Speaker
Description
In lightweight bar-membrane structures, it is essential to shape their joints properly. Especially in tensegrity structures, the reliability of such a connection plays a key role. This work aims to perform numerical and experimental analysis of selected bar-membrane joints that can be used in tensegrity systems. Despite the textile used for the membrane is a nonlinear material it can be linearized assuming it will perform in a specific range of tension thus a linear orthotropic material model may be justified here.
Two polyvinyl chloride (PVC) coated high-tenacity polyester fiber textiles: Serge Ferrari® Flexlight Perform 502S2 and Serge Ferrari® Flexlight Classic 402N were considered for the membrane part of the tensegrity structure. Uniaxial tensile tests on those two materials were performed using Zwick/Roell Z-20 tensile testing machine to determine the tensile strength in warp and fill directions according to the PN-EN ISO 1421:2017-02 code. Based on those results, biaxial non-destructive tensile tests were performed using a BIAX 020 testing machine (Zwick/Roell, Germany) equipped with a video-extensometer to identify the orthotropic material parameters following methods A, C, and D according to the PN-EN 17117-1:2019-02 code. All samples were cruciform shaped with arms parallel to the fabric’s warp and fill so that warp and fill directions were aligned with tension axes during the tests. Then, finite element method (FEM) models simulating biaxial tensile tests were prepared and analyzed using the identified material parameters to validate the adopted numerical model. All numerical analyses were performed using the Hexagon® Marc/Mentat 2024.2 software and correlation coefficients were calculated.
After determining the parameters for linear orthotropic material and obtaining satisfactory convergence between the numerical results and the experimental data, an initial FEM analysis of the selected membrane tensegrity structure was performed to estimate the forces that may occur in the bar-membrane joint. Based on that data, detailed models representing the selected variants of the joints were prepared and analyzed numerically. Finally, analogous experiments were performed in the laboratory. The experimental results were compared with the numerical model and showed relatively high convergence.
ACKNOWLEDGEMENTS
Financial support of these studies from the Gdańsk University of Technology by the DEC-7/2022/IDUB/III.4.3/Pu grant under the Plutonium Supporting Student Research Teams - ‘Excellence Initiative - Research University’ program is gratefully acknowledged.
