Finite Element Method with Applications in Engineering

6.3 TRUSS ELEMENT

Lattice transmission towers, steel truss bridges or roof support systems can be modelled accurately by employing truss elements. In this section, the element stiffness matrix is derived for a linear-elastic truss (or bar) element. Local and global co-ordinate systems are introduced to facilitate the formulation. Each element has its own local co-ordinate system which is designated by lower case letters, x, y, z whereas the global co-ordinate system (i.e., reference co-ordinate) is indicated by upper case letters X, Y, Z (Figure 6.9(a)). Similarly, the displacement components with respect to local co-ordinate system are indicated by the lower case letters u, v, w and those in the global co-ordinate system are shown by the upper ...