Vibrations of One and Two Degree-of-Freedom Systems

Abstract

In this chapter, we focus on the motion of the structure and study how it responds to an external force. In particular, we study the classical vibrations problem in which a mass is supported by a spring and a damper (known as a mass-spring-damper system) and is free to oscillate. We discuss the cases of a one-degree-of-freedom (1 DOF) and a 2 DOF vibratory systems. There is no fluid involved in a classical vibrations problem. In the very last section of this chapter, we will study the response of a mass-spring-damper system when it is placed in otherwise still fluid to study how the presence of fluid around a vibrating system affects its motion. We call this “otherwise still fluid” to emphasize that before the structure starts to oscillate, the fluid is at rest, and it starts moving only because the structure is moving. This will be the first fluid-structure interaction system that we will study in this book.