Basics

When solving for the various items of interest using the finite element method (FEM) such as displacement, stress, and strain, it is important to understand the basics of what is happening when you start pressing the various mesh, boundary condition, and solve buttons. In software, these perform very complicated versions of the basics tasks outlined below.

At the most basic level, the FEM discretizes something into a set of nodes which form elements. The simplest form is a bar element, which represents a 1 dimensional spring with a node at either end and an element between the nodes with stiffness k. This stiffness can be a spring constant k, or if the model represents a real object such as a square bar , k can be calculated from the objects material properties and geometry.

Fig 1. Example bar element