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SPRstructur15-Moonstone
15-Moonstone
February 3, 2022
Solved

11.9.2 Transformation of the nodal coordinates of the space frame element

  • February 3, 2022
  • 2 replies
  • 15466 views

Dear All 
Please help for calculating  Transformation of the nodal coordinates of the space
frame element, I stuck here both theory and Mathcad Prime.

I attached file of Mathcad prime sheet and lesson and example.

Best regards
SPRStructur

 

Best answer by terryhendicott

Hi,

Have eliminated the error.

The case where the member aligns with the z axis needs to be taken into account.

Have added an if statement that defines this.

Cheers

Terry

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2 replies

T
21-Topaz II
terryhendicott21-Topaz II
21-Topaz II
February 4, 2022

Hi,

Here is how a commercial piece of software defines P on the y(2) axis.

In the graphic axis 3,2,1 is the same as your local coordinates x,y,z.

x(3) local is along the member.

y(2) local is defined as Y global for beams parallel to Z global axis.

y(2) is defined by vector product of Z and 3 if not parallel to Z global

z(1) completes the orthogonal set.

Capture.JPG

Define y(2) as above and you can set P for your example.

 

Cheers

Terry

    T
    21-Topaz II
    terryhendicott21-Topaz II
    21-Topaz II
    February 4, 2022

    Hi,

    Took time to show how to calculate P.

    The case for element on z axis is trivial so not covered.

    Cheers

    Terry

    Capture2.JPG

      S
      SPRstructur15-MoonstoneAuthor
      15-Moonstone
      February 4, 2022

      Hello @terryhendicott 
      I got error when I apply my example

       

       

      T
      21-Topaz II
      terryhendicott21-Topaz IIAnswer
      21-Topaz II
      February 4, 2022

      Hi,

      Have eliminated the error.

      The case where the member aligns with the z axis needs to be taken into account.

      Have added an if statement that defines this.

      Cheers

      Terry

      Capture.JPG

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