Modal data deals with the dynamic properties of a structure and can help in the design of almost any structure, facilitating to detect areas where design changes are required. Determining the vibration characteristics of systems and components is a standard CAE process in today’s aerospace, automotive, or MEMS development environment. Similar to accelerometers, laser vibrometry can be used to make the same measurements but more accurately and quickly, significantly cutting modal testing costs.
The development of a modal model, from a finite element model or from frequency response measurements, is useful for design and simulation studies. One of which is the structural dynamics modification. This is a mathematical process employing modal data (damping, frequency, and mode shapes) to determine the effects of changes in the system characteristics due to changes in the physical structure. These calculations can be carried out by avoiding physical modification of the actual structure until a suitable set of design changes is achieved.
Laser scanning vibrometry is perfect for modal tests as it provides an unambiguous phase reference, a high spatial resolution for detailed FEM correlations, and highly precise measurement data with no mass loading problems. Both partial and complete data sets can be exported to commercially available software packages for experimental modal analysis (LMS, ME’scope, and others).
Polytec’s tutorial “Basics of Experimental Modal Analysis” offers information about the theory behind this method.
This information has been sourced, reviewed and adapted from materials provided by Polytec.
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