The problem with finite element analysis learning is that everybody is starting it from theory and after you are completely brainwashed, they start doing practical calculations. The theory for today FEM is so wide, that when you go for this super interesting practical case and you finally will apply your FE knowledge, suddenly ... it occurs you just do not remember theory... My approach here will be a little bit different. I will start explanation from a simple practical case, and I will be coming back to theory during the explanation. In this post, I will show 1D bar element and the method of basic programming it in C#. I assume you want to learn C# and FEM so I will try to say about both of them simultaneously. First thing first! The task is to calculate 1D bar, like on this figure: For simplification, we assumed: this is simple bar element, only compression or tension is allowed, there is no gravity, the deformation can be only according to the one direction (X). Th