Programs such as Airborne Laser and Space-Based Laser are in need of highly mass efficient structural materials to achieve system performance targets. This naturally leads to graphite fiber reinforced polymers for many system components. For some applications, such as cryogen storage vessels, these materials are subject to micro cracking under little or no structural loading. New materials with equivalent or superior specific properties that are resistant to micro cracking are needed for these applications. The recent focus on material particles with nanometer scale dimensions offers the opportunity to employ multiscale reinforcement in polymers by reinforcing the resin at the nano-scale within a conventional "micro-scale" composite. Relatively little attention has been devoted to understanding and optimizing the structural benefits of these materials. There is demand, however, for exploiting the possibilities for improved structural performance through the design of multiscale, three-constituent composites. Advanced multiscale material modeling is perhaps the most effective way to explore the potential benefit of three phase material systems and gain understanding that will lead to new materials designed for certain performance objectives. This project will apply multiscale modeling techniques to devise new materials and structure design strategies that result in composite structures resistant to damage in deep thermal cycle environments. Anticipated Benefits/Commercial Applications: The results of the work proposed herein have broad commercial potential. The storage of liquids and liquid cryogens in lightweight containers is an important design issue in all types of air and space vehicles today. Lightweight composite storage tanks are of particular interest in both the Airborne Laser (ABL) and Space Based Laser (SBL) programs. Particular emphasis in modeling and analysis capabilities is placed on the SBL program due to the fact that actual testing scenarios that simulate space conditions are nearly impossible. For this reason, the ability to model and predict the responses of these composite storage tanks under in-service conditions has a large commercial potential. As composite materials are more widely used for increasingly severe mechanical and thermal loading situations there is an inherent need to understand their behavior under application and to tailor their properties to meet the design needs. The ability to model not only constituent variations but also nano reinforcement modifications will be key to the successful application of three-phase (multiscale) composite material systems. The ability to provide material design guides and criteria along with structural analysis capabilities to both government and private industry is vital to the commercial success of the proposed research. We feel that strong commercial potential exists in both the sale of analysis and design software for composites that include nano-scale reinforcement, and for technical consulting work related to deep thermal cycle applications and associated material modification.
Keywords: composite materials, finite element, micromechanics, multiscale analysis, nano composite
