Large space truss structures (LSTS) are essential load‐bearing components in many spacecraft. Owing to their large size, lightweight design, and high flexibility, they inherently exhibit very low natural frequencies and small damping ratios, making them susceptible to persistent vibrations induced by small disturbances. To address this issue, this study investigates a piecewise LSTS with tunable spring–damper joints, which both reflects the segmented assembly characteristics in practice and captures the interface discontinuities that significantly affect vibration characteristics. An analytical framework for the axial vibration of a piecewise elastic bar is developed using Hamilton′s principle in a dimensionless form, whereas the boundary and transition conditions are obtained from the principle of minimum potential energy. The resulting characteristic equations are solved to determine the natural frequencies and discontinuous mode shapes, and the framework is further extended to forced vibration under harmonic and transient excitations. The analytical solutions are validated against finite element results, with relative errors in the first eight modes remaining below 1.3%. The results show that, compared with an equivalent uniform truss/bar, segmentation with compliant joints further reduces the natural frequencies because of local stiffness loss at the interfaces. Nevertheless, the displacement discontinuities at the joints localize elastic potential energy in the springs and enable its dissipation by the dampers, thereby reducing both steady‐state and transient responses.
Zeng et al. (Thu,) studied this question.