FEM for trusses

This chapter discusses the development of a finite element method (FEM) for truss members. The element developed is commonly known as the truss element or bar element. Such elements are applicable for the analysis of the skeletal type of truss structural systems both in two-dimensional planes and in three-dimensional space. In planar trusses there are two components in the x and y directions for the displacements as well as for the forces. However, for space trusses there will be three components in the x , y , and z directions for both displacements and forces. For truss members that are free of body forces, there is no need to use higher order elements, as the linear element can already give the exact solution. However, for truss members subjected to body forces arbitrarily distributed in the truss elements along its axial direction, higher order elements can be used for more accurate analysis. The procedure for developing such high order one-dimensional elements is the same as for the linear elements. The only difference is the shape functions.