FRF-Based Modal Analysis
Modal analysis is used to characterize resonant vibration in mechanical structures. Each resonance has a specific “natural” or modal frequency, a modal damping or decay value, and a mode shape. FRF-Based parameter estimation (or curve fitting) is used to estimate the modal parameters of a structure from a set of FRFs. At the heart of the Basic Modal Analysis option is the ME’scope Polynomial method, an easy to use MDOF curve fitter. This curve fitter can be used to simultaneously extract parameters for multiple modes, especially in cases of high modal density. It can also extract local modes where the resonant vibration is confined to a local region of the structure. The Multi-Reference Modal Analysis option contains all of the features of the Basic Modal Analysis option, plus additional methods for curve fitting a multiple reference set of FRFs. Multi- Reference curve fitting is used to extract closely coupled modes and repeated roots (two or more modes at the same frequency). This option contains a Stability diagram for locating stable pole estimates, and three additional curve fitting methods: Complex Exponential, Z-Polynomial, and the patented AF Polynomial method.