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12-Amethyst
Dec 1, 2023 3:41 PM UTC
Solved

FEA - global stiffness matrix

Good day. I was wondering if anyone can introduce a good tutorial and help me on how I can compile the global stiffness of this example problem in mathcad prime. I am currently studying FEA Method and still do not know how to properly mesh 2d into a single matrix. I hope anyone can help me program it. Thank you.

terryhendicott
21-Topaz II
Dec 1, 2023 11:52 PM UTC

Hi Teddy

Errata for reference https://sharif.edu/~ghaemian/Finite-Element_files/File/chapter3.pdf that gives erroneous results.

Make three small changes and it works

1> Add minus to k2 in column 0

2> Add minus to k5 in column 0

3> For k3 first term divisor is S not 3.

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Capture2.JPG

Capture3.JPG

Cheers

Terry

 

5 replies

15-Moonstone
Dec 1, 2023 5:22 PM UTC

Perhas this link will help.

https://www.youtube.com/watch?v=D6Qdy929K0Q 

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16-Pearl
Dec 1, 2023 6:27 PM UTC

If you happen to have access to Mathcad v15 and you have the mechanical engineering e-books, there is a book about FEA - "Finite Elements Beginnings". All the examples you will need are contained in that book.

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terryhendicott
21-Topaz II
Dec 1, 2023 8:00 PM UTC

Here is one way

But it is not giving the correct answer so looking at it

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terryhendicott
21-Topaz II
Dec 1, 2023 9:22 PM UTC

Hi Teddy,

Happy it is now working with a third attempt at elemental stiffness matrix.

Capture.JPG

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terryhendicott
21-Topaz II
Dec 1, 2023 11:52 PM UTC

Hi Teddy

Errata for reference https://sharif.edu/~ghaemian/Finite-Element_files/File/chapter3.pdf that gives erroneous results.

Make three small changes and it works

1> Add minus to k2 in column 0

2> Add minus to k5 in column 0

3> For k3 first term divisor is S not 3.

Capture.JPG

 

Capture2.JPG

Capture3.JPG

Cheers

Terry

 

Translate