Understanding Fatigue Failure and S-N Curves

[@petercalow1028]

HELLO, I have an exam in 2 and a half hours. Can you tell me why the initial fatigue results are scattered? Cant find the answer anywhere. Great video otherwise!! Thankyou!!

[@TheEfficientEngineer]

Hi Peter! Most of the scatter will typically arise in the crack initiation phase, where there is more variability, than in the crack growth phase. This initial phase will be sensitive to things like the surface conditions of the test piece. Of course there will also be some variability associated with the test, e.g. the equipment that is used. Hope that helps - good luck with the exam!

[@petercalow1028]

@@TheEfficientEngineer Ahhh yes, thank you so much for replying so quickly. Will need the luck!

[@Tranefine]

peter calow How did you do in your exam? :)

[@hamz4977]

hqhhahahHAHAHAHAHAHAHAHHAHAA

[@ashwinpande7095]

i cant believe he actually replied just in time before your exam

[@kingz.a1918]

my professor spent tens of hours to deliver what you have delivered in less than 10 minutes

[@babajungLA]

That's because the professors need to justify their jobs and therefore have to drag out lectures when in reality they can be explained in much easier terms as seen in the video.

[@ziheng666]

If the professor use the video method to teach u in the first time, May you not understand the content.

[@shakirobaid2895]

if you have no idea what stress is or what stress strain chart is or what fatigue is .. what stress amplitude is .. it could take a while to get here and for you to understand it .. however going through semester and thn filling up gaps in understanding from youtube videos work really welll

[@CluckYou21]

This guy spends tens of hours creating this video.

[@mikimikito-mc5mr]

This man is God

[@honzco]

I wish there was a channel like yours explaining engineering facts when I was an Engineering student. Complicated engineering concepts are easier to understand and remember with multimedia like your channel. Thanks

[@elnuryus]

+

[@aravindvissamsetty]

That was basically my entire Masters level Fracture Mechanics course condensed into just over 8 minutes. Great job!

[@mathiasbruunchr]

These vidoes are the best i have seen on the topic of mechanical engineering. Keep up the great work.

[@albanopietro3173]

What a video! That is one of the best explanations I've ever seen in my whole engineering life! Congratulations to you all! And, please, don't stop posting subjects like that

[@irtesamnasrat9866]

thank you for making the nights before exams this much easier. the graphics, animation, voiceover and the scripts are very well thought and well put down. please don't stop producing such useful video lectures, the planet needs good people like you. 🙏

[@ozgun228]

I love the efficiency in your videos. No need to waste hours to have a solid understanding of important principles.

[@bpring21]

I would love it if you kept making amazing videos. You do a great job breaking down the fundamentals without overloading in the theories behind them. The annotations...pristine!

[@GeniusEngineering]

I like how your videos explain these Engineering concepts in an understandable and visually engaging manner.

[@nareshvangari2021]

Randomly found a video.....In two days completed his entire playlist. Now addicted to his videos. Waiting for my bell icon notification.

[@sairaj7914]

Completing this video marked my reaching the end of your Strength of Materials playlist. What an intense but great wrapping up of all core concepts! I feel so much more confident learning this. I already work as a machanical engineer and this is seriously better than whatever I was taught (but did not understand) back in college.

[@samuelcarvalho3691]

Best Channel for understanding Engineering concepts. The visuals does the world of good.

[@The92gopal]

Hi. Huge fan of your service. It isn't easy to eat an entire sugarcane but it can be easily consumed as a juice. As part of an engineering community, we are grateful for your work. Can you please do a video on Fracture mechanics as a follow-up to this?

[@CaesarBro]

I had a poorly packaged pipe shipped to me crack from either reaching tensile strength, cycle fatigue, or both because it wasn’t strapped down and it was fully constrained at one end. So while riding on the truck it freely bounced up and down, like a spring until failure. Now I’m writing the FMEA report. Calculations showed it may have reached plastic deformation elsewhere if tensile strength was reached, let alone ultimate strength. Now have to measure crack size for comparison. Thank you for the useful review!

[@babajungLA]

I'm not even a mechanical engineer but my manager gave me a test report of a structural brace to review if it meets AISC seismic provisions...this video helped me so much to complete my review!

[@andrisberzins9053]

Great video introducing fatigue! Could mention that damage summation by Miner is only approximation as for variable loading actual loading history can make huge difference. Fun fact initial high loading (even partial yielding) for steels can improve high cycle fatigue.

[@cwong1229]

Thank you very much for the video!! After I watched your video, I realized that most of the professors at a 4-year research university don't know how to teach!!! I cry 😢 because videos like this didn't exist when I attended college. P.S. I graduate from college back in the year 2010 by the way. Back then KZbin was just 5 years old in my graduating years, meaning it was still relatively new, and learning engineering concepts from youtube back then weren't as common as today. There weren't that many videos that are educational and can teach me engineering either back then. All I can say is: college students nowadays are such a group of lucky fellows.

[@Sean-sn6gn]

Please never stop making videos. You are such a big help you have no idea!

[@joeymorse365]

I was stuck on an assignment question and just watching 2 minutes into this video I knew what to do. Thanks and subscribed

[@thesuperkat943]

On the stress amplitude graphs at 4:15, you should’ve plotted some of the other theories, especially since the Goodman line and Gerber Line do not guarantee infinite life, as they can fail from going past the yield point of a material, giving them finite life. This is true for most theories, but especially true for these

[@hz-vb6hn]

Man your channel is a treasure......I hope there were more channels like yours in different subjects

[@khaidirandromeda]

these is what i needed for so long, representaive animation, simple and easly understanding for those who are not english native speakerr, keep it up broo.. attending college cant make me understand about material engineering :') , may u blessed..

[@tanmayeheblekar2162]

Can't wait for the Strain Life video. Outstanding presentation of the concepts as always! Thanks a ton mate

[@sultanhassanieh7546]

Make a video on creep pleaseeee

[@aynilaydin4658]

The greatest video about this I have ever watched. Thank you so much.

[@miawmiawcat1838]

Your videos make me fall in love with engineering all over again 🥰

[@ambidixtrs7111]

Wow, a video like this can clear up the whole concept that one were struggling to understand during its semester. That one would be me 😅.

[@ShayanAsim]

I am super impressed by your way of summarizing the S-N curve. I was just looking for a video to refresh my concepts and this is perfect. Keep up the good work! Subscribed and expecting even more from you guys now! :D

[@8mybcur]

i learnt more in this video than i did in 3 weeks worth of lectures

[@mohammadkhanafer4847]

please , do not stop blowing our minds with this amazing videos, keep it up and you can really do much better and download more videos on different topics in engineering, man it’d be amazing for all of us in the industry

[@amiraboodi2075]

Thank you very much. This video helped me a lot to understand what is fatigue failure. Your explanation is fantastic.

[@hal9000svk]

Very good intro to problematic. Just what I needed. Thank you!

[@danielbadel1226]

This video and all your videos in general are really cool, educational and cristal clear. I wish you made a couple of lecture about LEFM and fatigue approach for multiaxial state of stress criterions or non proportional mixed loadings. Greetings and thank you!

[@alyafey69]

mannn than you soo much!!!! you really made it 100 times simpler than what my teacher was trying to explain

[@multifat8416]

Great explanation of fatigue phenomena in all their aspects, in a simple way. Thank you ! 🙏

[@belakhdarmedslimane8946]

Such a great explanation......We need an episode on VMEA/FMEA analysis

[@sher.5027]

This is completely Gold. Can't appreciate more. Thanks for making this. You will Reach 1M soon.

[@VinodKumar-vw8hf]

Thanks, very well explained with minimum maths. The graphics used is very good to make the viewers understand.

[@karthikpurushothaman418]

your videos are the best in explaining mechanical engineering concepts. Thank you

[@GamingShiiep]

I'm studying geosciences in my masters. I still can't believe how much of other disciplines we have to know (like engineering, physics and chemistry. It's insane.

[@jankafka6731]

Excellent job, very explanatory a easy to understand. I wish this had exist during my msc study 20 yrs ago. thumbs up!

[@vohoangquannguyen7706]

Hi, many thanks for the videos! It help me to get overview of the engineering methods regarding this topic!

[@jeysrether]

best explantion for fatigue failure thank you very much

[@benudharmitra9563]

Very simple illustration Bravo.

[@mangeshdeshmukh2140]

Superb sir , Greetings from INDIA !

[@jimvog1775]

INSANE FINALY SOMEONE CAN EXPLAIN SIMPLE IN 8 MINUTES

[@AkashDeep-st6ms]

Well explained video. I am grateful to you to make these difficult things so easy and interesting.

[@mouhamadmoustafa6538]

Amazing 👍👍 please keep it up, you're explaining the hardest topics in a very simple way !! Greetings from Lebanon

[@Damnfoolyt]

This guy deserves a billion subscribers

[@itsagoal182]

Endurance limit is king, and everything I’ve designed, where possible, has been within this limit. For steel, I try to design to Tensile/3 and apply a good surface finish, and touch wood I’ve not had a failure in over 20 years.

[@nyquist_control]

yup, factor of safety always important to use irl.

[@itsagoal182]

@@nyquist_control not so much a FOS with fatigue, but typically for steel, fatigue really only becomes an issue at Tensile/2, although there are mitigating circumstances!! That’s why working to Tensile/3 means your design is typically free from fatigue failure.

[@akhilpatil-jain7644]

The video is great n pretty crisp...keep up the great work

[@alexnicolas9486]

OMG this video just help me figure out the answer for my assignment question, thank you!

[@ngm_4092]

Fantastic Video. The concepts are explained in detail and in a clear manner. Graphics are outstanding enabling easy visualization. A wide array of topic attributes are introduced to aid in further exploration. Love this, keep up the good work.

[@Uzumaki998]

This playlist is great!!! Whenever i feel like revising my basics i just go though your playlists. Can you make some vids on manufacturing process and theory of machines...would be of great help

[@akshaypawashe7043]

Please please please please add more such videos and for complete mechanical engineering. I am requesting you🙏🙏

[@safooh94]

I like the quality in your video and your explanation. Keep up the good work 👍

[@nitishbarnwal3447]

U deserve millions of subscribers and their support. Please upload videos on Fluid Mechanics part too.

[@smith101.9]

my professor just showed this in its entirety during a lecture

[@elnaeemabdalla]

this video explain more about fatigue , thanks for this information

[@АдиКабиев]

I like explanations with illustrations! Thank you, guys!

[@saverrosuseno6712]

These videos are so good!! could you do one on stress concentrations??

[@luisatilano1]

You have an amazing channel here. Don't stop.

[@uditsaxena3844]

Thanks life is easy when u have good ppl

[@louisavelino9323]

Thank you so much! Sending good vibes for this.. Very well made video.

[@arunal5726]

Superb explanation..Thank you so much.................🙏🙏🙏

[@usmanwaheed3721]

Very Good Work Sir. May u always make such quality animations lectures for us.Thanks

[@LikhitK]

This has been a very engaging learning experience. Truly efficient!!!

[@mohammadhoseinrivandi5657]

I am totally grateful for ur videos!!! KEEP GOING!💥

[@thanusubramoniam1367]

Useful and simple presentation

[@vivekgupta9829]

Please make a dedicated video on low cycle fatigue

[@burakcnar5172]

Just excellent, buddy. I use your videos to freshen up or sometimes even clear the concepts up in my mind. Thank you. :)

[@mgh1598]

perfect informations.this video helps me a lot to remember . thank you bro

[@gussosa]

I am a Mechanical Engineer with 20 years of work experience. Only understood fatigue now thanks to you.

[@69erone-half50]

Understandable because it's a complex subject✌️

[@a1mforthetop]

normal loads don't usually cause fatigue. so it's not only complex but very specific as well

[@aravindvissamsetty]

More on fatigue please!

[@javier987]

I love these graphics! what software is being used?

[@AnilVerma-uh2np]

Simple and details explain action.. thank you...👍😀

[@bozhenwang5493]

wow, such an informative lesson!

[@sahandsoltanieh5186]

awesome explanation, awesome animation! Thanks a lot!

[@AbhishekKumar-pi8hr]

Very Well Explained

[@mmpatil08]

Very easy to understand

[@enjoymfs9715]

If you help me to understand that sitiuation, i would be appreciated a lot. lets say that we designed our mechanical part with minumum stress concentration. No initial crack, hole or something that inreases or causes stress concentration. What would be the key factor occuring fatigue failure ? since we dont have anything against stress concentration which will cause crack eventually. I have read some articles which mentions that stress amplitude is the reason of fatigue failure? Btw, you did a great job. Waiting a similar video regarding creep failure

[@BoZhaoengineering]

you explain it very clear! thank you very much! just more about rainflow counting method, in matlab there is built in function that give you the cycle number, range and mean of a complex fatigue record in time domain.

[@TheEfficientEngineer]

Great tip, thanks! There are also Python modules out there that can do the same, e.g. pypi.org/project/rainflow/

[@pavanvinay1874]

10 pages concept in 10 min 🖐️ thanks

[@DineshKumar-ts1vq]

Awesome. Thanks for putting your time and effort for this brief and elegant explanation. Expecting more videos from this channel. Subscribed :)

[@anon4286]

thank you so much, your explanation is so helpful 💛

[@Kornet104]

About so known 'endurance limit'. Actually there is no such thing in real life even for ferrous materials. It is shown that at number of cycles about 10^9 failure still happens (such numbers can be obtained in low-stressed high-frequency parts as gas turbine engine blades, reduction gear teeth and etc.). Look for 'Gigacycle Fatigue in Mechanical Practice' by Claude Bathias for the initial acquaintance. It is said at 3:10 that at low stress levels we are dealing with only elastic deformation, but this is a complete nonsense, because it contradicts the definition of elastic deformation (!). Nevertheless, I am very pleased with the quality of the material and am grateful for the popularization of engineering knowledge.

[@wonsuk307]

Great video! I found it extremely useful. Thank you, and I hope you make more.

[@hemanthtandaganagaraju2943]

Fantastic video, I have a question. At 2:06 , isn't the number of cycles to failure 600,000?

[@JoelRTLCosta]

Thanks for the videos. They're all great!

[@mohdabdulmukheet6125]

Please make a video on static theories of failure

[@tantran4152]

Thanks for great videos.

[@smeetashar]

Can you please suggest some books or material for further reading? And thanks for this awesome video.

[@TheEfficientEngineer]

Hi Smeet, glad you enjoyed the video! Dieter's Mechanical Metallurgy has a well written chapter on fatigue of metals that I would recommend as further reading.

[@smeetashar]

@@TheEfficientEngineer Thank you!!

[@BlackBox019]

Please keep doing these videos 😭

[@kashty103]

My material science instructor put the link to this video in his slides.

[@RameshRajesh10]

Thanks for the video.

[@shivanandsinghPCEME]

Great Explanation Thank you so much 😊

[@jugokadi8394]

Hello and many Thanks for this great video, I'm not mechanic engineer but I really appreciate ... the question is how the life duration can be estimated in case if in additional to the mechanical constraints there is also the thermal constraints.

[@pierrickcyrenne4904]

Hi! I am currently studying materials engineering and I am particularly interested in the field of fractography and fracture mechanics. Would you consider making a video covering these topics? Your videos have helped me a lot throughout my program and I would love to have one of your summaries fracture mechanics.

[@TheEfficientEngineer]

Hi Pierrick! I've been thinking about covering fracture mechanics for a while, and it's definitely close to the top of my list of future topics. Glad to know you'd be interested in it!

[@pierrickcyrenne4904]

@@TheEfficientEngineer You can be sure that I'll listen carefully!

[@manshi1028]

Hello, can you provide such videos on concrete fatigue failure as well.