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Automated Manufacturing of Grid Stiffened Panels with Radically Reduced Tooling


Title: Automated Manufacturing of Grid Stiffened Panels with Radically Reduced Tooling

Authors: Harry Ratkai, Sumaiya S. Tanu, Donald W. Radford

DOI: 10.33599/nasampe/c.23.0185

Abstract: Grid-stiffened continuous fiber reinforced composite panels are an attractive option for creating lightweight structures due to the tailorability for various applications and the resulting high specific properties. However, the panel stiffeners and stiffener intersections result in high tooling complexity and correspondingly high cost of implementation. These factors have limited the impact of such structures in the composites industry. Previous research has demonstrated the ability to produce high quality, high aspect ratio beams representative of individual grid stiffeners, using E-glass/PET comingled tow via direct digital manufacturing. Further, prior preliminary efforts have demonstrated the potential to use the same approach to manufacture grid intersections that have continuous fiber in both directions. To expand on the previous efforts in grid stiffeners produced by direct digital manufacture with radically reduced tooling requirements, this effort compares two methods of providing positioning and consolidation, nozzle vs. roller. Both processes are based on a commingled yarn feedstock. The extrusion through a nozzle has been shown to enable grid intersection control through local variations in applied consolidation and will serve as the baseline process. However, this approach requires a continuous placement path to create the complete grid-stiffened panel, as no mechanism for cutting and restarting has been implemented. Alternatively, a newly developed placement head incorporating cut and refeed, mounted to a 6-axis robot, offers the potential for improved path placement efficiency. The two techniques are used to produce similar grid composite stiffeners to evaluate the effectiveness of producing the grid intersections. The rate of deposition of the two end effectors are compared, and the quality of the associated grid stiffeners, and intersections, are determined through measurement of geometry, fiber volume fraction, and void fraction.

References: [1] M. Huybrechts, et al., Grid Stiffened Structures: A Survey of Fabrication, Analysis and Design Methods, ICCM/12, 1999. [2] Zhao, Cong, et al., Influences Of Ply Waviness And Discontinuity On Automated Fiber Placement Manufactured Grid Stiffeners. Composite Structures 256, 2021. [3] S.M. Huybrechts, et al., Manufacturing Theory For Advanced Grid Stiffened Structures. Composites Part A: Applied Science and Manufacturing 33.2, pp. 155-161, 2002. [4] M. Buragohain, and R. Velmurugan, Study Of Filament Wound Grid-Stiffened Composite Cylindrical Structures, Composite Structures, Volume 93, Issue 2, 2011, [5] Y. G. Lee, et al., Compressive Strength Stabilizing Manufacturing Method Of Anisogrid Composite Structure Ribs Without An Outer Skin. Compos. Part B Eng., vol. 203, Dec. 2020. [6] H. Ahmadi and G. Rahimi, Analytical and experimental investigation of transverse loading on grid stiffened composite panels, Compos. Part B Eng., vol. 159, pp. 184–198, Feb. 2019. [7] S. Shroff, E. Acar, and C. Kassapoglou, Design, Analysis, Fabrication, And Testing Of Composite Grid-Stiffened Panels For Aircraft Structures. Thin-Walled Struct., 2017. [8] Z. Qureshi, et al., In Situ Consolidation Of Thermoplastic Prepreg Tape Using Automated Tape Placement Technology: Potential And Possibilities. Compos. Part B Eng., 2014. [9] G. Gardiner, Integrating Antennas Into Composite Aerostructures, Composites World, 2021. [10] P. A. Rodriguez, Dynamic Mechanical Analysis For Quality Evaluation Of Additively Manufactured Continuous Fiber Reinforced Thermoplastic Matrix Composites Subject To Manufacturing Defects, Master’s Thesis, Colorado State University, 2019. [11] S. Hogan and D.W. Radford, Direct Digital Manufacture of Continuous Fiber Reinforced Thermoplastic High Aspect Ratio Composite Grid Stiffeners with Radically Reduced Tooling, CAMX’22, Anaheim, California, United States, 2022. [12] L. Zhang, et al., Review Of Automated Fibre Placement And Its Prospects For Advanced Composites, J. Mater. Sci., vol. 55, no. 17, pp. 7121–7155, 2020. [13] K. M. Warlick and D. W. Radford, Tow Positional Fidelity In A Continuous Fiber/3D Printing Approach On A Curved Surface. CAMX’17, Orlando, Florida, 2017. [14] M.E. Bourgeois, M.E., and D. Radford, Out of Plane Placement of Tensioned Commingled Roving Creating Truss Sandwich Panels. CAMX, 2019, Dallas. Texas, 2019. [15] “ASTM D792-20 Standard Test Methods for Density and Specific Gravity of Plastics"". [16] “ASTM D3171-15 Standard Test Methods for Constituent Content of Composite Materials"". [17] A. Gleadall, Fullcontrol Gcode Designer: Open-Source Software For Unconstrained Design In Additive Manufacturing, Additive Manufacturing, vol. 46, 2021

Conference: CAMX 2023

Publication Date: 2023/10/30

SKU: TP23-0000000185

Pages: 15

Price: $30.00

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