Experimental Modal Analysis
Modal data describe the dynamic properties of a structure and can assist in the design of almost any structure, helping to identify areas where design changes are needed. Predicting the vibration characteristics of components and systems is a standard CAE process in today’s automotive, aerospace, or MEMS development environment. Laser vibrometry can make the same measurements as accelerometers but more quickly and accurately, substantially cutting modal testing costs.
The development of a modal model, from either frequency response measurements or from a finite element model, is useful for simulation and design studies. One of these studies is structural dynamics modification. This is a mathematical process which uses modal data (frequency, damping and mode shapes) to determine the effects of changes in the system characteristics due to physical structural changes. These calculations can be performed without actually having to physically modify the actual structure until a suitable set of design changes is achieved.
Laser scanning vibrometry is ideally suited for modal tests because it provides an unambiguous phase reference, highly precise measurement data without mass loading problems and a high spatial resolution for detailed FEM correlations. Both complete and partial data sets can be exported to commercially available software packages for experimental modal analysis (LMS, ME’scope, and others).
To learn more about the theory behind this method, please read our tutorial “Basics of Experimental Modal Analysis”.