Research
Multifunctional Materials

Composites are materials composed of at least two distinct phases (for example carbon fibers in a polymer matrix) in a defined geometric relationship, which are constructed in such a manner that the overall properties of the new composite material greatly exceeds the properties of the homogeneous constituent phases. Research activities include processing, characterization, micromechanics, fracture, fatigue and dynamic behavior, damage mechanics, nondestructive evaluation, and life prediction.

Experimental, analytical, and computational methods are pursued to drive fundamental understanding of the behavior of these multiphase, multifunctional systems as well as to develop methodologies for tailored and predictive design of composite materials with superior properties.

The program is supported by well equipped laboratories which include chemical hoods, presses, autoclaves, and state of the art RTM equipment for synthesis and fabrication of composites; test systems for nano- and micro-mechanical as well as large scale studies, with chambers providing test environments from cryogenic to over 1500° C temperatures; and dynamic, experimental stress analysis, and nondestructive test facilities. Laboratory facilities are complemented by extensive computer resources.

Research Areas

Processing

Northwestern University has capabilities, experience, and ongoing activities in processing of polymer matrix composites, including nanocomposites and hybrid nano/microcomposites. Processing methods used include autoclave molding, resin transfer molding (RTM), and vacuum assisted resin transfer molding (VARTM). Special techniques have been developed for fabrication of transparent composites, thick composites, and nanocomposites. A Center for Intelligent Processing of Composites (IPC) has been established at Northwestern University.

Polymer Matrix Composites

Research activities in the general area of polymer matrix composites include processing, characterization, micromechanics, fracture, fatigue and impact behavior, constitutive modeling, dynamic characterization, damage mechanics, nondestructive evaluation, and life prediction. Examples of some applications are shown below.

Kink band failure pattern under longitudinal compression.

Northwestern University has capabilities, experience, and ongoing activities in processing of polymer matrix composites, including nanocomposites. Processing methods used include autoclave molding, resin transfer molding (RTM), and vacuum assisted resin transfer molding (VARTM). Special techniques have been developed for fabrication of transparent composites, thick composites, and nanocomposites. A Center for Intelligent Processing of Composites has been established at Northwestern University.

Hybrid Nano/Micro Composites

Conventional structural composites, usually consisting of a polymeric matrix reinforced with continuous glass or carbon fibers, have many desirable properties; however, they exhibit some weak points associated with the polymeric matrix. Matrix dominated mechanical properties, such as in-plane and interlaminar shear properties and compressive strength, are much lower than fiber dominated properties. These properties can be enhanced by incorporating nanoparticles, nanoplateles or nanotubes in the matrix. Special processing methods have been developed and results are encouraging.

Processing of hybrid nano/micro composite with graphite nanoplatelets.

Faculty