The Role of Nanoporous Networks in the Out-of-Autoclave Manufacturing of Aerospace-Grade Carbon Fiber Reinforced Polymer Composites
Topic(s) : Manufacturing
Co-authors :
Alisa WEBB (UNITED STATES), Jingyao DAI (UNITED STATES), Brian L. WARDLEAbstract :
Autoclaves are traditionally used to process aerospace-grade fiber-based composites through convective heating and compressive pressure, resulting in low void volume fraction composites. However, major drawbacks of this industry-standard technique include intensive time and energy costs, geometric constraints on manufactured parts, and lower accessibility to smaller companies.
To overcome these obstacles, we developed a process that uses nanoporous networks (NPNs) to produce aerospace-grade carbon fiber reinforced polymer composites without the use of an autoclave. NPNs are generally conformable, porous materials with pore sizes ranging from nanometers to sub-micrometers. The nanoscaled microstructure of the NPNs result in high capillary pressure that replaces the autoclave pressure to manufacture void free interlaminar regions. During the manufacturing process, the high capillary pressure induced by the NPNs will promote resin infusion into the interlaminar regions which are generally prone to void formation. An investigation into the microstructure and pore size of various NPNs is completed using capillary flow porometry (CFP), scanning electron microscopy (SEM), and X-ray microcomputed tomography (μCT) to provide insight into the effect of capillary pressure on void content.
Utilizing a model based on Darcy's Law, the permeability and achievable capillary pressure range of these NPNs were used to predict the resin flow front within the NPNs throughout the cure cycle. To validate the model, an in-situ μCT experiment is developed to directly observe real time resin flow through NPNs from surrounding pre-impregnated laminas as a function of temperature. Through the use of 2D projections, unidirectional composite systems, along with laminates with more complex morphologies such as woven laminates, can be investigated throughout a varying temperature profile, demonstrating the conformability of NPNs during resin flow, along with the flow front. As resin viscosity and void content change throughout the cure cycle, it’s necessary to obtain spatial temporal information that demonstrates this novel out-of-autoclave manufacturing process and further our understanding of the prepreg-NPN interactions within a laminate. A 3D volumetric scan in-situ experiment was developed to investigate this composite behavior with varying temperature profiles.
Via measuring permeability and capillary pressure results, a guideline Ashby chart is created to help guide manufacturers in appropriate NPN selections for their carbon fiber reinforced polymer matrix systems. We anticipate that this work will help advance the understanding of out-of-autoclave manufacturing of carbon fiber composites and provide a potential solution to the energy, time, manufacturing, and accessibility costs associated with autoclaves.
To overcome these obstacles, we developed a process that uses nanoporous networks (NPNs) to produce aerospace-grade carbon fiber reinforced polymer composites without the use of an autoclave. NPNs are generally conformable, porous materials with pore sizes ranging from nanometers to sub-micrometers. The nanoscaled microstructure of the NPNs result in high capillary pressure that replaces the autoclave pressure to manufacture void free interlaminar regions. During the manufacturing process, the high capillary pressure induced by the NPNs will promote resin infusion into the interlaminar regions which are generally prone to void formation. An investigation into the microstructure and pore size of various NPNs is completed using capillary flow porometry (CFP), scanning electron microscopy (SEM), and X-ray microcomputed tomography (μCT) to provide insight into the effect of capillary pressure on void content.
Utilizing a model based on Darcy's Law, the permeability and achievable capillary pressure range of these NPNs were used to predict the resin flow front within the NPNs throughout the cure cycle. To validate the model, an in-situ μCT experiment is developed to directly observe real time resin flow through NPNs from surrounding pre-impregnated laminas as a function of temperature. Through the use of 2D projections, unidirectional composite systems, along with laminates with more complex morphologies such as woven laminates, can be investigated throughout a varying temperature profile, demonstrating the conformability of NPNs during resin flow, along with the flow front. As resin viscosity and void content change throughout the cure cycle, it’s necessary to obtain spatial temporal information that demonstrates this novel out-of-autoclave manufacturing process and further our understanding of the prepreg-NPN interactions within a laminate. A 3D volumetric scan in-situ experiment was developed to investigate this composite behavior with varying temperature profiles.
Via measuring permeability and capillary pressure results, a guideline Ashby chart is created to help guide manufacturers in appropriate NPN selections for their carbon fiber reinforced polymer matrix systems. We anticipate that this work will help advance the understanding of out-of-autoclave manufacturing of carbon fiber composites and provide a potential solution to the energy, time, manufacturing, and accessibility costs associated with autoclaves.