Beam deflection

Steve_willits · July 2021

Hi,

Does Onshape have beam deflection analysis? I am looking for something simple like calculating the maximum deflection of a steel bar, supported at both ends, with load in the middle.

Thanks,

Steve

GregBrown · July 2021

There's nothing built in, and using a full featured simulation code (FEA) would be way overkill if (as you describe) you are only looking for simply supported/mid point loaded bars. The formula for calculating the max deflection (max d = FL^3/48EI) is simple enough, along with I (I = bh^3/12 for a rectangular solid section; other sections easily found online) - so it would be easy to set up a couple of variables as inputs (F, L, E, I, b, h) and spit out a result.

Alternatively you could built a CustomFeature that takes a selected edge, various inputs and displays a max deflection. It would be a great learning exercise as this would be a very simple one. I had a quick bash at it:

Image: https://us.v-cdn.net/5022071/uploads/editor/wd/04ml9c00mkax.png

Edited to add my public doc:
https://cad.onshape.com/documents/0bb2acf917e0c2f890197ca7/w/34d26b4ab5b6c3e4ceeb688c/e/f94fb66fd110abfbfb51de27

I also included a part studio that does it simply with variables. Use the variable table

Image: https://us.v-cdn.net/5022071/uploads/editor/pd/fqp25mti1nqq.png

for the best way to view

TimRice · July 2021

I do have this super old custom feature that used the beam equations to calculate beam deflections:
https://cad.onshape.com/documents/21fa541ca92d7d95aea12b6d/v/8b31dd78d7faf7097352ce7b/e/a7050d236d39980ebd6a0bc3

GregBrown · July 2021

There's nothing built in, and using a full featured simulation code (FEA) would be way overkill if (as you describe) you are only looking for simply supported/mid point loaded bars. The formula for calculating the max deflection (max d = FL^3/48EI) is simple enough, along with I (I = bh^3/12 for a rectangular solid section; other sections easily found online) - so it would be easy to set up a couple of variables as inputs (F, L, E, I, b, h) and spit out a result.

Alternatively you could built a CustomFeature that takes a selected edge, various inputs and displays a max deflection. It would be a great learning exercise as this would be a very simple one. I had a quick bash at it:

Edited to add my public doc:
https://cad.onshape.com/documents/0bb2acf917e0c2f890197ca7/w/34d26b4ab5b6c3e4ceeb688c/e/f94fb66fd110abfbfb51de27

I also included a part studio that does it simply with variables. Use the variable table

for the best way to view

TimRice · July 2021

I do have this super old custom feature that used the beam equations to calculate beam deflections:
https://cad.onshape.com/documents/21fa541ca92d7d95aea12b6d/v/8b31dd78d7faf7097352ce7b/e/a7050d236d39980ebd6a0bc3

Jake_Delano · July 2021

Hi Steve, at the moment Onshape does not have simulation tools built into the product, but we announced in our Onshape Sneak Peek at Onshape Live 2021 that it would be coming out soon. For now I would suggest checking out the App Store to see some of our partner apps for simulation. For simple calculations I would suggest trying Onscale Solve which you can try for free.