The document discusses the finite element method (FEM), a numerical technique used to solve complex engineering problems. FEM was originally developed for aerospace engineering but is now widely used in civil, mechanical, and electrical engineering. It works by dividing a structure into finite elements and obtaining an approximate solution by analyzing the properties of individual elements and their interaction. The key principles of FEM include using computational methods to solve boundary value problems representing physical structures, with field variables governed by differential equations and boundary conditions specified on the field boundaries.