Session: 01-06-02: Impact, Fatigue, Damage and Fracture of Composite Structures 2

Paper Number: 151966

151966 - High-Temperature Mechanical and Fracture Behavior of Additively Manufactured Carbon Fiber-Reinforced Composites 

Carbon fiber-reinforced polyetheretherketone (CF-PEEK) composites, produced through additive manufacturing (AM) techniques such as Material Extrusion (ME)-based 3D printing, show promise for aerospace applications requiring high-temperature resistance, such as engine components. The layered architecture and defect formation occurring at various length scales during the 3D printing process often make CF-PEEK composites prone to interlaminar shear failure, a mode that could be particularly critical in high-temperature environments. This study systematically investigates the interlaminar shear strength (ILSS) of CF-PEEK composites, fabricated via the ME technique, at elevated temperatures up to 125°C. The ILSS was measured using short beam shear (SBS) tests. Digital image correlation (DIC) was employed during the tests to capture in-situ full-field strain maps, facilitating the observation of distinct interlaminar failure mechanisms. Additionally, fractographic analyses were conducted to confirm the observed trends. The experimental findings highlight three key points: (1) The infill layup significantly influences the failure mode: the  and  layups consistently resulted in interlaminar shear failure at room temperature and flexural or interlaminar shear failure at elevated temperatures depending on the layer thickness, whereas the  layup consistently led to flexural failure across all examined temperatures due to enhanced interlaminar shear strength in this layup. (2) The layer thickness used in 3D printing significantly affects the ILSS, with thinner layers resulting in improved interlaminar shear strength for all examined layups and test temperatures, attributed to the reduced defect size with thinner layers. (3) The relationship between temperature and ILSS revealed a complex pattern for different layups and printing layer thicknesses. The ILSS of CF-PEEK composites tended to increase with test temperatures for the  and  layups. Elevated temperatures could result in a failure mode transition from interlaminar shear failure to flexural failure for thinner layers due to significantly increased ILSS. For the  layup, elevated temperatures led to a slightly lower failure strength. These findings suggest that interlaminar shear failure is not a major failure mode in CF-PEEK composites fabricated via the ME technique at elevated temperatures. These conclusions are based on the specific process parameters utilized and can be generalized with the examination of other process parameters.

Presenting Author: Denizhan Yavas Rice University

Presenting Author Biography: Dr. Yavas joined serves as an Assistant Teaching Professor in the Department of Mechanical Engineering at Rice University. He s specializes in experimental and computational solid and fracture mechanics. His focus areas include deformation and failure mechanisms in advanced composite and additively manufactured materials, development of architected and tunable materials, mechanics of thin films and multilayered materials, and interfacial fracture and ice adhesion.