loads below their assumed limit!
@igcr12345678907 жыл бұрын
there could be coupling with other modes of failure, like wear, stress corrosion, etc.
@ikik94694 жыл бұрын
How can I calculate how long a machine with a given stress amplitude will break?
@asmaaaq516011 жыл бұрын
can you explain the creep-fatigue interaction?
@kymattok5 жыл бұрын
So if the stress is under the endurance limit is the material undergoing stresses that would be in its elastic range on a stress strain graph?
@prashanttiwari62145 жыл бұрын
Yes
@risingphoenix76708 жыл бұрын
why took log s vs log n graph?
@Kumarvikramgwl6 жыл бұрын
Both value s and n are exponentially changes when one of those value changes so log scale represents it better.
@MrSidney96 жыл бұрын
You get a straight if you do that instead of exponential curves
@SaiKrishna-vz1up8 жыл бұрын
Awesome
@sumitrode66709 жыл бұрын
superb!!
@atiqahmadjan91757 жыл бұрын
what is stress in physical phenomena ?
@주영-f5u5 жыл бұрын
3:40
@shashwatpandey13715 жыл бұрын
💯💯✔️
@bilalsara58095 жыл бұрын
Please can you add Turkish subtitles for other videos
@wahaajali10097 жыл бұрын
thanks alot bro!
@قيصرالمدينة10 жыл бұрын
shkrn lak
@parthbhide799211 жыл бұрын
really helped
@pvnp0076 жыл бұрын
Why we have to draw the graph in log
@MrSidney96 жыл бұрын
Its for convenience., otherwise you don't get straight lines.
@utkarshsrivastava9386 жыл бұрын
can anyone pleasr tell how can i convert rpm into no.of cycles
@rogeronslow14987 жыл бұрын
Nice content but the computer voice is horrible.
@tabaks6 жыл бұрын
Roger Onslow, go grab a cold one and get yourself some personality along the way.
@himg4digu6 жыл бұрын
U haven't 'seen' horrible then i guess :P, sorry i meant to say heard
@erickhumalo19135 жыл бұрын
You're a dumb ass dude
@AS-fm5ew10 жыл бұрын
awesomeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
@sln77366 жыл бұрын
Google translate
@Newbport8495 жыл бұрын
If you're considering engineering as a major, don't do it. It's not worth it.