Axial Deformation - Force Method for Statically Indeterminate Member

[@rcutler9]

Wow this was explained so much better here than in my class. Thank you

[@structurefree]

any time you have more unknowns than equilib equations, there is a redundant force. the redundant can be any of the unknowns. this problems uses the principle of superposition to break up the structure into statically determinate "diagrams", the redundant diagram is the diagram where the reaction (that you selected as the redundant) is reintroduced as a load.

[@structurefree]

in civil engineering practice in the U.S. we use both the FPS and SI system, so I try to teach with both. But, it's just a matter of using appropriate conversion factors.

[@structurefree]

During the problem solving process, it is assumed that the Cx goes towards the right. The final result for Cx is negative, which means it is pointing to the left.

[@Ameralsna3ys]

thank you, thank you, thank you, thank you. you're the best.

[@henco363]

Thank you for the videos, helped a lot!

[@structurefree]

Thank you. your comment is super nice.

[@MoonRiver1324]

These videos are super helpful, thank you!

[@structurefree]

check out my mechanics of materials playlist, there are some examples of double integration method.

[@AbuTalha-db5ub]

These videos are great. Keep it up

[@jcjobin]

I am in engineering at Dalhousie University in Nova-Scotia, and I am taking mechanics of materials in first year ( required :/ ), and I do find these videos helpful, but we use different units, so I was wondering what the unit conversion was between kips and newtons. Thanks!

[@chrisjchu1291]

Hi Structuresfree your videos are lifesavers! I was wondering whether this method could still be used if instead of a point load, we had a linearly distributed axial load?

[@structurefree]

I'll try to do a video explaining. Without seeing the problem, I suspect that the WL/2EA came from an integration calculation.

[@Ezrays]

Thank you so much! Looking forward to your next videos! :D

[@rohitsrao]

Hi. Thanks a ton for your videos. They are helping me immensely. I did not understand why it is that you did not consider the horizontal reaction at A i.e Ax when drawing the loading and redundancy diagrams ?! Thanks

[@emilyf9950]

I found this video really helpful, I was just wondering why we ignore the Ax force on the redundant and loading diagram?

[@jacobraji2442]

There is a reaction force caused by Cx and the 12Kips but it is not the same Ax as in the original FBD. Since he left the wall in his drawings we can assume that these reaction forces are present.

[@nahiyanbakr6042]

Didn't understand the part where Nbc = 0? Can you guys make a free body force diagram to explain it? Thanks.

[@shylildude]

where's my "Structure Free Learning!" at the beginning?

[@structurefree]

shylildude ha, ha. it's an old video. Structure Fo-Rizzle.

[@WHY70122]

Sir, I'm confused. Shouldn't Csubx going towards left?

[@MrLazygrasshopper]

Bro, I'm puttin the word up. You da man... and, btw, i came across a question wherein a bar was hanging down from a fixed end and a load P acting on it. There's also the self weight of the bar acting. And deformation was asked. The answer was WL/2AE + PL/AE.... shouldn't it be WL/AE + PL/AE ? I mean, its just 2 loads... how can the formula change? thanks in advance

[@heinzrichung]

Thanks so much!!

[@jacobthomas6908]

Why didn't you include Ax in your first loading diagram? Thanks!!

[@justinfoto]

I might be wrong, but I think it's because he analyzes the right side of the cut so Ax wouldn't affect the FBD for the first loading diagram

[@zhenwang4539]

Maybe because Ax doesn't cause any deformation?

[@azadalmasov5849]

I think depending on loading and redundant diagram Ax is automatically and implicitly is either 50 kip or Cx to calculate deformation

[@structurefree]

oops, i just saw this comment. @TheBloodgigas is correct! Thank you!

[@yeohjunjie1277]

Sir, how do you determine which force is redundant? and what is the use of the redundant diagram?

[@MrPhenom1995]

why did you take the cut from right to left??Help appreciated

[@WhiteWingsnBlueSkys]

What if from A to ur 50K force the material was steel and then from the 50k force to C it was made out of brass (both had same area's though), what would you do then? so they have different E values for example if the steel had E = 200 000MPa and the brass had E=120 000MPa , how would you apply that in ur scenario? do you have an example of that kind of thing?

[@derarfasatla8657]

great job

[@teraniel11]

can u do a double integration method or moment area method?

[@husnainhyder6713]

Is there any simple way to understand all kinds of compatibilities of all kinds of structures

[@nahidtanbir284]

if two forces working in the beam suppose p=50kip & p=80kip , how can i solve that?

[@MilitaryConnect]

Why is the reaction at C pointing to the right. Shouldn't it be pointing towards the beam since that's the motion which is being restricted.

[@hxdistross8085]

Hey could you please refer a textbook for me to read through ?

[@nta3392]

thanks it helps

[@MegaLo0p]

do you have a video for Strain Energy? I hope you do haha

[@danielwilliams3378]

Why don't you include the Vertical reaction and Moment at C ? Why only Cx?

[@structurefree]

+Daniel Williams because the loading is only axial.

[@structurefree]

1 kip = 4.4482 kN

[@MrLazygrasshopper]

I'll put a video morro explaining the problem and some other interesting problems. Maybe you could do a video with all of em in it. Will PM the link to you and will comment here when done the same. Thanks in advance again ^_^

[@TheBloodgigas]

1 kip= nearly 4.5 Kilo newtons, (4448 N to be more precise) although the units in this video doesnt matter..

[@yuyu230894]

Why does δC0 + δC1 = 0? Why not δC0 - δC1 = 0?

[@structurefree]

yuyu230894 if you put the negative, it implies you already know the direction of the deformation. having the positive assumes, positive internal axial force and will be altered if the internal axial force is negative.

[@mohammedabuzour]

solving by Moment Distribution Method would be more helpful and simple isn't it!

[@MrLazygrasshopper]

Alright, I've PM the link to you. Check your inbox/PM. ty.