Another good example would be the simple 2x4 or 2x6 used as structural members in home building. Placed in the "flat" side up and down with most of the material in the center where it does the least good, the board is not that strong. Turn it 90 degrees so more of the material is toward the top and bottom, the board is much stronger. Take that to the next level where you have floor joists that are designed to bear lots of load. The dimension might be 1x8, and oriented vertically the boards are very strong with much more of the material towards the top and bottom. A lot of people may know this just from experience without knowing the science behind it.
Thanks for the video. It was confusing to hear you talk about an increased cross-sectional area in the I-Beam, as from the drawing, it looks like the cross-sectional area is smaller. Isn't the benefit of using an I-Beam more related to reduction in weight / required materials? I think it would have been useful to draw scale cross-sections of the two beams, so we can clearly see increased area.
Yeah, that was kindof confusing. A beam that is a block (ie rectangular prism) that is as wide as the top/bottom of an I-beam will be better than the I-beam in terms of sturdiness (i think people may be misled to think differently from this video). However, when limited in materials/weight restrictions, it makes sense to put most of the material where the compression and tension forces are greatest, and then connect the two with a thinner middle section. This placement of material is the most effective.
Why do shipping containers have ridges? I imagine it's mostly to contribute to the structural integrity (though, kinda like why a golf ball has pockets, it can also contribute to aerodynamics?).
Hi sir, lastly i 've been watching your physics videos by the bigger Playlist. On "physics mechanics 4" this video is not on it, and also the videos between 3-7 from stress and strain. Besides that, this is a very good Playlist. Keep on going
...Q: ..... Is a structural "I- beam" STRONGER when the single/central part is the vertical web between the top and bottom surfaces, or, if it is rotated 90 degrees, and sits as an "H-beam", with 2 vertical webs, separated by the common single/central portion of the beam?! Is it stronger when used as an "I", or an "H" ?!....(assuming that the beam has the same dimension across either face).
hello sir ,if the beam has max shear force at a point what will appen ?? also if the beam has maximum bending moment what will happen?? iam terribly confused with both these terms they confuse a lot...why we need to calculate shear force disstrbution what's the purpose???
pradeep, When a beam is subjected to a force greater than it can withstand, failure will occur. The type of failure will depend on how the force is applied. A shear force will cut or sever the beam. I am not familiar with the term "bending moment". That may be a translation problem.
bending moment is the integral of shear force ....when we have maximum shear we have max bending that is not a problem if the bending is still in the safe limit .. so the shear or bending can be maximum at a point but that it did not reach its yield point or the failure point . or what ever you design the beam for ...!
+Michel van Biezen From top layer there is a sudden drop in cross sectional area wouldnt it be better if we had a linear decrease in area till central axis and then a linear increase till bottom portion?
+Michel van Biezen How can the cross-sectional area become larger if you remove big parts of the original beam? To me it looks like the cross-sectional area is much smaller on the I-beam.
We prefer not to endorse texts, but there are actually a lot of very good texts out there. It becomes more of a personal preference as each one of them will contain good presentation material.
How can the cross-sectional area become larger if you remove big parts of the original beam? To me it looks like the cross-sectional area is much smaller on the I-beam. - @Laurelindo i have the same question.
+Chris Wass You would never make a beam with the same dimensions if it was the solid. By making an I beam you can make the top and bottom of the beam larger, which is the only part of the beam that matters. (That is why you have such a large top and bottom strip).
@@MichelvanBiezen , thank you for the info! I was considering I-beams initially, but my plans are for a geodesic dome, in which most struts are in various angles, and while the I-beams can be oriented correctly it would make the connector-hubs much more complicated.
Your teaching is beyond excellent, thank you so much for making these videos Michel!
I never new it was the top and bottom section that make it strong. Makes a lot of sense, thanks.
Sir you are amazing. You literally are saving my ass I have an exam tomorrow. I wish every teacher was like you. Cheers from Dubai.
Another good example would be the simple 2x4 or 2x6 used as structural members in home building. Placed in the "flat" side up and down with most of the material in the center where it does the least good, the board is not that strong. Turn it 90 degrees so more of the material is toward the top and bottom, the board is much stronger. Take that to the next level where you have floor joists that are designed to bear lots of load. The dimension might be 1x8, and oriented vertically the boards are very strong with much more of the material towards the top and bottom.
A lot of people may know this just from experience without knowing the science behind it.
Thanks for the video.
It was confusing to hear you talk about an increased cross-sectional area in the I-Beam, as from the drawing, it looks like the cross-sectional area is smaller. Isn't the benefit of using an I-Beam more related to reduction in weight / required materials?
I think it would have been useful to draw scale cross-sections of the two beams, so we can clearly see increased area.
Yeah, that was kindof confusing. A beam that is a block (ie rectangular prism) that is as wide as the top/bottom of an I-beam will be better than the I-beam in terms of sturdiness (i think people may be misled to think differently from this video). However, when limited in materials/weight restrictions, it makes sense to put most of the material where the compression and tension forces are greatest, and then connect the two with a thinner middle section. This placement of material is the most effective.
Why do shipping containers have ridges? I imagine it's mostly to contribute to the structural integrity (though, kinda like why a golf ball has pockets, it can also contribute to aerodynamics?).
There are many ways to strengthen the construction of objects such as containers. Adding I beams is one of them.
it has also relation with I beam's large moment of inertia
thanks for simplifying things for me
Hi sir, lastly i 've been watching your physics videos by the bigger Playlist. On "physics mechanics 4" this video is not on it, and also the videos between 3-7 from stress and strain.
Besides that, this is a very good Playlist. Keep on going
...Q: ..... Is a structural "I- beam" STRONGER when the single/central part is the vertical web between the top and bottom surfaces, or, if it is rotated 90 degrees, and sits as an "H-beam", with 2 vertical webs, separated by the common single/central portion of the beam?! Is it stronger when used as an "I", or an "H" ?!....(assuming that the beam has the same dimension across either face).
A beam is stronger when used as an I, and the strength increases as I becomes taller.
Michel van Biezen say the I-beam is laying with the web horizontally instead of vertical. Why is that not as strong?
so a wider and thicker section is preferable to a taller section,
Many Thanks
И все-таки! Ферма из профильной трубы или двутавр?
sir,how shear stress will propagate in the beam means how graph of shear stress will be...
hello sir ,if the beam has max shear force at a point what will appen ?? also if the beam has maximum bending moment what will happen?? iam terribly confused with both these terms they confuse a lot...why we need to calculate shear force disstrbution what's the purpose???
pradeep,
When a beam is subjected to a force greater than it can withstand, failure will occur. The type of failure will depend on how the force is applied. A shear force will cut or sever the beam.
I am not familiar with the term "bending moment". That may be a translation problem.
thank u sir..
bending moment is the integral of shear force ....when we have maximum shear we have max bending that is not a problem if the bending is still in the safe limit .. so the shear or bending can be maximum at a point but that it did not reach its yield point or the failure point . or what ever you design the beam for ...!
Any chance you can do one on a castellated beam? There are none on here
why do we use the 'I' section as the cross sectional area? why not we use the top surface area because we applied the force from the top.
+Farah Afiqah Think about it this way. What if we removed all but the top layer. How strong would it be? What gives the I beam the strength?
+Michel van Biezen oh i get it. thank you sir
+Michel van Biezen From top layer there is a sudden drop in cross sectional area wouldnt it be better if we had a linear decrease in area till central axis and then a linear increase till bottom portion?
+Michel van Biezen
How can the cross-sectional area become larger if you remove big parts of the original beam?
To me it looks like the cross-sectional area is much smaller on the I-beam.
What book would you recommend for introductory physics books
We prefer not to endorse texts, but there are actually a lot of very good texts out there. It becomes more of a personal preference as each one of them will contain good presentation material.
How can the cross-sectional area become larger if you remove big parts of the original beam? To me it looks like the cross-sectional area is much smaller on the I-beam. - @Laurelindo
i have the same question.
+Chris Wass
You would never make a beam with the same dimensions if it was the solid. By making an I beam you can make the top and bottom of the beam larger, which is the only part of the beam that matters. (That is why you have such a large top and bottom strip).
Physics is phun! I'm a highskool dropout engineering student and quantum mechanic of sorts. Lol
1st year Theory of Structure in Civil and Structural Engineering.
How does steel pipe compare to an I-Beam?
A steel pipe is not nearly as strong.
@@MichelvanBiezen , thank you for the info!
I was considering I-beams initially, but my plans are for a geodesic dome, in which most struts are in various angles, and while the I-beams can be oriented correctly it would make the connector-hubs much more complicated.
Circular cross-section beams can be used if the forces are along the length of the beams. I-beams are used for perpendicular loads.
Still why they have to make it hollow and not a cube?
It would require a lot more material (cost) and it would be too heavy.
Belly of the beam
HAHHAHA thank you, good sir!
nyz