purdueMET not sure if you check this channel anymore but I just wanted to say thanks for all the tutorials! They really help with my mechanics courses and are the best tutorials out there. Thanks Mark :)

This is video I've been looking for the entire time. Such a great explanation.

You are 100 times better than my prof I am paying. Thanks boss!

Greatly appreciate the Instructional videos. I'm enjoying Mechanics of Materials more now thanks to this!

Missed only 10 minute of lectures. Came home and looked at notes and book for 1 hour. Had no clue what's going on. Searched online and this video surely helped understand this section.

if you want the element's rotation to be the same as the the Mohr's circle rotation direction, the positive shear axis should be pointing downward.

Hi Mark, All your videos have been extremely helpful to me. I really appreciate your time and effort. Please do another video which explains how to calculate the angles for 3D Mohr's circle examples. That would be really great! Thanks again Sam

you are a life saver. i love your videos. thank you so much

Thank you so much! I have a final tomorrow and this was the last concept that I wasn't too confident about....

your mohr's circle videos are great our lecturer explained it in a far more complicated way than you did thank you so much i appreciate all the great effort you put in these videos and like your shirts :P thanks again !

@gcass02 I am indeed a little busy these days, but am always planning more videos. Stay tuned for new ones. I'm glad they are helping you in statics. That's the first of the classes that teach you how to think like an engineer. Booyah!

Thank you, you are our hero

even though the video is 7-8 years old, it's still helping me. thank you. are you still making new content?

cool! I like it! Thanks you professor.

how can i find a principle stress solution from any stress tensor in the 3D space? or, say, how to rotate arbitrary "box" to meet the principle stress "box" by using Mohr circles?

thumbs up if u think he's the coolest solid mech and statics prof ever ;)

How do you know when to use or draw the mohrs circle? Is it when you have shear stress & normal stress at a point?

How about when you have to find the 3d stresses with eigenvalues? there are times when you cant use the typical equations but I dont know when any help would be appriciated

Yes, time is indeed the fourth dimension. Thanks for the reply.

How about when sigma 3 does not equal zero? Can you still find the principal stress' graphically?

@ermembro

10 жыл бұрын

you do the same thing, and sigma3 is non zero, nothing change.

Thanks a lot sir ! Can you give us an example how to find directions of principal axes n1,n2,n3 with Sigma 1 , 2 and 3 different from zero ? Thanks again !

how to decide whether we need to rotate 22.5 degrees clockwise or counter clockwise

@CallmePete89 The sum of the three stresses acting on the element MUST equal the sum of the three principal stresses. With enough information you can draw a 2D Mohr's circle, find the two principal stresses from that one circle and using the newly found principal stresses you can plug them into the equation where the sum of the experimental stresses equals the principal stresses.

Thank you sir

@2007063 Wow. You are most welcome - RMF

if you assume that the 4th dimensions is time... I have no idea.

you just draw a circle where the minimun value is 24 or -24 and the maximum value is sigma 2, then draw another circle from sigma 3 to sigma 1 and the half of that will the maximun shear.

What happends when sigma (3) does NOT equal zero? say sigma (3) = 24, or -24. Thanks!

sir can explin strin at a point ples sir

My prof uses powerpoints... this is teaching prof...take a note

HAHAHAHAHAHA look at his shirt "Mathematical advisory, Graphic content" then a bunch of graphs lmao

brennan cant pass

THis is not For a 3d !!!!!! its a 2D ..

@JohnSmith-zh6yk

7 жыл бұрын

no, It is 3D but the stress in z direction equals 0.

Fantastic video. Really really useful. You make things seem so simple and understandable. You have my thanks.

That video made this concept so much more clearer. Thank you very Much :-)

OMG!!! awesome. I understand your teaching. thank you.

Thank you so much Professor! An old student from Brazil!

0.0 if only you were a woman my age who could have told me all of this you would be perfect. This mini tutorial just saved me hard on this assignment I have!

Thank you so much! You are so clear!

I like how he throws those damn magnets on the white board!

So THIS is what it's like not having an illegible chinese teacher for one of your fundamental engineering courses. Thank you for posting this.

Thanks a lot !!!! Finally under stand what is going on!

Excellent Teacher! THANKS!! :D

YOUR AMAZING! thank you very much.

@Zenjoksss No problem. Glad to help.

thanks very much - great video

I'm dumbfounded! An American using the world standard measurement system! :O Great video by the way!

I do not quite understand the rule of thumb regarding tau-xy and tau-yx. Here tau-xy is 50 MPa. Is this not in the direction of the vertical arrow with only half an arrowhead? As it is mentioned tau-xy is the shear stress on the x-face in the y-direction and tau-yx is the shear stress on the y-face in the x-direction. But the arrow for tau-xy points in the negative y-direction and the arrow for tau-yx is in the negative x-direction. It confuses me a bit. So tau-xy is positive in the negative y-direction? And if tau-yx is -50 MPa in the negative x-direction then tau-yx is 50 MPa in the positive x-direction?

this was really helpful. But how do you use a tension matrix into a mohr circle ?

12:59 did he mean "assuming that I have plane stress"? why would you need to assume you have plane strain? Fantastic video btw :)

Great video thanks! Would have been even better if you had a voice recording device.

What happens when I got negative sigma3? How do I drow them? I got : Sigma1= 14.4 Sigma2= -4 Sigma3= -6.4 Kind Regards

So Iam wondering if sigma 1 and sigma 2 have to be bigger than sigma 3 in all cases ?! Or this is only when both sigma 1&2 are positive ??

@punkson

9 жыл бұрын

For plane stress, which is what we are doing here, you can plot the first circle then you have two principal stresses. The third principal stress then has to be at (0,0) for the condition where sigma z = 0. Either this is between the two so you can draw two smaller circles or it is outside the two so you can draw another small circle, then one encompassing both.

Is a 3d Mohr's circle equivalent to a VonMises stress calculation? Couldn't you draw this this "3D stress" graphically as a sphere? To draw this as a sphere the Sigma XY normal stresses would be represenated by the X axis of the graph as shown in this video, the Shear stress would be still bre represented by the Y-axis also shown in this video but the Sigma XZ normal stress would be represented on the Z axis of the same corordinate system. The sphere's outside surface is extreme condition

what if sigma z is non zero?

@mohammedalameri4763

10 жыл бұрын

Then sigma x or y should be zero, because we are talking here about plane stress. and in plane stresses we have to assume that one of the sigmas is zero

@mechanicalengineer7329

9 жыл бұрын

537jaga this is the question ^^ ....

Dont let your head be a Mohr's circle of stress

What if we have a 4-D ?

@CallmePete89 ...i guess the problem becomes complicated and is difficult to solve.so,we use a computer or something like that to solve it...and also i have never seen problems in which sigms(3) not equal to 0...in some standard textbooks...so that might not be a very important case.

FUCK YEAH! NOT GOING TO FAIL ANYMORE

It was all about 2D Mohr's circle, where is 3D ?

adamsın insansın

It's time for KZread University and I want you to be principal. It's quite funny that I can find better and more efficiënt explanations on KZread than TUDelft can provide me with.