Analysis of clustered tensegrity structures using a modified dynamic relaxation algorithm

Abstract

a b s t r a c tTensegrities are spatial, reticulated and lightweight structures that are increasingly investigated as structural solutions for active and deployable structures. Tensegrity systems are composed only of axially loaded elements and this provides opportunities for actuation and deployment through changing element lengths. In cable-based actuation strategies, the deficiency of having to control too many cable elements can be overcome by connecting several cables. However, clustering active cables significantly changes the mechanics of classical tensegrity structures. Challenges emerge for structural analysis, control and actuation. In this paper, a modified dynamic relaxation (DR) algorithm is presented for static analysis and form-finding. The method is extended to accommodate clustered tensegrity structures. The applicability of the modified DR to this type of structure is demonstrated. Furthermore, the performance of the proposed method is compared with that of a transient stiffness method. Results obtained from two numerical examples show that the values predicted by the DR method are in a good agreement with those generated by the transient stiffness method. Finally it is shown that the DR method scales up to larger structures more efficiently.

Deployment of a Tensegrity Footbridge

“…Rhode-Barbarigos et al (2012b) then studied several deployment methods and showed that utilizing springs, inspired from (Schenk et al 2007), and clustered-cables reduces the number of actuators required for controlled deployment. Bel Hadj Ali et al (2011) proposed an analysis method for clustered tensegrity structures through a modified dynamic relaxation algorithm. Clustered cable elements run continuously through nodes.…”

“…A detailed presentation of the modified DR method can be found in (Bel Hadj Ali et al 2011). The numerical model does not include the dimensions of joints and consequently, there are modelling challenges associated with eccentricity, friction and the effect of strut contact on deployment.…”

Mallas tensegríticas de doble capa y manipulaciones de Rot-Umbela

“…El autor querría agradecer la desinteresada y generosa colaboración de Julien Aversen y Landolf Rhode-Barbarigos, poniendo a disposición para esta investigación herramientas de gran utilidad para el análisis de las estructuras aquí expuestas, como son respectivamente el ToyGL (84) y el algoritmo de relajación dinámica modificada (83).…”

Determining control strategies for damage tolerance of an active tensegrity structure

“…Structural analyses for various load combinations were performed using dynamic relaxation [36]. Analysis results were used to check safety and serviceability requirements.…”

“…Moored and BartSmith investigated actuation on a simple tensegrity beam with groups of individual active cable elements that are combined into continuous cables. Bel Hadj Ali et al [36] proposed a modified dynamic relaxation algorithm for static analysis of tensegrity structures including continuous cables. Apart from the numerical example presented in [36,37], no study addressing structural control employing continuous cables for large tensegrity structures is available in the literature.…”