Entity

Time filter

Source Type

Seattle, WA, United States

Drakonakis V.M.,Polymeric Composites Laboratory | Drakonakis V.M.,University of Nevada, Reno | Aureli M.,University of Nevada, Reno | Doumanidis C.C.,Khalifa University | Seferis J.C.,Polymeric Composites Laboratory
Composites Part B: Engineering | Year: 2014

Mechanical and weight properties of polymer nanocomposites (PNCs) are measured and modeled at the interlaminar region, predicting the density and elastic modulus of individual carbon nanotubes (CNTs). A simple model of the CNTs density and elastic modulus within the PNC, accounting for fundamental material properties, geometry, and interactions, is developed, capable of predicting CNT contributions in the PNCs. Furthermore, the model is validated with experimental results that demonstrate enhancement of the elastic modulus, while reducing density in the presence of aligned CNTs. By establishing an inverse relation of density and elastic modulus (negative correlation), it is demonstrated the potential of increasing mechanical properties while reducing weight. Therefore, by introducing controlled nanoporosity through suitable CNT distributions within the interlayer of multi-lamina structures, it is possible to simultaneously control effective weight reduction and enhanced modulus, toward bio-inspired carbon fiber reinforced polymer composites. © 2014 Elsevier B.V. All rights reserved. Source


Kamp C.J.,Massachusetts Institute of Technology | Seferis J.,Polymeric Composites Laboratory | Arnold M.,Polymeric Composites Laboratory | Drakonakis V.,University of Nevada, Reno
SAE International Journal of Materials and Manufacturing | Year: 2014

Nanobridization is a nano-inspired process by which scalable material structures can be designed and manufactured by combining the concept of 'Nano Free Volume' with specific material molecules defining a systemic density (nano-density). This approach explores nanotechnology from a porosity perspective rather than nanoparticles thus minimizing health concerns with nanotechnology, while providing nanoporosity throughout the entirety of the composite system. Nanobridization may be viewed as a density system transformation of material heterogeneity utilizing a unified class of materials such as Polynanomers and in developing next generation structures such as Featherweight Carbon Fiber Reinforced Polymers (CFRP). Polynanomers are further defined by the incorporation of hollow carbon fibers, electrospun nano-fibers, nano-pores and carbon nanotubes (CNT) into this newly established type of matrix. Nanobridization involves fractal structural design and constitutes a scalable structure from the nano- to the macro- scale and vice versa, resulting in a spatial density with significant overall weight reduction. Featherweight composites are a characteristic example product of nanobridization process, as they include novel bio-inspired fractal structures which are combined with unprecedented mechanical and transport properties. Porosity is designed both at the macro- (honeycomb/foam type) and micro- (hollow carbon fiber foamed matrix and interphase) scales and can find immediate applications such as tooling and nonstructural or failure critical applications. Featherweight composite manufacturing introduces a new production process which includes novel steps, such as electrospinning of carbon fibers and aligned CNT incorporation into the novel polynanomeric matrix system, and an innovative, integrated, roll-to-roll (R2R) process sequence. The main objective of this work is to discuss the manufacturing scalability of polynanomeric composites through nanobridization and to highlight potential relevant uses for this technology in the automotive industry. This type of material establishes a unique framework for creating the next-generation of composites technology that will be 25 to 40% lighter, while maintaining structural load-bearing characteristics such as stiffness and strength. Various polynanomers have been investigated in the Polymeric Composites Laboratory and will be discussed in this article. © 2014 SAE International. Source


Drakonakis V.M.,Polymeric Composites Laboratory | Drakonakis V.M.,University of Texas at Arlington | Seferis J.C.,Polymeric Composites Laboratory | Doumanidis C.C.,University of Cyprus
Advances in Materials Science and Engineering | Year: 2013

Autoclaving is a process that ensures the highest quality of carbon fiber reinforced polymer (CFRP) composite structures used in aviation. During the autoclave process, consolidation of prepreg laminas through simultaneous elevated pressure and temperature results in a uniform high-end material system. This work focuses on analyzing in a fundamental way the applications of pressure and temperature separately during prepreg consolidation. A controlled pressure vessel (press-clave) has been designed that applies pressure during the curing process while the temperature is being applied locally by heat blankets. This vessel gives the ability to design manufacturing processes with different pressures while applying temperature at desired regions of the composite. The pressure role on the curing extent and its effect on the interlayer region are also tested in order to evaluate the consolidation of prepregs to a completely uniform material. Such studies may also be used to provide insight into the morphology of interlayer reinforcement concepts, which are widely used in the featherweight composites. Specimens manufactured by press-clave, which separates pressure from heat, are analytically tested and compared to autoclaved specimens in order to demonstrate the suitability of the press-clave to manufacture high-quality composites with excessively reduced cost. © 2013 Vasileios M. Drakonakis et al. Source


Drakonaki V.M.,University of Cyprus | Drakonaki V.M.,Polymeric Composites Laboratory | Drakonaki V.M.,Massachusetts Institute of Technology | Sfakianakis A.,Polymeric Composites Laboratory | And 3 more authors.
25th Technical Conference of the American Society for Composites and 14th US-Japan Conference on Composite Materials 2010 | Year: 2010

Carbon fiber reinforced composites are used more and more in high tech applications. The quest for even lighter structures without sacrificing mechanical properties is a key factor in the next generation of composite materials, feather weight composites. Feather weight carbon fiber reinforced composites introduce nano-free volume both within the matrix and the fibers in order to lighten the composite, without giving up mechanical strength. The polymer composite layer layout and bonding has become an important process used in high tech applications. Nevertheless, from both an analysis as well as a manufacturing point of view, the lamination process is expected to yield an apparently homogeneous structure with a uniform nano-free volume distribution through the thickness of the material. This work presents an effort to develop a controlled nano-free volume within the matrix system of a composite. Carbon nanotubes, which can be considered as hollow multilayered tubes, are introduced within the matrix creating nanoporosity. Therefore, an analysis of the matrix system and the carbon nanotube density as well as their strong relation to the carbon nanotube number of walls and external radius is presented. Finally, the effect of nanotubes on the composite modulus and strength is analytically investigated. Source


Barrois L.,Polymeric Composites Laboratory | Drakonakis V.M.,Polymeric Composites Laboratory | Drakonakis V.M.,Massachusetts Institute of Technology | Drakonakis V.M.,University of Cyprus | And 7 more authors.
International SAMPE Symposium and Exhibition (Proceedings) | Year: 2010

Polymeric composites have gone through a level of maturity beyond the laboratory stage with the development of the mainly composite aircraft, Boeing 787 and Airbus 350. These composite materials, utilized in aerospace structures, both thermosets and thermoplastics, are exposed to severe environmental conditions during their life span. More specifically, they are exposed to moist environments while undergoing thermal shock during landing and takeoff. This work presents a systemic methodology to investigate thermoset and thermoplastic carbon fiber reinforced polymers (CFRP) through thermal analysis that have been exposed to sudden thermal cycles. Additionally, this effort compliments our ongoing investigation of a Boeing DC10 (formerly McDonnell Douglas) vertical stabilizer owned by Seferis enterprises and used in training the next generation scientist engineers and managers of the technology. The vertical stabilizer was made out of CFRP of 1980s vintage and it has been in use for more than 50.000 flight hours. Collectively then, this work provides a unique opportunity in examining CFRP behavior from laboratory to airplane usage and beyond in establishing design parameters for the next generation of polymeric composite material and processes. Source

Discover hidden collaborations