Effective Beam Stiffness Properties of n-Strut Cylindrical Tensegrity Towers

In this paper, a method to obtain effective continuum beam stiffness properties of tensegrity towers with struts in each bay is developed. Long tensegrity towers for space applications can be modeled as beam-like structures, and axial, bending, shear, and torsional stiffness properties can be used to make comparisons between alternatives to determine the optimum design for a mission. Continuum beam models and effective stiffness properties of Class-2 tensegrity towers are obtained using a modified energy equivalency approach. Self-stress levels (i.e., cable tension and strut compression) are varied to observe their influence on the effective stiffness properties. Axial and torsional rigidities are found to be highly affected by the self-stress level, while bending and shear rigidities are not affected as much. The obtained effective stiffness properties are validated with nonlinear finite element analyses. With these properties, alternative tower designs for a specific application can be readily evaluated without the need for numerous computationally expensive structural analyses.