Dynamics Analysis on Planar Articulated Trusses Considering Cubic Nonlinearity of Joints

A large number of joints that make possible the smooth deployment of an articulated truss may lead to the unexpected variation of the whole dynamic characteristics of the truss. In this paper, attention is focused on exploring the joint characteristics and their effects not strictly following the conventional linear assumption. Particularly, the effects of cubic nonlinear characteristics of joints on the dynamic behavior of articulated trusses are investigated. First, the equivalent dynamic model of the truss cell in the frequency domain is developed for enhancing the computational efficiency. With the employment of the describing function method (DFM), the frequency responses of the planar articulated truss considering the cubic nonlinearity of joints are obtained analytically. Moreover, the transient responses of the articulated truss under external shock loads are obtained numerically. Subsequently, the variations in frequency obtained by the fast Fourier transformation (FFT) of the numerical results show consistent tendency compared with those obtained by the equivalent dynamic model of the planar articulated truss. Finally, several conclusions are presented at the end.