Output-Only Modal Identification of Tensegrity Structures

Abstract

Tensegrity systems are a special class of spatial reticulated structures that are composed of struts in compression and cables in tension. In this paper, the performance of stochastic subspace algorithms for modal identification of complex tensegrity systems is investigated. A sub-class algorithm of the Stochastic Subspace Identification family: the Balanced Realization Algorithm is investigated for modal identification of a tripod simplex structure and a Geiger dome. The presented algorithm is combined with a stabilization diagram with combined criteria (frequency, damping and mode shapes). It is shown that although the studied structures present closely spaced modes, the Balanced Realization Algorithm performs well and guarantees separation between closely-spaced natural frequencies. Modal identification results are validated through comparisons of the correlations (empirical vs. model based) showing effectiveness of the proposed methodology.

Estimation of local failure in tensegrity using Interacting Particle-Ensemble Kalman Filter

“…Adopted ST is a cylindrical tensegrity with 3 bars and 6 cables, whereas the EOT is a spherically symmetric tensegrity with 6 bars and 24 cables. The algorithm (Appendix A) to obtain initial statically stable coordinates has been verified with [7]. All the members, cables and bars, of both the tensegrities are assumed to be made of steel (modulus of elasticity = 200GP a).…”

Damage Detection in Tensegrity Using Interacting Particle-Ensemble Kalman Filter

“…The initial statically stable coordinates (see Fig. 2) are obtained from [10]. The stable form of the simplex is further excited with an ambient WGN forcing of variance 10 4 N throughout the simulation.…”