Investigations on Dynamic Characterization of Nanophased Fiber Reinforced Polymeric Composites Subjected to Naval Environmental Conditions

 Grant Number:  W911NF-12-R-0053 funded by Department of Defense (DoD)

 PI: Mahesh Hosur, Professor of Materials Science and Engineering,

 Co-PI: Shaik Zainuddin, Assistant Professor of Materials Science and Engineering

Fiber Reinforced Polymer Composites (FRPC) are increasingly used in DoD, particularly in the US naval and military applications due to considerable weight and life-cycle cost savings, good corrosion resistance, and improved fatigue performance over metallic counterparts. These structures are expected to have a long service life while operating in marine environment that consists of saline and cold (subzero: dry, wet) water conditions which degrade their performance due to inherent viscoelastic nature of FRPs.  Hence, durability of FRPC for DoD facilities based on the deformation and degradation mechanisms needs to be established, especially under these conditions. These can be developed with the aid of accelerated aging experiments. With the recent developments in the nanocomposites for structural applications, several types of nanoparticles have been established to bring significant improvement in the thermal and mechanical properties of the polymers used for FRP applications. Of these, carbon nanotubes and nanoclay are the most widely used because of excellent stress transfer, strong interfacial interactions and good barrier resistance properties.

Through this grant, we are studying the degradation and deformation behavior of both control and nanophased carbon/epoxy composites under marine environment conditions specifically under dynamic loading like high strain rates, high velocity impact and fatigue loading. Laminates are fabricated with different weight percentage of nanoclay and carbon nanotubes and then subjected to saline water, cold (subzero: dry, wet) and room temperature conditioning for different time lengths (30, 60, 120 and 180 days). Degradation in specimens caused due to the exposed conditions is being examined through micrographic and nondestructive evaluation (NDE) studies. Accelerated testing is being carried out to study the deformation behavior of FRPC specimens under both static and cyclic flexural and tensile loading. Durability prediction of control and nanophased FRPC is being performed using time-temperature superposition (TTS) principle. High strain rate and high velocity impact tests are being carried out. In addition, damage propagation and failure behavior of fractured specimens are analyzed using noncontact plasma thermography and ultrasonic nondestructive evaluation, and scanning electron microscope (SEM).

Several graduate and undergraduate students are involved with research activities. Additional support for these activities is provided through NSF-EPSCoR, NASA-EPSCoR and UNCF-SP/NASA funded programs. 

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