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Nanostructured Ceramics
This work was funded by the Office of Naval Research (ONR)
and was performed in collaboration with Advanced Ceramics
Manufacturing, Tucson, AZ. The research goal of this effort
was to develop strategies to reduce the size of the grains
(crystals) in silicon nitride materials in order to improve
properties such as toughness and hardness. (Silicon nitrides
are being developed for use in high-temperature structural
applications but their lack of toughness has proved to be an
impediment.) Strategies such as the addition of nano-sized
secondary phases such as carbon nanotubes were developed and
shown to be effective in refining the microstructure and
improving the toughness of these ceramics. Two graduate
students obtained a Masters degree based on this work. Two
ME undergraduates spent a summer each assisting in this
research project.
Delamination in Laminated Composite
Materials
This project, funded by ONR and Materials Sciences
Corporation, PA, explored analytical methods for predicting
fractures at interfaces in laminated composite materials. A
method was developed, using principles of solid mechanics,
to calculate parameters that can predict when fracture can
occur at the interfaces of layered materials. Three graduate
student Masters theses contributed to this work.
Mechanics of Shape Memory Alloy
Composites
This project, funded by ONR, explored the mechanical
behavior of a special class of metal alloys called shape
memory alloys. Shape memory alloys have some unique
properties wherein their shape can be changed quite
significantly and then restored by a simple heating action.
The concept explored in this research was to create
structural composite material parts with embedded shape
memory alloy wires which would allow the parts to be
reconfigurable. A nonlinear, micromechanics-based analytical
model was developed to predict the behavior of shape memory
alloy composites. Two graduate students wrote their Masters
theses based on some of this work.
Constitutive Model for Carbon
Carbon Composite Materials
A constitutive model has been constructed for a
Carbon/Carbon composite material that is used in the leading
edges of the space shuttle. This model has been integrated
as a user material subroutine in the finite element code
ABAQUS.
Fabrication and Characterization of Biomimetic Ceramics
Great complexity in structure is seen in nature’s biological
composites. These natural biocomposites achieve a damage
tolerance 10,000 times higher than their individual
constituents via a multi-length scale (third order), crossed
lamellar architecture. In this research project, we plan to
work with Advanced Ceramics Manufacturing (AZ) to improve
the damage tolerance of ceramic systems by mimicking the
crossed lamellar microstructure found in sea shells such as
Strombus Gigas. It is believed that processes similar to
those used in Fibrous Monolith fabrication could be adapted
to engineer third order biomimetic micro-structures. Ultra
tough ceramics would enable impact resistant turbine blades,
multi-hit capable armor, high performance – high reliability
rocket motors, chip resistant cutting tools, and more
reliable hard tissue medical implants. This project aims to
develop an advanced, biomimetic, damage-tolerant, ceramic
composite material for high performance structural and
thermal protection applications. These ceramics will have
high toughness, the ability to resist corrosive
environments, and the possibility of use in thermal
protection systems. This work is funded through an SBIR
Phase I grant from NSF.
Lightweight Structures in Roadside
Blast Protection
Enhanced energy dissipation in a blast protection system
is considered in this work. Our approach is to consider
materials and structures historically used in lightweight
blast-protection systems like an array honeycomb cells and
improve the energy dissipation ability. This work is funded
by ONR through a Phase I SBIR grant to Ablaze Corp. |
