The system input and output signals collected in the experimentare subjected to parameter identification to obtain modal parameters, which is called experimental modal analysis. The ultimate goal of modal analysis is to identify the modal parameters of the system, and provide a basis for structural vibration analysis, vibration fault diagnosis and prediction, and optimal design of structural dynamic characteristics.
Modal analysis can help users to evaluate the dynamic features of available structure, control the radiation noise of structure, reduce the product’s noise level, find out the source of vibration noise, conduct structural dynamic modification and product optimization design, verify the finite element model, raise the precision of digital model, etc.
Modal analysis allows users to have a deep understanding of the systematic dynamic characteristics of products and to enable systematic dynamic design to bring about positive influence on the decision-making for product development.
Modal analysis is divided into computational modal analysis and test modal analysis. If modal parameter is computed through finite element method, it shall be referred to as computational modal analysis. If the data are obtained through sensor and data acquisition equipment before obtaining modal parameter through parameter identification, it shall be referred to as test modal analysis.
Test model and computational modal are both related and different. In the early stage of test model, computational modal analysis can help finalize the distribution of measuring points during test and the position of reference point, etc. In the later stage, the test model result can be used for correcting the finite element modal to make the model more accurate.
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LMS modal test analysis system |
Modal test of a track gear box |
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Finite element analysis |
Simulation |
