SPECTRAL-ANALYSIS OF SYSTEMS WITH NONCLASSICAL DAMPING USING CLASSICAL MODE SUPERPOSITION TECHNIQUE

A spectral method for random vibration analysis of a structural system with non-proportional damping is presented using classical (undamped) mode superposition technique. The method obtains the frequency respon se function of the system by solving the dynamic equilibrium equations in generalized co-ordinates through an iterative process. The iterati ve solution is written in closed form and the proof for convergence of the iterative process is given. Numerical examples show the convergen ce characteristics of the process and an excellent accuracy of the obt ained results. The method turns out to be computationally more efficie nt than the conventional methods of spectral analysis using damped mod e shapes and frequencies.