Geometrical non-linear analysis of tensegrity systems

A calculation method for structures with large deformations and displacements, based on works by Bathe [7-9], is developed so as to determine the tangent stiffness matrix and the internal stress vector. The formulation is established for a 'bar' element. Application of this method for tensegrity systems allowed the study of behaviour for a simple self-stressed system, the four-strut tensegrity system, in case of 'traction, compression, flexion and torsion' loading. Except for compression, the structure is rigidified when the loads increase. Influence of the self-stress level on this behaviour is also evaluated. Secondly a structure, generated by assembly of several four-strut tensegrity systems, has been calculated only under traction, concentrated and distributed. The behaviour under uniformly distributed load can be related to the 'isolate' cell behaviour, even if some difficulties appear, mainly because of boundary conditions. and possible choices for common cables between two adjacent cells. (C) 1999 Elsevier Science Ltd. All rights reserved.