The Fundamentals of Modal Testing

Application Note 243-3 Η(ω) = Σ n r = 1 φ φ i j /m (n-) + (2 n) ω ω ξωω 2 2 2 2 2 Modal analysis is defined as the study of the dynamic characteristics of a mechanical structure. This application note emphasizes experimental modal techniques, specifically the method known as frequency response function testing. Other areas are treated in a general sense to introduce their elementary concepts and relationships to one another. Although modal techniques are mathematical in nature, the discussion is inclined toward practical application. Theory is presented as needed to enhance the logical development of ideas. The reader will gain a sound physical understanding of modal analysis and be able to carry out an effective modal survey with confidence. Chapter 1 provides a brief overview of structural dynamics theory. Chapter 2 and 3 which is the bulk of the note – describes the measurement process for acquiring frequency response data. Chapter 4 describes the parameter estimation methods for extracting modal properties. Chapter 5 provides an overview of analytical techniques of structural analysis and their relation to experimental modal testing.