Fracture analysis of rubber toughened additively manufactured thermosets

Megan Shepherd, Kamran Makarian, Giuseppe Palmese, Nicholas Brunstad, Leslie Lamberson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This study explores the role of rubber toughening on the dynamic fracture behavior of additively manufactured (AM) high-performance thermosetting polymers formed through digital light processing (DLP). Using DLP to create these polymers allows for rapid, agile manufacturing of prototypes meeting the lightweight and building speed requirements of relevance to military mission applications. This method also provides flexibility in part complexity while maintaining relatively high isotropy compared to traditional AM techniques. Previous work has demonstrated a dependence of these DLP specimens on print layer orientation and loading rate, prompting further investigation into other manufacturing parameters to improve toughness [1]. This study examines the role of rubber toughening on the quasi-static and dynamic fracture behavior of bis-GMA thermosets. Current literature largely reports on quasi-static behavior of DLP specimens, although dynamic conditions are more applicable to many realistic loading scenarios and extreme environments often seen in defense applications. Dynamic experiments leverage a unique long bar striker device that impacts a specimen opposite a pre-crack, sending a stress-wave driven load to initiate a dynamic Mode-I (opening) fracture event. Full-field displacement data ahead of the propagating crack is obtained using ultra high-speed imaging combined with 2D digital image correlation (DIC). An elastodynamic solution following the principles of dynamic fracture mechanics extracts the stress intensity factor (SIF) using a least squares fit at crack initiation and a Newton-Raphson scheme for crack propagation. The rubber toughened thermosets in this study exhibited a rate dependence in fracture toughness with the quasi-static SIF being 1.20 MPa√m and the dynamic SIF being 0.41 MPa√m.

Original languageEnglish (US)
Title of host publication36th Technical Conference of the American Society for Composites 2021
Subtitle of host publicationComposites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
EditorsOzden Ochoa
PublisherDEStech Publications
Pages871-881
Number of pages11
ISBN (Electronic)9781713837596
StatePublished - 2021
Externally publishedYes
Event36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021 - College Station, Virtual, United States
Duration: Sep 20 2021Sep 22 2021

Publication series

Name36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
Volume2

Conference

Conference36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
Country/TerritoryUnited States
CityCollege Station, Virtual
Period9/20/219/22/21

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites

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