ABSTRACT
In this section, we shall formulate finite element equations that include the inertial forces that have been neglected up to now.
The most direct way of discovering suitable equations governing motion is to concentrate the total mass at node points and apply d’Alembert’s principle. Consider, for example, the solution of the plane problem using the rectangular elements (Section 5.1.4). A typical node arrangement is shown in Figure 10.1. The total mass of the material surrounding a node, shown by dashed lines, is treated as a point mass at that node.
