. .
Page 2 of 2 FirstFirst 12
  1. #11
    You may be able to save a bit of time analyzing the components using this:

    https://skyciv.com/free-moment-of-inertia-calculator/

    It does shapes such as I beam, T beam and angle as well as tubes.

  2. #12
    Quote Originally Posted by Voicecoil View Post
    You may be able to save a bit of time analyzing the components using this:

    https://skyciv.com/free-moment-of-inertia-calculator/

    It does shapes such as I beam, T beam and angle as well as tubes.

    That's quite a handy calculator, so it might be all you need.


    But if you want to know what it is doing, there are quite a few steps involved (which is why you are better making a spreadsheet if you want to do lots of them). I've shown a worked example which uses 2 rectangles in a T shape. You can make any shape using more rectangles but need to include more terms in each equation associated with each new rectangle.

    The T shape is worked through in 7 steps:


    Click image for larger version. 

Name:	example01.jpg 
Views:	203 
Size:	106.8 KB 
ID:	26487
    Click image for larger version. 

Name:	example02.jpg 
Views:	203 
Size:	91.6 KB 
ID:	26488

    Click image for larger version. 

Name:	example03.jpg 
Views:	191 
Size:	147.2 KB 
ID:	26489

    Click image for larger version. 

Name:	example04.jpg 
Views:	180 
Size:	56.8 KB 
ID:	26490

    Hope this helps.
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  3. #13
    dn7's Avatar
    Lives in CAMPBELL, United States. Last Activity: 02-09-2022 Has been a member for 1-2 years. Has a total post count of 1.
    Quote Originally Posted by routercnc View Post
    New features in version 7 are:
    • Stiffness approximations of commercial ali profiles (e.g. Hepco)*
    • I value calculations for arbitrary shapes, not just RHS, round etc. This is a standalone calc and gives vertical bending deflection only.
    • Gantry top bending in the X direction (previously ignored)
    • Visual tool deflection error graph vs requirement
    Usual disclaimers apply.
    Hi routercnc,

    the stiffness calculator looks incomplete. Is it still cooking on the back burner, or did you abandon it completely, lost interest? If so, it'd be sad because it's hard to explain how important I feel this tool is.

    Regards,
    DN

  4. #14
    Quote Originally Posted by dn7 View Post
    Hi routercnc,

    the stiffness calculator looks incomplete. Is it still cooking on the back burner, or did you abandon it completely, lost interest? If so, it'd be sad because it's hard to explain how important I feel this tool is.

    Regards,
    DN
    I wrote this along time ago when I was designing my first machine to explore the importance of design choices. It got to a point where it worked well enough and would allow most users to gain some design principles for their own machine. I stopped there and have no plans to go further. For the next level of analysis with more complex shapes you need to step up to FEA but this works in a different way and needs commercially coded software to run. My advice would be to have a play and come away with some principles, such as material needs to be far away from the neutral axis to resist bending and torsion. But in the end the design still needs to be practical and buildable.
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

Page 2 of 2 FirstFirst 12

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. stiffness measurements cnc mk3
    By routercnc in forum Gantry/Router Machines & Building
    Replies: 27
    Last Post: 27-04-2014, 09:00 PM
  2. Simple O-ring calculator.
    By jcb121 in forum General Computing
    Replies: 4
    Last Post: 26-07-2013, 09:00 PM
  3. PCB Track Width Calculator
    By irving2008 in forum General Electronics
    Replies: 0
    Last Post: 10-05-2013, 02:34 PM
  4. Resistor Calculator
    By Lee Roberts in forum General Electronics
    Replies: 2
    Last Post: 17-04-2012, 05:22 AM
  5. Loading Calculator for Z axis
    By Ross77 in forum Linear & Rotary Motion
    Replies: 7
    Last Post: 28-07-2010, 09:57 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •