Statistical Analysis of Large Format Additively Manufactured Polyethylene Terephthalate Glycol with 30% Carbon Fiber Tensile Data

Katie A Martin; Jedadiah F Burroughs; Guillermo A Riveros

doi:10.3390/polym16192812

Statistical Analysis of Large Format Additively Manufactured Polyethylene Terephthalate Glycol with 30% Carbon Fiber Tensile Data

Polymers (Basel). 2024 Oct 4;16(19):2812. doi: 10.3390/polym16192812.

Authors

Katie A Martin¹, Jedadiah F Burroughs¹, Guillermo A Riveros²

Affiliations

¹ Geotechnical and Structures Laboratory (GSL), US Army Corps of Engineers (USACE) Engineer Research and Development Center (ERDC), 3909 Halls Ferry Rd., Vicksburg, MS 39180, USA.
² Information Technology Laboratory (ITL), US Army Corps of Engineers (USACE) Engineer Research and Development Center (ERDC), 3909 Halls Ferry Rd., Vicksburg, MS 39180, USA.

Abstract

In large format additive manufacturing (LFAM), a keener understanding of the relationship between the manufacture method and material temperature dependency is needed for the production of large polymer parts. Statistical analyses supported by material properties and a meso-structural understanding of LFAM are applied to elucidate tensile data trends. The data from LFAM polyethylene terephthalate glycol with 30% carbon fiber (CF) (PETG CF30%) panels (diagonal, horizontal, and vertical in the x-y print plane) and injection-molded specimens tensile tested at six different testing temperatures (room temperature, 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C) were used for statistical analyses. A standard deviation, a coefficient of variation, and a two-way and one-way analyses of variance (ANOVA) were conducted. The manufacturing method (44.2%) and temperature (47.4%) have a strong effect on the ultimate tensile strength, in which temperature (82.6%) dominates Young's modulus. To explain the difference between the ultimate tensile strength of vertical, diagonal, and horizontal specimens at room temperature, a visual inspection of the specimen failure was conducted and the maximum stress at the crack tip was calculated analytically. The decreased strength in the diagonal specimens resulted from the reliance on interlaminar adhesion strength. Future work will consider the effect of the void space variation on tensile strength variance.

Keywords: ANOVA; additive manufacturing (AM); carbon fiber (CF); composites; large-format additive manufacturing (LFAM); polyethylene terephthalate glycol (PETG); statistical analysis; stress concentration; ultimate tensile strength; void space.

Grants and funding

The authors acknowledge the financial support provided by the U.S. Army Engineer Research and Development Center under Work Unit “Design-by-analysis Methods for Large Scale Additive Manufacturing”. Permission was granted by the directors of the Information Technology and Geotechnical and Structural Laboratory to publish this information. The findings of this report are not to be construed as an official Department of the Army position unless designated by other authorized documents. The specification of the materials and equipment used should not be construed as the endorsement of said equipment and materials. This work is declared a work of the U.S. Government and is not subject to copyright protection in the United States. This was approved for public release; distribution is unlimited.