A Study on the Effects of Frequency contents of External Disturbances on the Input Energy

During past decades, remarkable studies have been devoted to the construct an energy based design guideline. But because the presence of numerous unknowns, it has not yielded tangible advances. Previous studies indicate that the amounts of input energy as well as variation of its quantity depend onthe characteristics of ground acceleration and dynamic properties of structures. In this paper, to provide a precise insight to the effects of such factors, mainly the frequency contents of input excitation, a detailed study is carried out. The structure is idealized as a single degree of freedom. Also a harmonic sinusoidalload with different frequency contents is used as external disturbances. Extensive analysis show that the input energy doesn’t maximum on the resonant frequency precisely, moreover damping ratio only effective in limited margin, around dominant frequency, even beyond this border increasing damping ratio leads to unfavorable results

Keywords:

input energy , frequency content , damping ratio , single degree of freedom