In the last few years nanocomposites have emerged as the new class of materials which are likely to revolutionize the future structural components. These nanocomposites which consist of polymers with nanometer-sized particles have exhibited considerable improvements in chemical, thermal, mechanical properties in addition to improved barrier properties. It is all the more fascinating that these improvements occur at a very low loading percentage of nanoparticles. Researchers at Tuskegee University's Center for Advanced Materials have successfully incorporated a variety of nanoparticles with thermosetting and thermoplastic polymers and extended the concept to manufacture structural nanocomposites. Through this approach they have achieved enhancements in strength and stiffness over their neat polymeric composites. In this major research instrumentation proposal, we are seeking to acquire a state-of-the-art ultrasonic C-scan system to assist and enhance the quality of various aspects of the ongoing research projects funded by NSF, ARO, ONR and EPSCoR. A large number of African-American students, both at undergraduate and graduate level with many at Ph.D. level, will be trained in nondestructive characterization of new class of materials, structural nanocomposites. It is only expected that many younger minority students will be encouraged to take up graduate studies when exposed to state-of-the-art facilities like the proposed ultrasonic C-scan system at early stages of their science and engineering education.
Structural nanocomposites have potential to become materials of the future as they have potential to have higher strength and stiffness as compared to current generation fiber reinforced composite materials. Most of the research carried out to date on nanocomposites is focused on the improvement of properties of nanophased matrix systems. In the ongoing research work at Tuskegee University Center for Advanced Materials (T-CAM), attempts are being made to model, synthesize, manufacture and characterize nanophased structural composites. Any such development requires techniques to evaluate elastic properties, defects and damages during manufacture and under different loading conditions using nondestructive evaluation (NDE) techniques. Through this proposal, we are planning to acquire a state-of-the-art ultrasonic nondestructive evaluation (NDE) system. Using this facility, it is planned to understand the cure kinetics using velocity and attenuation measurements through ultrasonic means, optimize the process of fabrication of structural nanocomposites using VARIM process, quantify fabrication defects, evaluate the elastic properties of new class of nanophased composites through nondestructive means, determine the degradation of nanophased composites when subjected to environmental conditioning, evaluate the progressive growth of damages during fatigue loading, estimate the damage due to low-velocity and ballistic impact loading and evaluate the defects induced during the fabrication of integral skin-stringer assembly by VARIM process and isogrid cylinders by filament winding. We propose to characterize, by means of ultrasonic NDE, different class of nanocomposites that are made using various types of nanoparticles, resin systems and fibers. Finally, through this program, a large number of African-American students, both at undergraduate and graduate level with many at Ph.D level, will be trained in nondestructive characterization of new class of materials: structural nanocomposites.
