• Dr. Sushila Rani

Modal analysis/ testing is an experimental technique used to derive the modal model of a linear time-invariant vibratory system. The theoretical basis of the technique is establishing a relationship between the vibration response at one location and excitation at the same or another location as a function of excitation frequency. This relation is known as frequency response function (FRF). A frequency response function (FRF) captures the unique dynamic characteristics of the structure between two degrees of freedom (DOFs); the response DOF and the excitation DOF. The modal properties of structures are extracted from resultant FRF’s through Global Rational Fraction Polynomial method (GRFP) or curve fitting. Modal parameters are global properties of the structure. The changes in modal parameters may be used to locate structural faults. The structure faults occurred locally, but the modal parameters changes all over the structure. A case study of a cantilever beam is presented in order to evaluate its modal properties and detect failure zone. The experimental modal analysis of a cantilever beam has been carried out using vibration analyzer OROS®. The frequency response functions (FRFs) of the cantilever beam are obtained as output results, and its modal properties are determined by applying Global Rational Fraction Polynomial method (GRFP) on resultant FRFs.

– Modal analysis, Mild steel cantilever beam, Global Rational Fraction Method (GRFP), Modal properties, Frequency Response Function (FRF).

"ESTIMATION OF MODAL PARAMETERS FROM FREQUENCY RESPONSE FUNCTION THROUGH GLOBAL RATIONAL FRACTION POLYNOMIAL METHOD (GRFP)", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.5, Issue 4, page no.58-62, April-2018, Available :http://www.jetir.org/papers/JETIR1804014.pdf

"ESTIMATION OF MODAL PARAMETERS FROM FREQUENCY RESPONSE FUNCTION THROUGH GLOBAL RATIONAL FRACTION POLYNOMIAL METHOD (GRFP)", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.5, Issue 4, page no. pp58-62, April-2018, Available at : http://www.jetir.org/papers/JETIR1804014.pdf