Naval Surface Warfare Center

About: Naval Surface Warfare Center is a facility organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Radar & Sonar. The organization has 2855 authors who have published 3697 publications receiving 83518 citations. The organization is also known as: NSWC.

Study of composite joint strength with carbon nanotube reinforcement

Abstract: In order to strengthen the interface of a composite scarf joint, this study investigated the benefits of using locally applied carbon nanotubes to reinforce a carbon fiber composite scarf joint. The effect of carbon nanotubes on enhancing the fracture toughness and interface strength was investigated by performing Mode I and Mode II fracture tests with and without carbon nanotubes applied locally at the joint interface. Furthermore, the effects of seawater absorption and different carbon nanotube concentration values on Mode II fracture were investigated. Finally, a partial application of carbon nanotubes only near the crack tip area was considered. During the study, the image correlation technique was used to examine the fracture mechanisms altered by the introduction of carbon nanotubes. The experimental study showed that an optimal amount of carbon nanotubes could increase the fracture toughness of the composite joint interface significantly, especially for Mode II, including a physical change in the fracture mechanism.

Pressure, Temperature Reaction Phase Diagram for Ammonium Dinitramide

Abstract: The pressure, temperature reaction phase diagram for ammonium dinitramide (ADN) was determined using a high-temperature−high-pressure diamond anvil cell with optical polarizing light microscopy, Fourier transform infrared spectroscopy, laser-Raman spectroscopy, and energy dispersive X-ray diffraction. The phase diagram was determined between ambient pressure and 10.0 GPa over the temperature range from −75 °C to decomposition temperatures, or 120 °C. The diagram delineates the melting curve for α-ADN, a reversible phase transition in α-ADN forming a new high-pressure monoclinic polymorph, β-ADN, and also identifies the pressure and temperature conditions at which a solid phase rearrangement occurs to form ammonium nitrate (AN) and N2O. Energy dispersive X-ray diffraction and Raman spectra were obtained for both α- and β-ADN as a function of pressure at room temperature.