Can anyone tell me where can i get step by step guide for formulation of K matrix of an 8-noded element with 3(along orthogonal axes direction) DoF in each node. The element material may be elastically different along three axes
This and a lot of other useful formulations are given in the book "Finite Element Analysis using Matlab". It is by a Korean author, I don't recollect the name. It is a very good reference book. You can also refer "The Finite Element Method in Engineering" by S.Rao. It has some formulations too.