# Computational Modelling of a Prestressed Tensegrity Core in a Sandwich Panel

## TL;DR

This paper introduces a computational method to model tensegrity cores in lightweight sandwich panels, showing how prestress affects their stability and stiffness.

## Contribution

A novel finite element modeling approach combining prestress analysis and software implementation for tensegrity sandwich panel cores is presented.

## Key findings

- Model M1 showed constant stiffness regardless of prestress, while M2 exhibited variable stiffness depending on prestress.
- M2's nonlinear behavior and sensitivity to prestress make it suitable for adaptive structures.
- Prestress significantly impacts the stability of tensegrity sandwich panel cores.

## Abstract

Tensegrity structures, by definition composed of compressed members suspended in a network of tensile cables, are characterised by a high strength-to-weight ratio and the ability to undergo reversible deformations. Their application as cores of sandwich panels represents an innovative approach to lightweight design, enabling the regulation of mechanical properties while reducing material consumption. This study presents a finite element modelling procedure that combines analytical determination of prestress using singular value decomposition with implementation in the ABAQUS™ 2019 software. Geometry generation and prestress definitions were automated with Python 3 scripts, while algebraic analysis of individual modules was performed in Wolfram Mathematica. Two models were investigated: M1, composed of four identical modules, and M2, composed of four modules arranged in two mirrored pairs. Model M1 exhibited a linear elastic response with a constant global stiffness of 13.9 kN/mm, stable regardless of the prestress level. Model M2 showed nonlinear hardening behaviour with variable stiffness ranging from 0.135 to 1.1 kN/mm and required prestress to ensure static stability. Eigenvalue analysis confirmed the full stability of M1 and the increase in stability of M2 upon the introduction of prestress. The proposed method enables precise control of prestress distribution, which is crucial for the stability and stiffness of tensegrity structures. The M2 configuration, due to its sensitivity to prestress and variable stiffness, is particularly promising as an adaptive sandwich panel core in morphing structures, adaptive building systems, and deployable constructions.