Followed the equations from the page below. Thanks for greate explanations. Basically, I wrote up this flow, but slightly changed something since it is wrong sometimes. https://qiita.com/Altaka4128/items/41101c96729b68d7c96f The formulation of the finite element method for stress analysis The FEM formulation is as follows. Displacement and Stiffness Matrix Relation of Stress and Strain By the way, … Continue reading Finite Element Method for Stress Analysis