Abstract
Measuring the geometric imperfections in cylindrical shells is a critical step necessary to create accurate numerical models that can capture the imperfection-sensitive behavior of these structures. Modern composite structures, such as variable–angle filament–wound (VAFW) cylinders, have a unique imperfection signature that is still unknown to the scientific community. This new class of variable–stiffness structures developed by our research group combines wide tailoring capabilities with the efficient manufacturability enabled by filament winding process. The present study proposes a novel imperfection measurement method that is simple and applicable to both small and large structures. The topographic data is measured with only a pair of cameras. Practical aspects of using digital image correlation (DIC) are described and discussed in detail, such as lighting, focus adjustment, and calibration. State–of–the–art best–fit routines, based on least–squares optimization, are used to transform raw data into a common coordinate system. Finally, the transformed data is stitched to build a full 3D imperfection pattern that can be readily used in a nonlinear finite element analysis. The developed method is used to measure the imperfections of 12 VAFW cylinders. The mass of the cylinders is used to validate the geometric imperfections and evaluate the variability of the proposed methodology.
Original language | English |
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Article number | 114497 |
Number of pages | 13 |
Journal | Composite Structures |
Volume | 276 |
Early online date | 10 Aug 2021 |
DOIs | |
Publication status | Published - 15 Nov 2021 |
MoE publication type | A1 Journal article-refereed |
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VAFW cylinders 2020, S1, S2, S4, S8, stitched imperfections
Castro, S. G. P. (Creator) & Almeida Jr, H. (Creator), Zenodo, 2021
DOI: 10.5281/zenodo.4488648, https://doi.org/10.5281/zenodo.4581164
Dataset
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VAFW cylinders 2020, S1, S2, S4, S8, DIC raw data
Castro, S. G. P. (Creator) & Almeida Jr, H. (Creator), Zenodo, 2021
Dataset