複合材料纏繞是一種廣泛應用於壓力容器的製程方式。此製程在壓力容器表面形成複雜的纖維重疊，增加了建模的複雜性。因此，大多數研究採用軸對稱分配疊層定義的方法來減少建模的複雜性。本研究旨在為複合材料壓力容器確定從簡化到高精度的疊層定義。根據壓力容器的幾何外型及其纖維繞製或自動纖維鋪放的製程參數開發了一個程式碼，以計算模型中所有有限元素的精確疊層定義。接著，該程式碼通過 k-means 集群法依照指定的解析度對疊層定義進行分類，並將分類後的定義分配給每個元素。為了證明該程式碼的有效性，將其應用於探空火箭燃料桶槽的分析和最佳化自動化過程中。結果表明，在提高準確性的同時，顯著減輕了重量並提高了安全裕度。此外，通過局部提升疊層定義的真實度進行全面重新分析或子模型分析，可以有效提高局部感興趣區域的數值準確性。

Composite wrapping is a widely utilized process for manufacturing pressure vessels. This process results in complex fiber overlaps on the surface of a pressure vessel, complicating the modeling process. Therefore, most studies adopt methods that asymmetrically assign laminate definitions to reduce modeling complexity. This study aims to determine laminate definitions for composite pressure vessels with variable fidelity, from simplification to high accuracy. A computer code was developed to compute precise laminate definitions for all the finite elements of a model according to the geometry of the pressure vessel and its fabrication parameters for filament winding or automated fiber placement. Afterwards, the code classifies the definitions according to specified resolutions by K-means clustering and assign a classified definition to each element. To demonstrate the effectiveness of the code, it was integrated into an automated process for analysis and optimization of a fuel tank of a sounding rocket. The results indicate significant weight reductions and increases in safety margin with improved accuracy. Furthermore, numerical accuracy for local areas of interest can be efficiently raised to a desired level by locally elevating the fidelity of laminate definition for an overall reanalysis or a submodel analysis.

[1] W. Yu Shiuan, "Advanced Analysis Techniques for Continuous Fiber Reinforced Pressure Vessels," 2024.
[2] Y. Shih ting, "Application of Bayesian Optimization (BO) and Finite Element
Analysis to Design Continuous Fiber-reinforced Composite Pressure Vessels," 2024.
[3] M. Azeem et al., "Application of Filament Winding Technology in Composite Pressure Vessels and Challenges: A Review," Journal of Energy Storage, vol. 49, p. 103468, 2022/05/01/ 2022, doi: https://doi.org/10.1016/j.est.2021.103468.
[4] E. Oromiehie, B. G. Prusty, P. Compston, and G. Rajan, "Automated fibre placement based composite structures: Review on the defects, impacts and inspections techniques," Composite Structures, vol. 224, p. 110987, 2019/09/15/ 2019, doi: https://doi.org/10.1016/j.compstruct.2019.110987.
[5] D. McCarville, J. Guzman, A. Dillon, J. Jackson, and J. Birkland, "Design, Manufacture and Test of Cryotank Components," 2017.
[6] A. Air, M. Shamsuddoha, and B. Gangadhara Prusty, "A review of Type V composite pressure vessels and automated fibre placement based manufacturing," Composites Part B: Engineering, vol. 253, p. 110573, 2023/03/15/ 2023, doi: https://doi.org/10.1016/j.compositesb.2023.110573.
[7] J. Rousseau, D. Perreux, and N. Verdière, "The influence of winding patterns on the damage behaviour of filament-wound pipes," Composites Science and Technology, vol. 59, no. 9, pp. 1439-1449, 1999/07/01/ 1999, doi: https://doi.org/10.1016/S0266-3538(98)00184-5.
[8] M. Azeem et al., "Influence of winding angles on hoop stress in composite pressure vessels: Finite element analysis," Results in Engineering, vol. 21, p. 101667, 2024/03/01/ 2024, doi: https://doi.org/10.1016/j.rineng.2023.101667.
[9] Q. Wu et al., "Filament winding analysis and experimental verification of a combined revolution body with a concave surface," Composite Structures, vol. 280, p. 114951, 2022/01/15/ 2022, doi: https://doi.org/10.1016/j.compstruct.2021.114951.
[10] J. Fu, J. Yun, Y. Jung, and D. Lee, "Generation of filament-winding paths for complex axisymmetric shapes based on the principal stress field," Composite Structures, vol. 161, pp. 330-339, 2017/02/01/ 2017, doi: https://doi.org/10.1016/j.compstruct.2016.11.022.
[11] E. A. W. de Menezes, T. V. Lisbôa, J. H. S. Almeida, A. Spickenheuer, S. C. Amico, and R. J. Marczak, "On the winding pattern influence for filament wound cylinders under axial compression, torsion, and internal pressure loads," Thin-Walled Structures, vol. 191, p. 111041, 2023/10/01/ 2023, doi: https://doi.org/10.1016/j.tws.2023.111041.
[12] MATLAB. "k-means clustering - MATLAB kmeans." https://www.mathworks.com/help/stats/kmeans.html (accessed 5 July, 2024).
[13] J. A. Hartigan and M. A. Wong, "Algorithm AS 136: A K-Means Clustering Algorithm," Journal of the Royal Statistical Society. Series C (Applied Statistics), vol. 28, no. 1, pp. 100-108, 1979, doi: 10.2307/2346830.