Session: 04-24-05: Materials Processing and Characterization V

Paper Number: 168375

Short Beam Shear Analysis and Characterization of Carbon Fiber Reinforced Polyether Ether Ketone Three-Phase Composite With Carbonized PAN Fibers
 

Abstract

Short beam shear (SBS) analysis is a critical method for evaluating the interlaminar shear strength (ILSS) of composite materials. This study focuses on the shear behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites, where the reinforcing phase consists of carbonized polyacrylonitrile (PAN) fibers. CF/PEEK composites are increasingly used in high-performance applications such as aerospace, automotive, and sporting goods due to their exceptional mechanical properties, including high strength-to-weight ratio, chemical resistance, and thermal stability. Polyether ether ketone (PEEK) is a high-performance thermoplastic polymer known for its excellent thermal stability, chemical resistance, and mechanical strength. When reinforced with carbon fibers, the resulting composite benefits from the high stiffness, strength, and thermal conductivity of the fibers. Carbonized PAN fibers are widely used as reinforcements due to their high tensile strength, modulus, and resistance to creep and fatigue. The strong interfacial bonding between carbonized PAN fibers and the PEEK matrix is crucial for enhancing the overall mechanical performance, particularly under shear loading conditions. 

The short beam shear test was conducted in accordance with ASTM D2344 standards, which specify the procedure for determining the ILSS of composite materials. Test specimens were prepared through a hot press molding technique to ensure consistent fiber distribution and optimal fiber-matrix bonding. The specimens were cut to precise dimensions and tested using a three-point bending setup. During the test, load was applied at a constant rate until failure, and the maximum load and corresponding displacement were recorded.

The results demonstrated that CF/PEEK composites reinforced with carbonized PAN fibers exhibited high ILSS values, indicating strong interfacial bonding and effective stress transfer between the fibers and the matrix. The high shear strength was attributed to the inherent properties of carbonized PAN fibers and the strong adhesion with the PEEK matrix. Fractographic analysis using scanning electron microscopy (SEM) revealed cohesive failure patterns along the fiber-matrix interface, suggesting that failure occurred through matrix shear rather than fiber pull-out. This indicates efficient load transfer and minimal fiber debonding, which are essential for high shear performance.  Furthermore, the microstructural analysis showed that fiber orientation and matrix uniformity played significant roles in shear strength. The alignment of carbonized PAN fibers along the loading direction enhanced the composite's resistance to shear-induced delamination. The tough nature of the PEEK matrix allowed the composite to absorb significant energy before failure, contributing to improved damage tolerance and fracture resistance. 

The findings of this study highlight the potential of CF/PEEK composites reinforced with carbonized PAN fibers for structural applications requiring high shear strength and durability. The strong interfacial bonding and resistance to micro-cracking make these composites suitable for aerospace and automotive components, where high-performance materials are essential. Future work could explore the effects of varying fiber content, fiber orientation, and matrix modification to further enhance the shear properties and overall mechanical performance of CF/PEEK composites under complex loading conditions.

keywords: short beam shear, hot press, fiber bonding, fractography.

Presenting Author: Nitin More North Carolina Agricultural and Technical State University

Presenting Author Biography: Myself Nitin More PHD student at North Carolina Agricultural & Technical State University in Nanoengineering Department. My research interest is in Thermoplastic composites, Additive Manufacturing and Nanofibers.

Authors:

Nitin More North Carolina Agricultural and Technical State University
Ram Mohan North Carolina Agricultural & Technical State University