AXIAL DEFORMATION OF SPINE BIO-TENSEGRITY MODEL AT DIFFERENT DEPLOYABLE SCHEMES

The study presents the axial deformation of a spine bio-tensegrity model through a shape change strategy with different deployment schemes. The spine biotensegrity model mimics a human spine's total height, tapered form and natural curvature. Three deployable schemes S1-S3 with a different combination of cables at alterable and fixed lengths were investigated to achieve a series of axial displacements at 200 mm, 400 mm and 600 mm in the z-direction. The shape change algorithm was developed to optimise the forced elongation of cables, incorporating an objective function designed for monitored nodes in the system to reach their prescribed targets during the optimisation process. Sequential quadratic programming was employed to solve a nonlinear analysis. The efficiency of the deployable systems was assessed based on the deformed shapes, convergence curve, and axial forces of the spine biotensegrity model. The finding shows that in addition to axial deformation, the model S1 deployment scheme preserves the slenderness characteristic of the spine. In contrast, the model exhibits excessive expansion in the thoracic region in schemes S2 and S3. Greater total computational steps in deployment scheme S3, followed by S2 and S1, reveal that the active cables set near the monitored nodes allow the model to sense and act faster to reach their targets. The study contributes to understanding the structural behavior and deployment strategy for a structure mimicking a biological system and it can be extended to applications such as deployable structures and biomechanical studies.