I have gone through Beam Element analysis in several books on FEA. 80% of books have a particular Stiffness matrix, while a very small number of books have a matrix which is subtly different in sign.(adsbygoogle = window.adsbygoogle || []).push({});

http://www.flickr.com/photos/66943862@N06/7195680680/in/photostream/lightbox

Most books have the 2nd matrix in the photo above.

A couple of books have 1st one.

Likewise the loading matrix is also slightly different.

Corresponding to the first one, the loading matrix is F*L/12 [ 6 -L 6 L]^{T}

While the majority have F*L/12 [ 6 L 6 -L]^{T}

Which method is correct?

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# FEA: Stiffness Matrix for Beam Element

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