Understanding Failure Theories (Tresca, von Mises etc...)

Failure theories are used to predict when a material will fail due to static loading. They do this by comparing the stress state at a point with material properties that can be easily determined from testing, like the yield or ultimate strengths of the material determined from a uniaxial test.
In this video I cover some of the main theories for ductile and for brittle materials - Rankine (maximum principal stress theory), Tresca (maximum shear stress theory), von Mises (maximum distortion energy theory) as well as the Coulomb-Mohr and Modified Mohr theories.
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The Efficient Engineer is a channel aimed at mechanical and civil engineers. The mission is to simplify engineering concepts, one video at a time!
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[@leoads]

I'm strucutral engineer with 20+ years of experience, and I wish I had an explanation like that when I was learning.... Took me a lot of time to fully understand, and I'm still learning. Congrats, very good.

[@TheEfficientEngineer]

Appreciate it, thank you!

[@jamesward2141]

I came here to write the exact same thing. The explanations around the failure criteria are excellent.

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(kinda) same here Google, youtube and internet in general are making a silent revolution in the field of didatics and studing. Those things used to be secret codes that virutally no one understood (well, not those ones here but some more advanced ones) Internet is slowly making knowledge, even advanced ones, democratic. I see mankind moving faster now that those information are more available and well explained

[@mrmadame28]

Have you ever use this once since school?

[@leoads]

@@mrmadame28 yes, a little

[@xl600mine]

I paid far too much to my university for Engineering Courses that were no where near as educational as your videos. Thank you!

[@sukursukur3617]

Actually they provided you to understand content of this video. But when we look at it from another angle, you are right. You shouldn't have learned new things about a topic that was finished studying decades ago.

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@@sharana.p5921 He is from Turkey

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Soooooooo true!!!!

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Paid to university doesn't mean the university has to read the book for you.

[@danguee1]

I'm a structural engineer in my early 60s. I have never seen or heard this subject explained better than this. Too often in text books, the text is written by experts who don't understand the need to explain this progressively from simple to complex - they just go for the final, complex solution straight off. And so, the subject matter starts somewhat impenetrable for many beginners....

[@lautoka63]

You must be my brother from another mother: I'm an involuntarily retired aero engineer of the same vintage, with a structures background. I wish I'd had this 40-odd years ago.

[@majermike]

im a structural engineer too, same thoughts, spectacular video, great editing, sound, graphics, music, holy crap the whole presentation I couldn't believe my eyes

[@amersabitovic203]

They write the books intentionally incomprehensible!

[@majermike]

@@amersabitovic203 certainly seems like it. why do you say so?

[@amersabitovic203]

@@majermike corruption.

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[@physicslover1950]

As you said you are a teacher . Can you answer my one question ? If the pressure of the fluid varies with depth assuming the density to be constant, should the temperature also increase with depth in a fluid? I think yes. See the atmosphere above us a good example of it.

[@robertbrown5129]

@@physicslover1950 there is no relation of variation of temperature with depth . Think about ocean water as its top layer has high temperature than the water in depth bcoz of solar radiation . As we goes in depth water has less exposer of solar radiation bcoz radiation can penetrate in water upto a depth . When it comes to earth Atmosphere the atmospheric layer near earth has high temperature bcoz of reflection of radiation from earth and then greenhouse gases like water vapour , CO2 do not allow them to escape which causes increase in temperature of earth near layer atmosphere

[@ShauriePvs]

@@physicslover1950 by the way atmosphere doesn't have uniform density... So you can't compare the almost uniform density scenario of water and highly varying density case of air

[@अण्वायुवरीवर्त]

@@physicslover1950 that's a very vague question there are many factors to consider here, By basic definition temp is measure of thermal energy which in turn is in case of solids and liquids is oscillations and in gas degree of random motion. Even more important is the fact that these changes in density of liquids are negligible with depth almost 2-3% you are comparing two different fluids with each other. Air is way different than water. And in the first place how did you manage to think that way? That temp would increase if pressure or density increases?? State eqn, I assume like ideal gas eqn, then its not applicable for subcooled liquids and I could even argue that Bcz we move air so much near the surface of earth the temp of air is higher, you get the point. I'm not even talking about radiations Whatever keep thinking, it's a good thing.

[@physicslover1950]

@@अण्वायुवरीवर्त Thanks for the motivation actully I got the answer 2 months ago that the temperature doesn't increase down with the increase of pressure because if the temperature increased then according to boyles law volume must increase and if the volume increased the density of the liquid becomes less than that on the surface which is a vogue and non sense statement 😅. Actually the density decreases as we go down . Pressure =(constant)(density)( temperature ) So in this case the increase in pressure is only due to the increase in density and an increase in density is due to the dcrease in volume . Recall again the equation PV = nRT Or PV= T When pressure increased with depth the volume decreased and temperature remained constant and wise versa. In case of earth the temperature increases down due to non uniform gravitational field. But in case of a swimming pool the gravitational field is nearly uniform.

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My professor loves to play efficient engineer videos during our lectures.

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i wish i had a professor like you.

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Actually, you have him as professor every time you watch a video of him.

[@jean-baptiste6479]

I too. I definitely did not become an aerostructures engineer, but an avionics one.

[@BoZhaoengineering]

I remember when I do FEM analysis using a software, these failure theories are present at the handbook/users’ manual of the FEM software. It is very nice to see the interpretation of these theories here. You did a great job. Thank you.

[@BoZhaoengineering]

I would prefer you denote the stress component in matrix than presented in plane shape/circles. According to matrix theory, any stress exerting to micro cube must be linearly transformed to the new basis, presented by the matrix. It is just my opinion at this moment.

[@Alekeser]

Bo Zhao shut up dude

[@jerin3710]

can u send me the user manual

[@andresgaviria9559]

@@jerin3710 what software are you using? During my school years I used Ansys, it's a decent FEA software. Find it in torrentz or google it. Usually, schools provide one, but it skips many steps.

[@Tunechi65]

@@andresgaviria9559 Ansys is what we use professionally. Atleast in the aerospace industry

[@TheTurmericTrail]

In my 20 years experience I never heard a much clear explanation/presentation of these concepts. Great effort and very good job.

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I study structural engineering at the highest ranked (by MIT) engineering university in Europe, and you just explained this particular subject much more clearly and in 1/6 of the time that the lectures took.

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[@florianrudowable]

I often come back to these videos to remember what I learned in my studies. It takes a lot of work and understanding to summarise the theory so neatly. Thank you very much for this.

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Mechanical Engineer for 5 years and I have been going over finite element analysis so I wanted to review this but didn't expect how much it helped. Like others before me, I am grateful for a much better my understanding is then I had before

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Yes exactly.

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That's a great comparison

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The animations are akin to those typically seen in Grant's videos. I'm betting he (or his team) uses Manim...

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@@ADickIHave If you've used Manim, you'd know that's not true. Manim is SPECIFICALLY for animating math. I think this guy uses Blender for the 3D objects and something like After Effects for the text/graph animations

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Soumil Sahu your guess is definitely smarter than mine. I have manim but don’t know the boundaries of its capabilities because i’m a grade-a amateur

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[@GamingShiiep]

Geoscience masters student here. I REALLY appreciate the visuals and the basic explanations. Sometimes our professors just jump straight to the more advanced stuff, without even explaining where the yield surfave or failure surface come from. Or it's really not well explained and no visuals were used. This channel is gold

[@tahinafelisca4324]

The graphics are amazing and really helped me understand why the yield surfaces look the way they do!!

[@sigmunddogbert7418]

Congratulation! This is the most comprehensive animation and visualization about failure theory I know! It reminds me how unbelievable it was to hear that hydrostatic stresses, no matter how high, do not cause plastic deformation. Also, you did a great job with animating the theories in principal stress space!

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This was pure art.. Stress engineer for 10 years... I wish I saw this 11 years ago. Good show.

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Be a Patreon

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[@TheEfficientEngineer]

Haha thanks!

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This was one of my favorite courses, especially because we got to learn the basics of designing things.

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I've been school & studying Engineering for 7 years, and now I'm just figured out the detail of Stress theory by this 16 minute video. Thanks! That was great explanation! Also the video really help for giving visual understanding!

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All the dislikes are from professors that can't explain these

[@ericfang8103]

I'm an engineer from China, once worked in almost all continents for nearly 40 years, thumbs up to this video. By the way, the monotonous tones of my university lecturers drove me out of most classes, I had to spend most of my time in library to learn by myself. Fortunately for me, Chinese government then paid almost all my education.

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This is by far the best explanation I have ever seen on this topic, amazingly well done and deep understanding is achieved with your method

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This 16 minutes of video made me understand what my university teacher couldnt in 1 week

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Man , you are the einstein for us mechanical engineers out here,!!!...🙏

[@Guywiththetypewriter]

Can I make a suggestion? As a student, information like this is invaluable. But , for those wanting to look further into the topic, having references to where you got this knowledge from would be most helpful. :)

[@Big_Slick]

Theres a million text books that cover these topics but try shigley's ME design it's pretty good. Videos like this are great for animations and bringing concepts together but if you really want to master it you should invest in a quality text book

[@elahesoheili8776]

I wish I could see this video sooner it was more helpful than all those university courses

[@Chatterjeepal]

Thanks for this visual aid, I'm gonna be taking the FE (other disciplines) this August and I know learning this theory will help me a bunch.

[@paulanhalt3609]

Wow, this is the first time that I can say without doubt you explained these failure theories, where they came from, and the differences between them far better than I was taught in college. Thank you very much for making these videos and I really give you props for your deep understanding of so many topics

[@ankursharma-bg5mr]

whenever I watch your videos I just go into another world

[@varunpoojary]

Great explanation. Looks like this is going to be one of the top engineering channel on KZbin very soon. The amount of hardwork you put in this video should deserve it.

[@patrykserkowski7564]

The true is that the first to develop the theory of stresses and strength was Maksymilian Tytus Hubert (1904), the second Richard Edler von Mises (1913), the third was Heindrich Hencky (1924). James Clark Maxwell (1865) - main assumptions in letter. Eugenio Baltrami (1885) - concept. So, in the foto should be Huber or each one of them 😌

[@AzT97dmeTd]

I am starting my Masters in Solid Mechanics / Materials for stress state dependent failure of ductile metals, and I could not be more grateful for your solid mechanics videos. Thank you!

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Hey ! First of all thanks for your educational videos, they're truly amazing! Maybe you could make a video on Beam Theory ? Keep it up!

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Where have you been all my life. I'm watching all of your videos now, as this is the best explanation that made the codes and standards I'm using for work easy to assimilate. Thanks for this beautifully explained tutorial. I'll give anything to be a lifelong learner from you.

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Me clicking on this video: "I have a degree in physics, whatever it is, I'll understand it." Me after watching the video: "There is nothing about this I understand."

[@passerby4507]

You're just being screwed by jargon. Abstract reasoning-wise, there's nothing that's demanding in structural engineering comparable to physics.

[@jakewagner7416]

@@passerby4507 I definitely would be aided by understanding the terminology. The math didn't seem overly complex, but the stress/strain "phase space" things seemed really cool.

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This required a substantial effort to produce and I for one very much appreciate it

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I've just invated all my students to come see your videos.

[@TheEfficientEngineer]

Thanks! :)

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I have no words for your presentations and content. It will take learning to different world.

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Yo soy mexicano y para mí es complicado leer los subtítulos y observar al mismo tiempo las imágenes y gráficos. :C Espero algún día tengas tus video con audio en versión español, créeme que mucha más gente te vería, y hasta tendrías el doble de suscriptores, espero lo tomes en cuenta. Tus videos son grandiosos!!, pero a nosotros nos cuesta el triple de tiempo entenderlos a la perfección. Saludos.

[@msdesf]

The most comprehensive and understandable explanation of all time. Thanks a lot!

[@willj78]

Where was this a month ago, my professor didn't teach it anywhere near this well!

[@RicardoSousa77]

I am an instructor on Solid Mechanics and definitely will recommend it to my students. Superb graphical details, congratulations on the job done

[@satyamsurawase4872]

Awesome videos sir thank you so much for this Can you please suggest reference book for learning mechanics of materials for mechanical engineering , i want to develop concepts like you . Thank you in advance sir 😊

[@ayonaki]

The fact that you put this much effort is mindboggling. I am currently doing this course and this really helps out a lot. Thanks!!

[@vishnuraj6227]

Sir, can you do a video on Margin of Safety and its significance

[@atifismail391]

It was one of the best tutorials I have ever seen throughout my teaching and student career of the last 12 years...Thank you for your efforts.

[@rabinsonrai2905]

I really loved your work. What book would you recommend for learning the significance and particular case for the appliance of the theories for a beginner in the field of structural engineering

[@npnk916]

Mechanics of Materials - Ansel C. Ugural is an excellent book and has practical case studies on several applications

[@joaolacerdaoliveira3896]

You've just summed up 6 University courses and over half a year of my life in just over 15 min, I'm not sure if I'm happy or frustrated about this but A+ on your efforts 👍

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Awesome. I am a doctoral student, and found your videos amazing. Super easy to understand, but extremely effective. Many thanks.

[@aasifshah2331]

As an instructor of continum mechanics I have never been able to find such a lucid explaination of the concept. You are doing a job par excellence. More power to you.

[@iftikaphilowardani147]

Seriously..this explanation helped me much...when i learned about this i cannot put the red string between stress, mohr, failure theories..but connected all information so i can understand better..gud luck..love this channel so much

[@jamesward2141]

I’ve been a stress engineer my whole engineering career and can’t believe how useful and concise this whole KZbin channel is. I’ve only stumbled across it today but am amazed by the quality of the content and the explanations.

[@TheEfficientEngineer]

Thanks James, that really is great to hear! :)

[@525guy]

Man, I wish this guy was my professor using these animations in class! I'm a visual learner and these animations helped better than any TA or office hours that I went too!

[@edgararturogomezmeisel2217]

Very well explained. I have seen University lecturers not being even 10% as clear as you are. Nice images too!!!

[@camiloandresromeromendez5891]

I am currently working in an investigation of a train derailment accident (with no fatalities) which happened to have a level of damage on the train's safety structure, this video has been really good to refresh my mind on the terminology used in many of the different reports and simulations that I had been reviewing. Very much appreciated !!

[@TheEfficientEngineer]

Sounds like an interesting project!

[@jacopodigiacomantonio3103]

i remember this topic coming into my engineering classes as a tornado destroying all my motivation, being explained by professor in a so inaccessible manner that made me feel like “i’m too stupid as an engineer that cannot understand materials physics, that is why i am bounded to management engineering” … after i guess 3y now, i am fully master graduated engineer but only after this video i saw how straightforward and pretty logical this concepts are if presented with the aim to let people understand, especially when u extended on the 3-axis the 3 failure theories for ductile materials. As Einstein said “The definition of genius is making it simple” even if things are born complex and need to be assessed with rigor. Very well done and thanks.

[@morhunn]

One of the best educational videos I've came across in a long time. You got yourself a new subscriber.

[@paulbester1571]

Bloody hell bruh i sat through 2 lectures of this stuff and you explained it perfectly in 15 minutes. You are doing amazing work, please do keep it up.

[@alyax2026]

Oh my god, you're explaining so well these concepts. My compliments!!

[@bijubalakrishnan6414]

Great visualization of failure theories. I watched this many times to understand better. Every time I learn some thing new which I never paid attention to.

[@eyeHATEuall85]

Never been to College in my life! Didn't need to be. I've understood structural integrity/failure since I was a kid. In 9th grade, I won the Bridge Strength contest when we were tasked to build bridges with these super soft matchstick-like pieces of wood. You were only allowed so many pieces and so many glue points. Then after a day of drying, it was on to the testing. The substructure of my design held 212lbs. I still have that bridge. As I grew up, I started noticing similar designs and the same design being used everywhere. I believe I went to school stoned that day. I have severe ADHD and was on Adderall. So basically, my brain slowed down enough to actually THINK through the task at hand and build what made sense to me. It worked and I WISH I would have pursued a career in the field. But I chose a different path... Awesome video, something actually worth watching!

[@wffff2]

This is so good I just have to come back and watch it every now and then.

[@deamonofshiva]

No book no matter how much acclaimed to be superb explains Failure theory like you. Wonderful explanation.

[@kishoreysn7801]

Only channel till date that has wonderful visuals of complex mechanics concepts. Thank you for such amazing content.

[@TheNostalgicWorld]

This is what we learnt in whole a semester of Engineering college...it is summarised very well...thank you🌞

[@abu-bakr9604]

You explain what took me years and years to understand in few minutes

[@BirnieMac1]

Between you and that giga-chad Sal from Kahn Academy; I don’t think I’d have made it this far through the degree without your videos

[@sanchitagarwal3471]

By far the best explanation of the failure theories that I have seen. Made my life a lot simpler.