Determination of modal characteristics from random response signal

This paper deals with three procedures that are used to13; predict the response characterstics of Aeroelastic 'models and flight vehicles from response data. These three 13; -. 1. Power Spectral Density 2 . Autocorrelation 3 . Randorn Decrenent method. The relative merits of each inethod are based on analysing the linear structural response data obtained from random excitation or step force or an impulsive force. Aerospace vehicles are excited by natural turbulence or Random noise of constant PSD that exists in the wind tunnel or in the atmosphere. These methods are successfully used to measure the natural frequency and damping of the structure in each mode of excitation. Implimentation and Application of each method are discussed. Some results and comparisons between methods are presented