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Static Analysis of C-Clamp

Question asked by Jignesh M. Patel on Mar 1, 2015
Latest reply on Mar 5, 2015 by Jared Conway

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Hello Friends,

I am trying to do static analysis of C-Clamp Assembly for 300 N load (vertical direction) on Jaw and keeping bottom face of clamp as fixed.

I do not have clear idea about Connections & components sets..analysis fails during meshing of "cap screw2" & screw rod1". Do not know why?

May be i forgot something about contacts or connections or may be due to screw..i don`t know..please help me to find von-misses stress for this assembly.

I can perform analysis of individual components except screw rod1.

material for C Frame is FG260 (= Ductile iron)

Rest of parts of AISI 1020

Message was edited by: Jignesh M Patel

Mike Pogue Mar 1, 2015 11:42 PM

Correct Answer

The von Mises stress plot attached looks correct. It also looks like you have a safety factor of 112.

The boundary conditions you propose make sense, especially because the max stress is far from the fixed point. You simply don't need FEA to calculate the stress in the screw. It's F/A. Calculate it with a pencil. You have three conditions to check, shear in the threads (F/shear area, make sure you use shear strength as allowable), compressive stress in the screw (F/tensile stress area), and bearing between the screw and the end piece (F/projected area, you should be willing to let this yield a little--it's not going anywhere)

See the reply in context

Attachments

Rod Probe.JPG80.9 KB
Assem Probe.JPG59.4 KB
Assemb FEA.JPG118.1 KB
Von misses with yield strength.JPG66.8 KB
Analysis of C Clamp.rar5.8 MB
Assembly Loading.JPG86.5 KB
IMG-20150301-WA0012.jpg230.7 KB
IMG-20150301-WA0011.jpg196.0 KB

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J. Mather Mar 1, 2015 7:47 AM

Can you attach folder without using rar compression?

I don't think you would need many of those parts in the analysis (perhaps only the frame).

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Jignesh M. Patel @ J. Mather on Mar 1, 2015 10:49 PM

Sir,

I already did FEA of C frame and it is success.. no issue with that.

Problem encounters while doing FEA of Screw Rod due to threads on it.

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Seckin Uslu Mar 1, 2015 2:55 PM

The screw mesh generate many elements . You should suppress the cut sweep feature on screw part.

Like J. Mather said you dont need many of those parts.

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Jignesh M. Patel @ Seckin Uslu on Mar 1, 2015 10:56 PM

yes dear your are right.

But after suppressing that feature (cut sweep) and considering plain rod and and find stress in rod as attached...but i am not sure this is right.

Second thing i have consider cylinder body (shank) as fix end condition and applied load of 300 N at bottom end and got results shown in attachment.

I also omitted handle and collar and pin from analysis..but due to screw rod and improper contact condition i am not able to carry out analysis in assembly mode.

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Mike Pogue @ Jignesh M. Patel on Mar 1, 2015 11:42 PM

The von Mises stress plot attached looks correct. It also looks like you have a safety factor of 112.

Actions

Jignesh M. Patel @ Mike Pogue on Mar 2, 2015 12:57 AM

Hi Mike your are right but i want to prove that using simulation..that is it.

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Mike Pogue Mar 1, 2015 5:14 PM

+1 for both comments.

Analyze the load on the frame using FEA as a single part. Ignore concentrations where the loads are applied

Analyze the compressive load in the screw by looking up the proof load, or the proof stress and the stress area.

Analyze the stress on the threads by looking up the thread shear area.

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Jignesh M. Patel Mar 3, 2015 1:26 AM

Friends please share your views on results i have achieved in assembly mode is it OK ?

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Jared Conway @ Jignesh M. Patel on Mar 3, 2015 8:46 PM

what do you mean are they ok?

and what results specifically are you referencing?

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Jignesh M. Patel @ Jared Conway on Mar 3, 2015 10:29 PM

I mean from load, fixture and importantly connection type between components that i have applied. results are consistent with my hand calculations.

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Jared Conway @ Jignesh M. Patel on Mar 5, 2015 2:32 AM

only you can tell us that!

but if they line up with your hand calculations, that is a good sign

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11 Replies

J. Mather Mar 1, 2015 7:47 AM
Mark Correct
Correct Answer
Can you attach folder without using rar compression?

I don't think you would need many of those parts in the analysis (perhaps only the frame).
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- Jignesh M. Patel @ J. Mather on Mar 1, 2015 10:49 PM
  Mark Correct
  Correct Answer
  Sir,
  I already did FEA of C frame and it is success.. no issue with that.
  Problem encounters while doing FEA of Screw Rod due to threads on it.
  Like • Show 0 Likes0
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Seckin Uslu Mar 1, 2015 2:55 PM
Mark Correct
Correct Answer
The screw mesh generate many elements . You should suppress the cut sweep feature on screw part.

Like J. Mather said you dont need many of those parts.
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- Jignesh M. Patel @ Seckin Uslu on Mar 1, 2015 10:56 PM
  Mark Correct
  Correct Answer
  yes dear your are right.
  
  But after suppressing that feature (cut sweep) and considering plain rod and and find stress in rod as attached...but i am not sure this is right.
  
  Second thing i have consider cylinder body (shank) as fix end condition and applied load of 300 N at bottom end and got results shown in attachment.
  I also omitted handle and collar and pin from analysis..but due to screw rod and improper contact condition i am not able to carry out analysis in assembly mode.
  Like • Show 0 Likes0
  Actions
  - Mike Pogue @ Jignesh M. Patel on Mar 1, 2015 11:42 PM
    Unmark Correct
    Correct Answer
    The von Mises stress plot attached looks correct. It also looks like you have a safety factor of 112.
    
    The boundary conditions you propose make sense, especially because the max stress is far from the fixed point. You simply don't need FEA to calculate the stress in the screw. It's F/A. Calculate it with a pencil. You have three conditions to check, shear in the threads (F/shear area, make sure you use shear strength as allowable), compressive stress in the screw (F/tensile stress area), and bearing between the screw and the end piece (F/projected area, you should be willing to let this yield a little--it's not going anywhere)
    Like • Show 1 Like1
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    - Jignesh M. Patel @ Mike Pogue on Mar 2, 2015 12:57 AM
      Mark Correct
      Correct Answer
      Hi Mike your are right but i want to prove that using simulation..that is it.
      Like • Show 0 Likes0
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Mike Pogue Mar 1, 2015 5:14 PM
Mark Correct
Correct Answer
+1 for both comments.
Analyze the load on the frame using FEA as a single part. Ignore concentrations where the loads are applied
Analyze the compressive load in the screw by looking up the proof load, or the proof stress and the stress area.
Analyze the stress on the threads by looking up the thread shear area.
Like • Show 1 Like1
Actions
Jignesh M. Patel Mar 3, 2015 1:26 AM
Mark Correct
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Friends please share your views on results i have achieved in assembly mode is it OK ?
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- Jared Conway @ Jignesh M. Patel on Mar 3, 2015 8:46 PM
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  what do you mean are they ok?
  
  and what results specifically are you referencing?
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  - Jignesh M. Patel @ Jared Conway on Mar 3, 2015 10:29 PM
    Mark Correct
    Correct Answer
    I mean from load, fixture and importantly connection type between components that i have applied. results are consistent with my hand calculations.
    Like • Show 0 Likes0
    Actions
    - Jared Conway @ Jignesh M. Patel on Mar 5, 2015 2:32 AM
      Mark Correct
      Correct Answer
      only you can tell us that!
      but if they line up with your hand calculations, that is a good sign
      Like • Show 0 Likes0
      Actions

Static Analysis of C-Clamp

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