Modal Analysis

  • Thomas D. Rossing


Modal analysis is widely used to describe the dynamic properties of a structure in terms of the modal parameters: natural frequency, damping factor, modal mass and mode shape. The analysis may be done either experimentally or mathematically. In mathematical modal analysis, one attempts to uncouple the structural equations of motion so that each uncoupled equation can be solved separately. When exact solutions are not possible, numerical approximations such as finite-element and boundary-element methods are used.

In experimental modal testing, a measured force at one or more points excites the structure and the response is measured at one or more points to construct frequency response functions. The modal parameters can be determined from these functions by curve fitting with a computer. Various curve-fitting methods are used. Several convenient ways have developed for representing these modes graphically, either statically or dynamically. By substituting microphones or intensity probes for the accelerometers, modal analysis methods can be used to explore sound fields. In this chapter we mention some theoretical methods but we emphasize experimental modal testing applied to structural vibrations and also to acoustic fields.


Mode Shape Frequency Response Function Sound Field Modal Assurance Criterion Fast Fourier Transform Analyzer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.





analog-to-digital converter


boundary-element method


direct current


degree of freedom


digital speckle interferometry


electronic speckle-pattern interferometry


finite-element analysis


finite-element method


fast Fourier transform


frequency response function


International Modal Analysis Conference


impulse response function


modal assurance criterion


multiple degree of freedom


microelectromechanical system


multiple-input multiple-output


operating deflexion shape






unit modal mass


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Copyright information

© Springer-Verlag 2014

Authors and Affiliations

  1. 1.Center for Computer Research in Music and Acoustics (CCRMA) Department of MusicStanford UniversityStanfordUSA

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