PSI - Issue 61

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ScienceDirect

Procedia Structural Integrity 61 (2024) 156–163 Structural Integrity Procedia 00 (2024) 000–000 Structural Integrity Procedia 00 (2024) 000–000

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© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of IWPDF 2023 Chairman Abstract The ASTM D5045 standard is one of the most widely-used and cited methods for estimating the fracture toughness of thermoplas tic materials. It is well-established in the literature that additively-manufactured thermoplastic materials fail to satisfy the criterion in this standard for plane strain condition, but there is also a common observation that there is no a strong dependence of the sample size on the fracture toughness values. The present study explores this question experimentally, examining three common thermo plastic materials (acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polycarbonate (PC)) manufactured using the fused filament fabrication (FFF) process. Di ff erent specimen sizes were used, none of which met the plane strain criterion specified in the standard. Across several replications and analysis of the experimental data, it was found that there was no statistically signif icant e ff ect based on sample size. It was concluded that, at least within the size range and materials studied, there is no significant di ff erence in output values based on sample size and that the tests were repeatable across di ff erent sample sizes. This suggests that either the samples reached plane strain condition at a smaller size than expected by the standard or that there is not a large di ff erence between plane strain and plane stress conditions for FFF-processed CT samples. This fundamental conclusion was that the ASTM D5045 standard is a valid and useful way to test the linear-elastic fracture properties of FFF-processed thermoplastics. © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023. Keywords: Thermoplastic additive manufacturing; fracture testing; design of experiments; fused filament fabrication 3rd International Workshop on Plasticity, Damage and Fracture of Engineering Materials (IWPDF 2023) Impact of Compact Tension Specimen Size on Fracture Toughness of FFF-Processed Thermoplastics Jose Beltra Mira a , Vanessa Restrepo a , Bhaskar Vajipeyajula a , Albert E. Patterson a, ∗ a TexasA & M University, College Station, 77843, Texas, USA Abstract The ASTM D5045 standard is one of the most widely-used and cited methods for estimating the fracture toughness of thermoplas tic materials. It is well-established in the literature that additively-manufactured thermoplastic materials fail to satisfy the criterion in this standard for plane strain condition, but there is also a common observation that there is no a strong dependence of the sample size on the fracture toughness values. The present study explores this question experimentally, examining three common thermo plastic materials (acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polycarbonate (PC)) manufactured using the fused filament fabrication (FFF) process. Di ff erent specimen sizes were used, none of which met the plane strain criterion specified in the standard. Across several replications and analysis of the experimental data, it was found that there was no statistically signif icant e ff ect based on sample size. It was concluded that, at least within the size range and materials studied, there is no significant di ff erence in output values based on sample size and that the tests were repeatable across di ff erent sample sizes. This suggests that either the samples reached plane strain condition at a smaller size than expected by the standard or that there is not a large di ff erence between plane strain and plane stress conditions for FFF-processed CT samples. This fundamental conclusion was that the ASTM D5045 standard is a valid and useful way to test the linear-elastic fracture properties of FFF-processed thermoplastics. © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023. Keywords: Thermoplastic additive manufacturing; fracture testing; design of experiments; fused filament fabrication 3rd International Workshop on Plasticity, Damage and Fracture of Engineering Materials (IWPDF 2023) Impact of Compact Tension Specimen Size on Fracture Toughness of FFF-Processed Thermoplastics Jose Beltra Mira a , Vanessa Restrepo a , Bhaskar Vajipeyajula a , Albert E. Patterson a, ∗ a TexasA & M University, College Station, 77843, Texas, USA

1. Introduction 1. Introduction

The ASTM D5045 standard [1] is one of the most widely-used and cited methods for estimating the fracture toughness of thermoplastic materials within the linear-elastic domain. This standard is simple to implement and does not depend on J-integrals and similar tools to estimate fracture toughness. While used for the majority of fracture mechanics studies in the literature for additively manufactured (AM) thermoplastic materials [2–12], it is widely known that these materials often fail to meet the stated criteria for true plane strain for the calculation of fracture The ASTM D5045 standard [1] is one of the most widely-used and cited methods for estimating the fracture toughness of thermoplastic materials within the linear-elastic domain. This standard is simple to implement and does not depend on J-integrals and similar tools to estimate fracture toughness. While used for the majority of fracture mechanics studies in the literature for additively manufactured (AM) thermoplastic materials [2–12], it is widely known that these materials often fail to meet the stated criteria for true plane strain for the calculation of fracture

∗ Corresponding author. Tel.: + 01-979-845-4953. E-mail address: aepatterson5@tamu.edu ∗ Corresponding author. Tel.: + 01-979-845-4953. E-mail address: aepatterson5@tamu.edu

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of IWPDF 2023 Chairman 10.1016/j.prostr.2024.06.021 2210-7843 © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023. 2210-7843 © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023.