ABSTRACT
In this chapter we review a few elementary dynamics concepts which are pertinent in the analysis and design of structures with dynamic loadings. These concepts include sudden loadings, natural frequency, and free-fall=impact. We attempt to illustrate the concepts with a few simple examples.
Consider the elementary mass-spring system of Figure 23.1, where a body B with mass m can move left and right over a smooth horizontal surface. The movement of B is restricted by a linear spring with stiffness modulus k. The displacement (or distance) of B away from a neutral (static equilibrium) position is x. An elementary dynamic analysis shows that the differential equation describing the movement of B is [1]:
