Mechanical Vibrations: Theory and Practice

9

Fundamentals of Experimental Modal Analysis

9.1 INTRODUCTION

Modal analysis is a technique to find the intrinsic properties of components of a machine/structure in terms of their natural frequencies and the mode shapes in each natural frequency mode of vibrations. We know that these largely depend upon the mass distribution, deformations, as well as the damping in the system. For simplicity, we generally ignore the internal damping in the system. We shall explain the basic concepts of modal analysis by analysing the modes of vibration of a simple plate, which is freely suspended as shown in Fig. 9.1.

Figure 9.1 Modal Analysis of a Plate