Eng-Tips is the largest forum for Engineering Professionals on the Internet.

Members share and learn making Eng-Tips Forums the best source of engineering information on the Internet!

Register Log in
  • Congratulations dmapguru on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

BOLTED JOINT FREE BODY DIAGRAM 2

Status
Not open for further replies.
eli28

eli28

Aerospace
Joined
Oct 20, 2019
Messages
109
Location
IL
Hello,

I would like to make sure I frew the bolted joint Free Body Diagram correctly?
The motivation is identifying which force act directly on the joint surfaces for friction calculations and local normal stresses.
FBD_hdlodq.jpg
 
Sort by date Sort by votes
How are your forces being applied? Here is my free[‑]body diagram of a screw, which does show an external force...

ScrewConnection_ujvzfv.png

On my drawing, I have labelled enough forces that I can intelligently discuss whether or not that screw will lift off. I ought to show a compressive force between the bracket and the fixed beam.

--
JHG
 
Upvote 0 Downvote
drawoh, that's a poor free body diagram. Should not show internal forces.

Ted
 
Upvote 0 Downvote
Try what where? The link doesn't link to a file.
 
Upvote 0 Downvote

It's gone... I think this was the file I downloaded... I don't know what happened... it was just there.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
 https://files.engineering.com/getfile.aspx?folder=dae6825e-ded3-4450-a317-118d40813948&file=Bolted_Joints_design_n_behavior.pdf
Upvote 0 Downvote
dik

That was an interesting link thanks

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
 
Upvote 0 Downvote
ok, I'll ask ... why are you interested in friction forces ? the variation in CoF will make a mockery of any analysis.

another day in paradise, or is paradise one day closer ?
 
Upvote 0 Downvote
friction... bigtime.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
Upvote 0 Downvote
@dik ... ??

another day in paradise, or is paradise one day closer ?
 
Upvote 0 Downvote
The tension in the bolt is hugely dependent on the friction... that's why calibrated torque wrenches are contraindicated as a means of checking tensioning.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
Upvote 0 Downvote
yes, friction of the nut on the threads ... I thought the OP was looking for friction on the clamped plates.

another day in paradise, or is paradise one day closer ?
 
Upvote 0 Downvote
it's all part of the turkey shoot... I have a couple of papers that address all components... I'll see if I can dig them up.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
Upvote 0 Downvote
Hey dik
Thanks for the book, I reviewed it but couldn't find an entire free body diagram in it for comparing to mine.
At least it's a good book, so I keep it 🙂
 
Upvote 0 Downvote
Maybe mechanical... but, your FBD is not common...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
Upvote 0 Downvote
dik - I didn't understand...?
 
Upvote 0 Downvote
hydtools said:
drawoh, that's a poor free body diagram. Should not show internal forces.
Click to expand...

The internal forces are what I am interested in.

--
JHG
 
Upvote 0 Downvote
I think it's a bit pedantic to say the diagram posted is not a FBD. It is in balance, it shows the loadpaths, it shows the detail that the poster wants to discern; that's good enough for me.

another day in paradise, or is paradise one day closer ?
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

grunt58
  • Locked
  • Question Question
Free body diagram and cylinder force help
2
Replies
26
Views
2K
hydtools
hydtools
pmbov
  • Locked
  • Question Question
Free Body Diagram - Ball and Socket (both ends)
Replies
3
Views
948
drawoh
drawoh
IronLotus
  • Locked
  • Question Question
Bolted Joint Design & Preload; Varying Number of Identical Bolts
Replies
3
Views
761
IronLotus
IronLotus
elinah34
  • Locked
  • Question Question
Failure of a bonded joint that has a thread
2
Replies
25
Views
2K
Compositepro
Compositepro
EngTipsAccount1234
  • Locked
  • Question Question
Does a bolt in a threaded hole have a preload or clamping force? If not, what is keeping the joint together.
Replies
7
Views
3K
mfgenggear
mfgenggear

Part and Inventory Search

Sponsor

Back
Top