Coordinator: Dr. Kunigal Shivakumar, Department of Mechanical Engineering

Participating faculty:

• Dr. Julius Harp, Department of Chemistry
• Dr. Messiha Saad, Department of Mechanical Engineering
• Dr. Zhijian Xie, Department of Electrical Engineering

Aerospace material challenges

A variety of material challenges continues to limit aerospace vehicles’ performance and energy efficiency: compression and compression after-impact strength, poor interlaminar toughness, conductivity (electrical and thermal), high moisture absorption, susceptibility to fire, and a synergetic effect of these combinations. This task aims to understand the limitations of composite materials and to improve their performance through nanotechnology, precise characterization, and development of accurate predictive models.

1.1  Polymer nano composites

PI: Dr. Shivakumar

Nanocomposites research in the center is based on three concepts: matrix modification through the use of nanofillers to improve multifunctional properties as well as compression strength; fiber surface modification to improve interfacial strength of the composite materials; and polymer nanofiber interlayer reinforcement to enhance fracture toughness, structural damping, and relieve edge stresses to produce high TRL composites. 

1.2  Interlayer reinforcement

PI: Dr. Shivakumar

This is the major research topic in the center because of its potential for multifunctionalizing composite laminates and a potential for high TRL research. The research elements include fracture toughness and resistance, fracture and fatigue onset, mixed-mode fracture toughness, mitigation of edge stresses, impact damage assessment, and electrospinning. The original research focus was on electrospun thermoplastic polymer nanofiber interleaving; it now has been expanded to include polymer film interleaving. 

1.3  Total fatigue life models

PI: Dr. Shivakumar

This is a major long-term research objective of the center. The Total Life Model method requires development of delamination growth model consisting of delamination onset, linear growth rate, and fast growth or fracture. The stress state controls the characteristics of the model. Therefore, a damage-tolerant design of structures requires total life model and fracture criterion for final failure. Therefore, the research requires a detailed fatigue and fracture experimental study of delaminated composite laminate and development of models.

1.4  Thermal and electrical characterization

PI: Dr. Shivakumar

Composite materials have exceptional advantage over traditional materials for their light weight, high strength and stiffness, high resistance to corrosion, and improved fatigue life, resulting in low maintenance. The primary disadvantage is that composites are susceptible to lightning strike due to low thermal and electrical conductivity and electromagnetic property. A number of explorations are being made to improve these properties; one such effort is being made through functionalizing polymer composites through graphene platelets.

1.5  Application of Eco-Core for turbofan engine-noise reduction

PI: Dr. Shivakumar

Noise management in engines is a major thrust under the NASA’s ARMD subsonic aircraft program. NC A&T has developed Eco-Core of low density and structured configuration and appears to have an application in noise reduction in aircraft engine nacelle area. If the technology is successful, the outcome of technology will be valuable to engine manufacturers and architects for building acoustics.

1.6  Development and evaluation of monomers, PI: Dr. Harp

PI: Dr. Harp

Molecular design of physical/photo/thermo/chemical inducing macromolecular platforms to be covalently attached to molecules (i.e., a molecular modifier) with pre-determined properties by strategic linkage to yield constructs (i.e., materials and structures) with enhanced desired properties and controllable structural framework. This will be useful in applications such as photo imaging, photovoltaic and galvanic cells, vehicle/structural health safety management, biomimetics, robotics, and medicinals.

1.7  Passive RFID and sensor technology

PI: Dr. Xie

RFID with ultra-small form factor will enable smart material, which can report material health at run time. Miniature RFID also can be used to monitor critical components to make sure the system is constructed from trusted resources.