Weld Groups in Torsion or Bending: Finding Critical Shearing Stress | Primary & Secondary Shear

[@Nickilese]

Brilliance. You have made this concept crystal clear to me. The reveation that the segment of 48:30 to 50:26 has given me, has sincerely made my day. Thank you for ending my confusion spiral. God bless you.

[@TheBomPE]

Glad it was helpful! Thanks for watching!

[@mansour4378]

Thank you so much. Your contributions to science and free knowledge are appreciated from around the globe where you would have never even expected. Thank you again!

[@TheBomPE]

Thanks for your encouragement, and thanks for watching!

[@imafreespirit5872]

Man I went to the wrong college, I should have went to where this guy teaches. My professor took about the same time to give almost no conceptual understanding in comparison. Thanks for your help and giving an actually understanding of the problems!

[@TheBomPE]

I'm glad I could help out! Thanks for watching!

[@KokoMechE]

I like your sense of humor. You've been a great help as well thank you

[@TheBomPE]

If you found this video useful, consider helping me upgrade the old tablet PC I use to create these videos! Thanks! www.gofundme.com/help-replace-my-2011-tablet-pc

[@ehtishamhussain8852]

This guy is a saviour. Thank you very much sir.

[@TheBomPE]

I might help you save your time or your grade, but I reserve the title of "Savior" for someone else whose birth I celebrated a couple of days ago! I'm glad I could help in some capacity though! Thanks for watching!

[@nickgodden1980]

So glad I stumbled across your videos...now I plan on working my way through them. Thank you kindly.

[@TheBomPE]

I'm glad you are finding them useful! Thanks for watching!

[@alperturna4371]

Thanks for a clear explanation! this online education idea is better than the old school.. Especially if the instructor sucks, and you have to learn it by yourself...

[@TheBomPE]

I'm glad it was helpful! Thanks for watching!

[@HafidRecords]

Thank you!. It helped me a lot!. Greetings from Mexico.

[@TheBomPE]

I'm glad it helped! Thanks for watching!

[@smshaheerr1462]

Thank you sir. I was very much very much confuse in torion and bendign and to differentiate them but this give the idea.

[@TheBomPE]

I'm glad I could help! Thanks for watching!

[@AJ-et3vf]

Thank you very much sir! Lots of insights regarding dealing with torsional or bending problems that greatly helps with the conceptual understanding of the problem.

[@TheBomPE]

Thanks for the encouraging comments! I'm glad you're finding the videos helpful! Best of luck and thanks for watching!

[@dogansahutoglu2073]

Thank you, Big help on weld groups in bending and torsion.

[@TheBomPE]

Glad it helped! Have you taken your exam yet?

[@raretapes8057]

Can I please transfer here? My professor just dumps 50 slides with no real examples or simple explanations… every week. These lectures here are EXCELLENT

[@TheBomPE]

Come on over! I teach at Louisiana Tech University in Ruston, Louisiana! Thanks for watching!

[@shaneable1]

Thank you so much! Great videos and they have helped tremendously as I prepare for my P.E. exam. The university system might not survive if you keep posting videos like this though. haha

[@newmanhiding2314]

59:30 Should the primary and secondary shear stresses not be parallel to each other? If we’re looking at the throat plane of the weld, I would imagine the primary and secondary internal forces on that surface would need to be in the same (or opposite) direction to react to both the shear reaction and the moment reaction. If we were looking at the plane parallel to the wall, the internal forces (and therefore stresses) would be perpendicular, but we’re looking at a plane 45 degrees from the wall. The forces should be in the same direction, right? If the stresses were perpendicular as 59:30 seems to suggest, there would be an internal force pointing in a direction where a load isn’t being applied. I think I’m missing something.

[@abdullateftobaigy6499]

thank you, helped me a lot .

[@TheBomPE]

I'm glad it was helpful! I have two courses that I teach out of this text (Shigley), and I have a good number of videos presenting this material, organized into these playlists: MEEN361: kzbin.info/aero/PL1IHA35xY5H5AJpRrM2lkF7Qu2WnbQLvS and MEEN462: kzbin.info/aero/PL1IHA35xY5H5KqySx6n09jaJLUukbvJvB Check them out if you are interested! Thanks for watching!

[@Jake_Ritter]

What do I compare my total stress value to? I'm using E70XX electrodes but I'm not finding any equations for converting the 70ksi to a phi*Rn

[@louismouton9193]

This helped so much, thank you!

[@TheBomPE]

I'm glad it helped! Thanks for watching!

[@davidrjoseIFC]

Awesome class, as always! Let me ask you something: the axis where the bending moment is applied is the centroidal axis of the weld group?

[@TheBomPE]

Yes, that is correct. It is because applied shear forces applied at the centroid of the weld group will result in no net moment felt by the weld group. If you have an eccentric force, it can be converted to an equivalent force-couple system centered at the centroid.

[@manaswinisaikatragadda6241]

Dear sir: Why are you using Bending moment equation for finding out the secondary shear stress ... in my knowledge, we have to calculate flexural stress using MC/I and shear stress(primary due to axial force and secondary due to torque) and use any failure theory like DE criteria . if we use DE criteria we get 20.8Mpa which is more conservative than 20.34Mpa.. can you please clarify .. i am following all of your lectures .. you are really great sir..

[@MuhammadAhmad-yu9kv]

i dont think DE criteria is more conservative but it is more accurate. I calculated the stresses using different theories (MNS,MSS and DE) for other problem i got the maximum stress.

[@DhruvSharma0417]

Hi, why don't we use VQ/Ib transverse shear stress in addition to normal shear stress due to bending moment? V = 2kN here.

[@akoss242]

Thanks for these videos, very helpful. On the bending question, why does the denominator for primary shear use 1.414 instead of .707 and why is only half the weld length used?

[@itshabib5926]

Thank you so much for all the effort that you are doing and all the videos, you are helping a lot. Can you do a video about welding groups in 3d systems ? For example, if I have welds that are on x, y and z axis...

[@TubaChair3]

Fantastic lecture! Is there a method for finding critical shear stresses in weldments that are loaded in both bending and torsion at the same time?

[@yagzozgor7043]

Yağız Özgör 1 saniye önce Dear Sir, for the second problem, why we dont use here for a stress element in weld, which is described from mohr circle taumax, where sigmax=20,1 Mpa from bending and sigmay=0 and tau xy from shearing: 3,143Mpa. in the example you combine the loads not same with taumax which comes from mohr circle. there ıs a different. Because if you combine the loads with stress transformation formula ( from mohr circle) result is 10.53 mpa. but in the example result is 20.34 mpa.

[@beoptimistic5853]

kzbin.info/www/bejne/rHenfpR-hpmejZo .💐

[@cogitateandabet]

Thank you, professor! But I've got a question, as you've drawn here 22:36, is the direction of secondary shear stress alright? Shouldn't it be according to the direction of the in-plane torsional moment?

[@TheBomPE]

In this example I showed the weld stresses as reactions against the applied force. Doing it like you are saying is ok too, as long as you are consistent with how you represent both primary and secondary stress. Thanks for watching!

[@cogitateandabet]

@@TheBomPE I guessed the same but had some confusion. Thanks for making it clear, professor!

[@herohondapakistan]

Thanks for the informative lesson. Please mention the book referenced in the video

[@TheBomPE]

I teach this class out of Shigley's Mechanical Engineering Design, 10th edition. Thanks for watching!

[@theworldofvlogs5828]

THANK YOU SIR

[@TheBomPE]

You're welcome! Thanks for watching!

[@kingdemon4236]

Helpful Video, Thank you! Although I have a slight confusion, as I recall Mc/I is the formula for finding normal stresses due to bending but in case of welds we are using it to find secondary shear stress, why is it this way?

[@TheBomPE]

Secondary weld stresses are due to reacting against a rotational influence like a moment or torque, therefore Mc/I leads to a secondary stress. The reason it is considered to be a shearing stress is that a conservative assumption/technique is to assume all stresses carried in welds are shearing stresses in the weld throats. You might check out this video where I discuss that assumption: kzbin.info/www/bejne/bZ3UqZx3j76EqpI Thanks for watching!

[@kingdemon4236]

​@@TheBomPE The confusion I am facing is that despite taking the throat area and considering shear stresses in welds, there are cases when the attachment metal (and attachment line) has a more critical scenario than the weld, my assumption was maybe if the strength is enough to survive the maximum shear stress in throat area then we don't need to check anything else but in Example 9-3 the author designs the weld length based on attachment metal (taking the attachment area) calculations.

[@Manojkumar-hi5wt]

Dear Sir., Please share the book which you are referring for formulas in this video..

[@TheBomPE]

It is Shigley's Mechanical Engineering Design, 10th edition. Thanks for watching!

[@williamcase426]

yea buddy now I'm gonna weld some stuff up

[@ameamehaa]

for bending... Mc/I... did the c same as r ?

[@han34han34]

no. zero relation.

[@rahra6893]

Hey Michael super helpful lectures!! If you r thinking of moving from ur current uni , pls move to Australia and lecture at UoW wollongong, Currently v r facing some real trouble in engineering design subjects. (ps: Don't get fooled my profile name . I'm a real person)

[@TheBomPE]

Thanks, I'm glad they help! Would there be any possibility of a short-term position there? I would love it if it could work out where I could take a leave of absence from here for a few months or a year and teach there for a while.

[@rahra6893]

@@TheBomPE Sweet! I'm not entirely sure abt the vacancy but I kno our actual designing lecturer is no more in the uni. Shoot ur shot! www.uow.edu.au/about/jobs/sessional-teaching-and-casual-jobs/

[@tawfiksharbaji3814]

thank you too much

[@TheBomPE]

I'm glad I could help! Thanks for watching!

[@fandiks]

bagus banget guys

[@TheBomPE]

Thanks! And thanks for watching!

[@nalin8050]

48:49

[@aliarslan2086]

love from pakistan

[@TheBomPE]

Thanks!

[@ayushsinghal7315]

professors lecture is better than this and believe me nobody wants to study under professors in India.

[@TheBomPE]

I'm not sure I catch your meaning. Would you mind clarifying?