Thanks very much for the video! Love the way you teach. Very clear and concise. can you do a vid that covers a UDL with a supporting wall to obtain the size of the RSJ?
Cheers mate, really helped a lot. But correct me if im wrong, this is the same as first calculating the shearing forces, drawing the SFD and then getting the BMD from that too right?
Hi Alissa, in analysis, we follow some arbitrary conventions to help to keep us sane. In the UK structural engineers draw bending moments on the tension face of beams, whereas mechanical engineers draw them on the compression face. You could consider clockwise moments to be negative or positive. The most important thing you can do when analysing moments is to be consistent and to clearly understand the size of any moments and to understand whether a beam is hogging or sagging. On this basis, I can’t say that you are right or that I am right, I hope that this helps, Mike
Hi Ryan Mallin, thanks for your comment and I am not surprised that this is the case, as the decision to call clockwise moments positive or negative is wholly arbitrary. I can only tell you the way that we do things in our university in the North of England. The key thing is that you are consistent and then when you draw the bending moment diagram you plot the bending moments either always on the tension face of elements (or, if you are not attending our university perhaps) on the compression face of elements. I hope that this explains the inconsistency a little, Mike
The way i see it.. the longer the distance from point A the higer the number.. does that mean the higer the load... Im trying to calculate the max load ot safe load on a Y truss that im usung to suspend ligting and audio equipment.... im usin I beams from global truss...about 6.5m long each seccion..
Hi ladjkoaz, Thanks for your comment. Generally, for a simply supported beam, the bending moments are greatest around the centre of the span. If I understand you correctly, you are designing a simply supported truss - this would behave, in some ways, similarly to a simply supported beam. As the bending moments are greatest around mid-span, the axial forces in the members of the truss will be greatest here as well. Good luck with your analysis and design
+Mike Bather Greetings Mike: The maximum bending moment for a truss would indeed be located at mid-span given the same loading condition as above, however, the axial forces of the truss members would not necessarily occur at mid-span unless you are talking about a truss with a parallel top & bottom chord member. A roof truss with sloping top chord & a horizontal bottom chord, for instance would experience the highest axial forces at the members closest to the supports. Best regards, Temo Gracia, P.E.
Hi Thomas, different countries show bending moment diagrams in different ways. In our university we always draw the BMD on the tension face of a member (this is the same approach that the IStructE takes too). It is best to be consistent but in the end the choice is rather arbitrary. Mike
Hi Aman, calling a bending moment -ve or +ve is really an arbitrary thing. By looking at the free body diagram to the right of D you have correctly found the value of the bending moment to be 60kNm. But why is your calc -ve when my calc is +ve? Because, when we cut through a beam we expose the internal forces in the beam and looking at the left hand side of the cut, there is a couple formed by the compressive forces in the top and the tensile forces in the bottom. Let's say that this couple acts in a clockwise manner. When we look at the right side of the beam the compressive and tension forces are acting the opposite way and so the couple is acting in an anti-clockwise manner. Hence the difference in signs. I hope this helps.
Aman Deep Hi Aman, you might not be getting it, but your calculation is giving you the correct value of the bending moment and the correct sign. That's a good start. You just have to think about how the internal forces in the beam are acting. Best of luck.
Hi Jitu M, That is a good question which I won't answer fully here, you could ask your structures lecturer though. It is the case that the loading of a beam is directly related to the shear force diagram. Additionally, the rate of change of the shear force along a beam is directly related to the bending moment in the beam. Calculus can be used to explain these relationships and particularly it can be shown that where the bending moment diagram has maxima and minima, then at those points, there must be zero shear. I suggest Alan Jennings' book for a brief introduction to this. Sorry to be so brief but I hope that this helps.
Shear force is the derivative of the Moment (the Moment is the antiderivative of shear force). Therefore, when the shear force is zero, you get the moment max. The Shear force is calculated from the vertival forces perpendicular to the beam. The Moment is calculated from the same vertical forces multiplied by a distance x. So, if you have a calculator with graph you could make a program in which you would enter 2 points to trace the graph of the Shear force function, and then you would calculate the integral to figure out the Moment max.
dude draws like a precision robot. good job!
Yeah holy shit ,how about that first line he drew
Literally no words to describe how simple and easy you made us understand…. Simply amazing and wonderful… hope to see more in near future… keep it up…
Thanks very much for the video! Love the way you teach. Very clear and concise. can you do a vid that covers a UDL with a supporting wall to obtain the size of the RSJ?
Cheers mate, really helped a lot. But correct me if im wrong, this is the same as first calculating the shearing forces, drawing the SFD and then getting the BMD from that too right?
I may be missing something here, but isn't a clockwise direction considered negative when considering a moment?
Hi Alissa, in analysis, we follow some arbitrary conventions to help to keep us sane. In the UK structural engineers draw bending moments on the tension face of beams, whereas mechanical engineers draw them on the compression face. You could consider clockwise moments to be negative or positive. The most important thing you can do when analysing moments is to be consistent and to clearly understand the size of any moments and to understand whether a beam is hogging or sagging. On this basis, I can’t say that you are right or that I am right, I hope that this helps, Mike
excellent!!I like ur approach and explanation, will u please add more tutorials like slabs, beams, and how to calculate no of bars.thns
I watched this in October of 2019. Very helpful
Excellent tutorial! Very clear. Thanks for your time.
Nice job
ruclips.net/video/fRyUf-GY754/видео.html.
Great explanation I understand now finally 😂😂😂😂
very clear explanation and step by step teaching :) Thank you very much!!
Thank you very much for this, only wish my uni lecturers explained this the way you have, top work, cheers ; )
Thank you brother, your teaching way is good understanding.
You are a legend! Just saved my uni coursework!
Thank so very much for this precised explanation.
thank you, this is really helpful
(10-JAN-2020) Excellent!!I like Ur approach and explanation. GO ON!!!
ruclips.net/video/fRyUf-GY754/видео.html.
Awesome tuts Mike, congrats.
Thank you, best and easiest explanation out there
I really appreciate, you making this videos. this has helped me a lot. thank you
Thank you for making it easy to understand.
Gigi Machuca tk u sir
You draw like a boss!
This video is really helpful to me. Thank you so much.
Great video, thanks.
ruclips.net/video/fRyUf-GY754/видео.html.
It so much useful for me to understand.... Thank u....☺
understand this much better now, thank you very much :)
Thanks
Good explanation.
This video is really helpful to me thank you sir
Great explanation! Thanks
Helped a lot.
What happens when load comes in between UDL
kudos for the explanation.
you made it easy sir..thanks alot.
Thanks again! Great video
I have always been told that a Clockwise moment is negative and an Anti-Clockwise moment is positive?
Hi Ryan Mallin, thanks for your comment and I am not surprised that this is the case, as the decision to call clockwise moments positive or negative is wholly arbitrary. I can only tell you the way that we do things in our university in the North of England. The key thing is that you are consistent and then when you draw the bending moment diagram you plot the bending moments either always on the tension face of elements (or, if you are not attending our university perhaps) on the compression face of elements. I hope that this explains the inconsistency a little, Mike
Thank you , very neat .
thanks very much. helped alot
excellent!!I like ur approach and explanation !!
The way i see it.. the longer the distance from point A the higer the number.. does that mean the higer the load...
Im trying to calculate the max load ot safe load on a Y truss that im usung to suspend ligting and audio equipment.... im usin I beams from global truss...about 6.5m long each seccion..
Hi ladjkoaz, Thanks for your comment. Generally, for a simply supported beam, the bending moments are greatest around the centre of the span. If I understand you correctly, you are designing a simply supported truss - this would behave, in some ways, similarly to a simply supported beam. As the bending moments are greatest around mid-span, the axial forces in the members of the truss will be greatest here as well. Good luck with your analysis and design
+Mike Bather
Greetings Mike:
The maximum bending moment for a truss would indeed be located at mid-span given the same loading condition as above, however, the axial forces of the truss members would not necessarily occur at mid-span unless you are talking about a truss with a parallel top & bottom chord member. A roof truss with sloping top chord & a horizontal bottom chord, for instance would experience the highest axial forces at the members closest to the supports.
Best regards, Temo Gracia, P.E.
well expalined, thanks
Greaatt explaination!!
Is this parabola supposed to be the other way up??
Hi Thomas, different countries show bending moment diagrams in different ways. In our university we always draw the BMD on the tension face of a member (this is the same approach that the IStructE takes too). It is best to be consistent but in the end the choice is rather arbitrary. Mike
nice work so useful
Thanks
If we take the right side of point D . The BM is coming out to be -60
Explain?
Hi Aman, calling a bending moment -ve or +ve is really an arbitrary thing. By looking at the free body diagram to the right of D you have correctly found the value of the bending moment to be 60kNm. But why is your calc -ve when my calc is +ve? Because, when we cut through a beam we expose the internal forces in the beam and looking at the left hand side of the cut, there is a couple formed by the compressive forces in the top and the tensile forces in the bottom. Let's say that this couple acts in a clockwise manner. When we look at the right side of the beam the compressive and tension forces are acting the opposite way and so the couple is acting in an anti-clockwise manner. Hence the difference in signs. I hope this helps.
Not getting it
Aman Deep Hi Aman, you might not be getting it, but your calculation is giving you the correct value of the bending moment and the correct sign. That's a good start. You just have to think about how the internal forces in the beam are acting. Best of luck.
Thanks!
thanks so much
thank you!!!
thx bro u are d best ^_^
You haven’t got a shear force diagram for this beam
thanks brother
why zero shear force means maximum bending moment????
Hi Jitu M, That is a good question which I won't answer fully here, you could ask your structures lecturer though. It is the case that the loading of a beam is directly related to the shear force diagram. Additionally, the rate of change of the shear force along a beam is directly related to the bending moment in the beam. Calculus can be used to explain these relationships and particularly it can be shown that where the bending moment diagram has maxima and minima, then at those points, there must be zero shear. I suggest Alan Jennings' book for a brief introduction to this. Sorry to be so brief but I hope that this helps.
Thanks a lot sir
Shear force is the derivative of the Moment (the Moment is the antiderivative of shear force). Therefore, when the shear force is zero, you get the moment max. The Shear force is calculated from the vertival forces perpendicular to the beam. The Moment is calculated from the same vertical forces multiplied by a distance x. So, if you have a calculator with graph you could make a program in which you would enter 2 points to trace the graph of the Shear force function, and then you would calculate the integral to figure out the Moment max.
We are looking forward to us more plz
nice 1 :)
Thank you so much ofcourse not the Barak Obama way... I mean thank you Sir for real
Mc will be 80 u wrote 60
It’s off the camera he wrote Mc = 80kN from the 160-80