Vibration of a two-member open frame

The dynamics of a two-member open frame structure undergoing both in- and out-of-plane motion is examined. The frames are modelled using the Euler–Bernoulli beam theory and are further generalized by permitting an arbitrary angle between the beams and the attachment of a payload at the end of the second beam. The equations of motion are derived using Hamiltonʹs principle and the orthogonality conditions are presented. It is shown that the in- and out-of-plane motions can be decoupled by including the axial deformation components in the assumed displacement fields. The natural frequencies of the system and the contribution of each member into the system potential energy are examined via numerical examples.