Interlaminar Behavior of Multifunctional Graphene Reinforced Composites
Abstract
The performance of a composite material is heavily influenced by the strength and toughness of the interlaminar region, which is the resin rich area between adjacent plies. The interlaminar region generally provides a direct path for crack initiation and propagation since no continuous reinforcement is present and thus dictates the delamination resistance of composites. Delamination specifically can result in catastrophic structural failure especially in materials subjected to cyclic loading such as in rotorcrafts. The interlaminar region is of further concern for multi-material composites that blend plies of different reinforcing materials such as carbon and glass fabrics, where varying stiffness and coefficient of thermal expansion cause high stress concentrations between the plies. Over the past few decades, numerous interlaminar reinforcement approaches have been developed resulting in four principle methods for the enhancement of the interlaminar strength in composite materials, namely; interleaving (addition of thermoplastic polymers in between plies), fiber whiskerization (growth of whiskers or nanowires on the fiber surface), Z-pinning or stitching (addition of through-the-thickness reinforcement) and nanocomposite matrices (addition of a nano-material to the polymer resin). Of these approaches, carbon nanotubes (CNTs) have gained the most attention; however, CNTs are costly, produced at high temperature and under vacuum and are difficult to disperse. Recently, graphene has emerged as a promising alternative to CNTs and significant progress has been made in its production and use as a reinforcement in polymer matrix composites. The manufacture of graphene has been recently made compatible with prepregs and continuous films through the laser induced graphene (LIG) fabrication process. This method uses pulsed laser irradiation from a low-cost CO2 infrared laser to photothermally convert the surface of polymers such as polyimide, polyether ether ketone (PEEK) and poly (paraphenylene terephthalamide) (PPTA) to a three-dimensional network of porous graphene. The compatibility of the process with PEEK enables the graphene to be directly grown on the surface of thermoplastic prepregs or it can be transferred to the surface of thermosetting prepregs using a stick and peel process. The PI has recently shown that this approach can lead to significant interlaminar strengthening while also having the ability to embed strain and damage sensing networks in the material through impedance measurements. The proposed research would seek to correlate the structure of the graphene to the interlaminar reinforcement both through numerical modeling and experimental testing. A fundamental understanding of the mechanism governing the improvements in interlaminar properties of fiber reinforced composites when using the novel LIG will be gained. Additionally, this research will provide fundamental insight into the multifunctional properties afforded to the composite materials due to the piezoresistive nature of the graphene nanomaterial.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 22, 2022
- Source ID
- W911NF2210270
Entities
People
- Henry A Sodano
Organizations
- Army Contracting Command
- United States Army
- University of Michigan