Free and Forced Vibrations of Elastically Connected Double-beam Systems

The free vibrations and forced vibrations of a system comprising two elastically-connected parallel upper and lower beams having unequal masses and unequal flexible rigidities are analysed using a generalised method of finite integral transformation and the Laplace transformation. The natural frequencies and the amplitude ratios for the normal modes of vibration are presented; it is also shown that a system comprising a lower beam and coupling springs can be used as a dynamic vibration absorber to reduce the vibrations of an upper beam that is subjected to a periodic force.